Merge branch 'main' into enum

.pre-commit-config.yaml

@@ -35,7 +35,8 @@ repos:
     rev: 6.0.0
     hooks:
       - id: flake8
-        additional_dependencies: [flake8-2020, flake8-implicit-str-concat]
+        additional_dependencies:
+          [flake8-2020, flake8-errmsg, flake8-implicit-str-concat]
 
   - repo: https://github.com/pre-commit/pygrep-hooks
     rev: v1.9.0

CHANGES.rst

@@ -5,6 +5,30 @@ Changelog (Pillow)
 9.4.0 (unreleased)
 ------------------
 
+- Improve exception traceback readability #6836
+  [hugovk, radarhere]
+
+- Do not attempt to read IFD1 if absent #6840
+  [radarhere]
+
+- Fixed writing int as ASCII tag #6800
+  [radarhere]
+
+- If available, use wl-paste or xclip for grabclipboard() on Linux #6783
+  [radarhere]
+
+- Added signed option when saving JPEG2000 images #6709
+  [radarhere]
+
+- Patch OpenJPEG to include ARM64 fix #6718
+  [radarhere]
+
+- Added support for I;16 modes in putdata() #6825
+  [radarhere]
+
+- Added conversion from RGBa to RGB #6708
+  [radarhere]
+
 - Added DDS support for uncompressed L and LA images #6820
   [radarhere, REDxEYE]
 

Tests/test_file_jpeg2k.py

@@ -252,6 +252,20 @@ def test_mct():
             assert_image_similar(im, jp2, 1.0e-3)
 
 
+def test_sgnd(tmp_path):
+    outfile = str(tmp_path / "temp.jp2")
+
+    im = Image.new("L", (1, 1))
+    im.save(outfile)
+    with Image.open(outfile) as reloaded:
+        assert reloaded.getpixel((0, 0)) == 0
+
+    im = Image.new("L", (1, 1))
+    im.save(outfile, signed=True)
+    with Image.open(outfile) as reloaded_signed:
+        assert reloaded_signed.getpixel((0, 0)) == 128
+
+
 def test_rgba():
     # Arrange
     with Image.open("Tests/images/rgb_trns_ycbc.j2k") as j2k:

Tests/test_file_tiff_metadata.py

@@ -185,20 +185,21 @@ def test_iptc(tmp_path):
         im.save(out)
 
 
-def test_writing_bytes_to_ascii(tmp_path):
-    im = hopper()
+@pytest.mark.parametrize("value, expected", ((b"test", "test"), (1, "1")))
+def test_writing_other_types_to_ascii(value, expected, tmp_path):
     info = TiffImagePlugin.ImageFileDirectory_v2()
 
     tag = TiffTags.TAGS_V2[271]
     assert tag.type == TiffTags.ASCII
 
-    info[271] = b"test"
+    info[271] = value
 
+    im = hopper()
     out = str(tmp_path / "temp.tiff")
     im.save(out, tiffinfo=info)
 
     with Image.open(out) as reloaded:
-        assert reloaded.tag_v2[271] == "test"
+        assert reloaded.tag_v2[271] == expected
 
 
 def test_writing_int_to_bytes(tmp_path):

Tests/test_image_convert.py

@@ -104,6 +104,13 @@ def test_rgba_p():
     assert_image_similar(im, comparable, 20)
 
 
+def test_rgba():
+    with Image.open("Tests/images/transparent.png") as im:
+        assert im.mode == "RGBA"
+
+        assert_image_similar(im.convert("RGBa").convert("RGB"), im.convert("RGB"), 1.5)
+
+
 def test_trns_p(tmp_path):
     im = hopper("P")
     im.info["transparency"] = 0

Tests/test_image_putdata.py

@@ -55,10 +55,11 @@ def test_mode_with_L_with_float():
     assert im.getpixel((0, 0)) == 2
 
 
-def test_mode_i():
+@pytest.mark.parametrize("mode", ("I", "I;16", "I;16L", "I;16B"))
+def test_mode_i(mode):
     src = hopper("L")
     data = list(src.getdata())
-    im = Image.new("I", src.size, 0)
+    im = Image.new(mode, src.size, 0)
     im.putdata(data, 2, 256)
 
     target = [2 * elt + 256 for elt in data]

Tests/test_imagegrab.py

@@ -64,9 +64,13 @@ $bmp = New-Object Drawing.Bitmap 200, 200
             )
             p.communicate()
         else:
-            with pytest.raises(NotImplementedError) as e:
-                ImageGrab.grabclipboard()
-            assert str(e.value) == "ImageGrab.grabclipboard() is macOS and Windows only"
+            if not shutil.which("wl-paste"):
+                with pytest.raises(
+                    NotImplementedError,
+                    match="wl-paste or xclip is required for"
+                    r" ImageGrab.grabclipboard\(\) on Linux",
+                ):
+                    ImageGrab.grabclipboard()
             return
 
         ImageGrab.grabclipboard()

docs/example/DdsImagePlugin.py

@@ -211,13 +211,16 @@ class DdsImageFile(ImageFile.ImageFile):
 
     def _open(self):
         if not _accept(self.fp.read(4)):
-            raise SyntaxError("not a DDS file")
+            msg = "not a DDS file"
+            raise SyntaxError(msg)
         (header_size,) = struct.unpack("<I", self.fp.read(4))
         if header_size != 124:
-            raise OSError(f"Unsupported header size {repr(header_size)}")
+            msg = f"Unsupported header size {repr(header_size)}"
+            raise OSError(msg)
         header_bytes = self.fp.read(header_size - 4)
         if len(header_bytes) != 120:
-            raise OSError(f"Incomplete header: {len(header_bytes)} bytes")
+            msg = f"Incomplete header: {len(header_bytes)} bytes"
+            raise OSError(msg)
         header = BytesIO(header_bytes)
 
         flags, height, width = struct.unpack("<3I", header.read(12))
@@ -237,7 +240,8 @@ class DdsImageFile(ImageFile.ImageFile):
         elif fourcc == b"DXT5":
             self.decoder = "DXT5"
         else:
-            raise NotImplementedError(f"Unimplemented pixel format {fourcc}")
+            msg = f"Unimplemented pixel format {fourcc}"
+            raise NotImplementedError(msg)
 
         self.tile = [(self.decoder, (0, 0) + self.size, 0, (self.mode, 0, 1))]
 
@@ -252,7 +256,8 @@ class DXT1Decoder(ImageFile.PyDecoder):
         try:
             self.set_as_raw(_dxt1(self.fd, self.state.xsize, self.state.ysize))
         except struct.error as e:
-            raise OSError("Truncated DDS file") from e
+            msg = "Truncated DDS file"
+            raise OSError(msg) from e
         return -1, 0
 
 
@@ -263,7 +268,8 @@ class DXT5Decoder(ImageFile.PyDecoder):
         try:
             self.set_as_raw(_dxt5(self.fd, self.state.xsize, self.state.ysize))
         except struct.error as e:
-            raise OSError("Truncated DDS file") from e
+            msg = "Truncated DDS file"
+            raise OSError(msg) from e
         return -1, 0
 
 

docs/handbook/concepts.rst

@@ -64,6 +64,12 @@ Pillow also provides limited support for a few additional modes, including:
     * ``BGR;24`` (24-bit reversed true colour)
     * ``BGR;32`` (32-bit reversed true colour)
 
+Premultiplied alpha is where the values for each other channel have been
+multiplied by the alpha. For example, an RGBA pixel of ``(10, 20, 30, 127)``
+would convert to an RGBa pixel of ``(5, 10, 15, 127)``. The values of the R,
+G and B channels are halved as a result of the half transparency in the alpha
+channel.
+
 Apart from these additional modes, Pillow doesn't yet support multichannel
 images with a depth of more than 8 bits per channel.
 
@@ -111,6 +117,18 @@ the file format handler (see the chapter on :ref:`image-file-formats`). Most
 handlers add properties to the :py:attr:`~PIL.Image.Image.info` attribute when
 loading an image, but ignore it when saving images.
 
+Transparency
+------------
+
+If an image does not have an alpha band, transparency may be specified in the
+:py:attr:`~PIL.Image.Image.info` attribute with a "transparency" key.
+
+Most of the time, the "transparency" value is a single integer, describing
+which pixel value is transparent in a "1", "L", "I" or "P" mode image.
+However, PNG images may have three values, one for each channel in an "RGB"
+mode image, or can have a byte string for a "P" mode image, to specify the
+alpha value for each palette entry.
+
 Orientation
 -----------
 

docs/handbook/image-file-formats.rst

@@ -568,6 +568,11 @@ The :py:meth:`~PIL.Image.Image.save` method supports the following options:
     encoded using RLCP mode will have increasing resolutions decoded as they
     arrive, and so on.
 
+**signed**
+    If true, then tell the encoder to save the image as signed.
+
+    .. versionadded:: 9.4.0
+
 **cinema_mode**
     Set the encoder to produce output compliant with the digital cinema
     specifications.  The options here are ``"no"`` (the default),

docs/handbook/writing-your-own-image-plugin.rst

@@ -78,7 +78,8 @@ true color.
             elif bits == 24:
                 self.mode = "RGB"
             else:
-                raise SyntaxError("unknown number of bits")
+                msg = "unknown number of bits"
+                raise SyntaxError(msg)
 
             # data descriptor
             self.tile = [("raw", (0, 0) + self.size, 128, (self.mode, 0, 1))]

docs/releasenotes/9.4.0.rst

@@ -45,6 +45,12 @@ removes the hidden RGB values for better compression by default in libwebp 0.5
 or later. By setting this option to ``True``, the encoder will keep the hidden
 RGB values.
 
+Added ``signed`` option when saving JPEG2000
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+If the ``signed`` keyword argument is present and true when saving JPEG2000
+images, then tell the encoder to save the image as signed.
+
 Added IFD, Interop and LightSource ExifTags enums
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 

setup.py

@@ -362,15 +362,15 @@ class pil_build_ext(build_ext):
                 self.feature.required.discard(x)
                 _dbg("Disabling %s", x)
                 if getattr(self, f"enable_{x}"):
-                    raise ValueError(
-                        f"Conflicting options: --enable-{x} and --disable-{x}"
-                    )
+                    msg = f"Conflicting options: --enable-{x} and --disable-{x}"
+                    raise ValueError(msg)
                 if x == "freetype":
                     _dbg("--disable-freetype implies --disable-raqm")
                     if getattr(self, "enable_raqm"):
-                        raise ValueError(
+                        msg = (
                             "Conflicting options: --enable-raqm and --disable-freetype"
                         )
+                        raise ValueError(msg)
                     setattr(self, "disable_raqm", True)
             if getattr(self, f"enable_{x}"):
                 _dbg("Requiring %s", x)
@@ -381,13 +381,11 @@ class pil_build_ext(build_ext):
         for x in ("raqm", "fribidi"):
             if getattr(self, f"vendor_{x}"):
                 if getattr(self, "disable_raqm"):
-                    raise ValueError(
-                        f"Conflicting options: --vendor-{x} and --disable-raqm"
-                    )
+                    msg = f"Conflicting options: --vendor-{x} and --disable-raqm"
+                    raise ValueError(msg)
                 if x == "fribidi" and not getattr(self, "vendor_raqm"):
-                    raise ValueError(
-                        f"Conflicting options: --vendor-{x} and not --vendor-raqm"
-                    )
+                    msg = f"Conflicting options: --vendor-{x} and not --vendor-raqm"
+                    raise ValueError(msg)
                 _dbg("Using vendored version of %s", x)
                 self.feature.vendor.add(x)
 

src/PIL/BdfFontFile.py

@@ -86,7 +86,8 @@ class BdfFontFile(FontFile.FontFile):
 
         s = fp.readline()
         if s[:13] != b"STARTFONT 2.1":
-            raise SyntaxError("not a valid BDF file")
+            msg = "not a valid BDF file"
+            raise SyntaxError(msg)
 
         props = {}
         comments = []

src/PIL/BlpImagePlugin.py

@@ -65,7 +65,8 @@ def __getattr__(name):
             if name in enum.__members__:
                 deprecate(f"{prefix}{name}", 10, f"{enum.__name__}.{name}")
                 return enum[name]
-    raise AttributeError(f"module '{__name__}' has no attribute '{name}'")
+    msg = f"module '{__name__}' has no attribute '{name}'"
+    raise AttributeError(msg)
 
 
 def unpack_565(i):
@@ -278,7 +279,8 @@ class BlpImageFile(ImageFile.ImageFile):
         if self.magic in (b"BLP1", b"BLP2"):
             decoder = self.magic.decode()
         else:
-            raise BLPFormatError(f"Bad BLP magic {repr(self.magic)}")
+            msg = f"Bad BLP magic {repr(self.magic)}"
+            raise BLPFormatError(msg)
 
         self.mode = "RGBA" if self._blp_alpha_depth else "RGB"
         self.tile = [(decoder, (0, 0) + self.size, 0, (self.mode, 0, 1))]
@@ -292,7 +294,8 @@ class _BLPBaseDecoder(ImageFile.PyDecoder):
             self._read_blp_header()
             self._load()
         except struct.error as e:
-            raise OSError("Truncated BLP file") from e
+            msg = "Truncated BLP file"
+            raise OSError(msg) from e
         return -1, 0
 
     def _read_blp_header(self):
@@ -354,13 +357,11 @@ class BLP1Decoder(_BLPBaseDecoder):
                 data = self._read_bgra(palette)
                 self.set_as_raw(bytes(data))
             else:
-                raise BLPFormatError(
-                    f"Unsupported BLP encoding {repr(self._blp_encoding)}"
-                )
+                msg = f"Unsupported BLP encoding {repr(self._blp_encoding)}"
+                raise BLPFormatError(msg)
         else:
-            raise BLPFormatError(
-                f"Unsupported BLP compression {repr(self._blp_encoding)}"
-            )
+            msg = f"Unsupported BLP compression {repr(self._blp_encoding)}"
+            raise BLPFormatError(msg)
 
     def _decode_jpeg_stream(self):
         from .JpegImagePlugin import JpegImageFile
@@ -415,16 +416,15 @@ class BLP2Decoder(_BLPBaseDecoder):
                         for d in decode_dxt5(self._safe_read(linesize)):
                             data += d
                 else:
-                    raise BLPFormatError(
-                        f"Unsupported alpha encoding {repr(self._blp_alpha_encoding)}"
-                    )
+                    msg = f"Unsupported alpha encoding {repr(self._blp_alpha_encoding)}"
+                    raise BLPFormatError(msg)
             else:
-                raise BLPFormatError(f"Unknown BLP encoding {repr(self._blp_encoding)}")
+                msg = f"Unknown BLP encoding {repr(self._blp_encoding)}"
+                raise BLPFormatError(msg)
 
         else:
-            raise BLPFormatError(
-                f"Unknown BLP compression {repr(self._blp_compression)}"
-            )
+            msg = f"Unknown BLP compression {repr(self._blp_compression)}"
+            raise BLPFormatError(msg)
 
         self.set_as_raw(bytes(data))
 
@@ -460,7 +460,8 @@ class BLPEncoder(ImageFile.PyEncoder):
 
 def _save(im, fp, filename, save_all=False):
     if im.mode != "P":
-        raise ValueError("Unsupported BLP image mode")
+        msg = "Unsupported BLP image mode"
+        raise ValueError(msg)
 
     magic = b"BLP1" if im.encoderinfo.get("blp_version") == "BLP1" else b"BLP2"
     fp.write(magic)

src/PIL/BmpImagePlugin.py

@@ -146,7 +146,8 @@ class BmpImageFile(ImageFile.ImageFile):
                     file_info["a_mask"],
                 )
         else:
-            raise OSError(f"Unsupported BMP header type ({file_info['header_size']})")
+            msg = f"Unsupported BMP header type ({file_info['header_size']})"
+            raise OSError(msg)
 
         # ------------------ Special case : header is reported 40, which
         # ---------------------- is shorter than real size for bpp >= 16
@@ -164,7 +165,8 @@ class BmpImageFile(ImageFile.ImageFile):
         # ---------------------- Check bit depth for unusual unsupported values
         self.mode, raw_mode = BIT2MODE.get(file_info["bits"], (None, None))
         if self.mode is None:
-            raise OSError(f"Unsupported BMP pixel depth ({file_info['bits']})")
+            msg = f"Unsupported BMP pixel depth ({file_info['bits']})"
+            raise OSError(msg)
 
         # ---------------- Process BMP with Bitfields compression (not palette)
         decoder_name = "raw"
@@ -205,23 +207,27 @@ class BmpImageFile(ImageFile.ImageFile):
                 ):
                     raw_mode = MASK_MODES[(file_info["bits"], file_info["rgb_mask"])]
                 else:
-                    raise OSError("Unsupported BMP bitfields layout")
+                    msg = "Unsupported BMP bitfields layout"
+                    raise OSError(msg)
             else:
-                raise OSError("Unsupported BMP bitfields layout")
+                msg = "Unsupported BMP bitfields layout"
+                raise OSError(msg)
         elif file_info["compression"] == self.RAW:
             if file_info["bits"] == 32 and header == 22:  # 32-bit .cur offset
                 raw_mode, self.mode = "BGRA", "RGBA"
         elif file_info["compression"] in (self.RLE8, self.RLE4):
             decoder_name = "bmp_rle"
         else:
-            raise OSError(f"Unsupported BMP compression ({file_info['compression']})")
+            msg = f"Unsupported BMP compression ({file_info['compression']})"
+            raise OSError(msg)
 
         # --------------- Once the header is processed, process the palette/LUT
         if self.mode == "P":  # Paletted for 1, 4 and 8 bit images
 
             # ---------------------------------------------------- 1-bit images
             if not (0 < file_info["colors"] <= 65536):
-                raise OSError(f"Unsupported BMP Palette size ({file_info['colors']})")
+                msg = f"Unsupported BMP Palette size ({file_info['colors']})"
+                raise OSError(msg)
             else:
                 padding = file_info["palette_padding"]
                 palette = read(padding * file_info["colors"])
@@ -271,7 +277,8 @@ class BmpImageFile(ImageFile.ImageFile):
         head_data = self.fp.read(14)
         # choke if the file does not have the required magic bytes
         if not _accept(head_data):
-            raise SyntaxError("Not a BMP file")
+            msg = "Not a BMP file"
+            raise SyntaxError(msg)
         # read the start position of the BMP image data (u32)
         offset = i32(head_data, 10)
         # load bitmap information (offset=raster info)
@@ -383,7 +390,8 @@ def _save(im, fp, filename, bitmap_header=True):
     try:
         rawmode, bits, colors = SAVE[im.mode]
     except KeyError as e:
-        raise OSError(f"cannot write mode {im.mode} as BMP") from e
+        msg = f"cannot write mode {im.mode} as BMP"
+        raise OSError(msg) from e
 
     info = im.encoderinfo
 
@@ -411,7 +419,8 @@ def _save(im, fp, filename, bitmap_header=True):
         offset = 14 + header + colors * 4
         file_size = offset + image
         if file_size > 2**32 - 1:
-            raise ValueError("File size is too large for the BMP format")
+            msg = "File size is too large for the BMP format"
+            raise ValueError(msg)
         fp.write(
             b"BM"  # file type (magic)
             + o32(file_size)  # file size

src/PIL/BufrStubImagePlugin.py

@@ -42,7 +42,8 @@ class BufrStubImageFile(ImageFile.StubImageFile):
         offset = self.fp.tell()
 
         if not _accept(self.fp.read(4)):
-            raise SyntaxError("Not a BUFR file")
+            msg = "Not a BUFR file"
+            raise SyntaxError(msg)
 
         self.fp.seek(offset)
 
@@ -60,7 +61,8 @@ class BufrStubImageFile(ImageFile.StubImageFile):
 
 def _save(im, fp, filename):
     if _handler is None or not hasattr(_handler, "save"):
-        raise OSError("BUFR save handler not installed")
+        msg = "BUFR save handler not installed"
+        raise OSError(msg)
     _handler.save(im, fp, filename)
 
 

src/PIL/CurImagePlugin.py

@@ -43,7 +43,8 @@ class CurImageFile(BmpImagePlugin.BmpImageFile):
         # check magic
         s = self.fp.read(6)
         if not _accept(s):
-            raise SyntaxError("not a CUR file")
+            msg = "not a CUR file"
+            raise SyntaxError(msg)
 
         # pick the largest cursor in the file
         m = b""
@@ -54,7 +55,8 @@ class CurImageFile(BmpImagePlugin.BmpImageFile):
             elif s[0] > m[0] and s[1] > m[1]:
                 m = s
         if not m:
-            raise TypeError("No cursors were found")
+            msg = "No cursors were found"
+            raise TypeError(msg)
 
         # load as bitmap
         self._bitmap(i32(m, 12) + offset)

src/PIL/DcxImagePlugin.py

@@ -47,7 +47,8 @@ class DcxImageFile(PcxImageFile):
         # Header
         s = self.fp.read(4)
         if not _accept(s):
-            raise SyntaxError("not a DCX file")
+            msg = "not a DCX file"
+            raise SyntaxError(msg)
 
         # Component directory
         self._offset = []

src/PIL/DdsImagePlugin.py

@@ -114,13 +114,16 @@ class DdsImageFile(ImageFile.ImageFile):
 
     def _open(self):
         if not _accept(self.fp.read(4)):
-            raise SyntaxError("not a DDS file")
+            msg = "not a DDS file"
+            raise SyntaxError(msg)
         (header_size,) = struct.unpack("<I", self.fp.read(4))
         if header_size != 124:
-            raise OSError(f"Unsupported header size {repr(header_size)}")
+            msg = f"Unsupported header size {repr(header_size)}"
+            raise OSError(msg)
         header_bytes = self.fp.read(header_size - 4)
         if len(header_bytes) != 120:
-            raise OSError(f"Incomplete header: {len(header_bytes)} bytes")
+            msg = f"Incomplete header: {len(header_bytes)} bytes"
+            raise OSError(msg)
         header = BytesIO(header_bytes)
 
         flags, height, width = struct.unpack("<3I", header.read(12))
@@ -216,11 +219,11 @@ class DdsImageFile(ImageFile.ImageFile):
                         self.info["gamma"] = 1 / 2.2
                     return
                 else:
-                    raise NotImplementedError(
-                        f"Unimplemented DXGI format {dxgi_format}"
-                    )
+                    msg = f"Unimplemented DXGI format {dxgi_format}"
+                    raise NotImplementedError(msg)
             else:
-                raise NotImplementedError(f"Unimplemented pixel format {repr(fourcc)}")
+                msg = f"Unimplemented pixel format {repr(fourcc)}"
+                raise NotImplementedError(msg)
 
             self.tile = [
                 ("bcn", (0, 0) + self.size, data_start, (n, self.pixel_format))
@@ -232,7 +235,8 @@ class DdsImageFile(ImageFile.ImageFile):
 
 def _save(im, fp, filename):
     if im.mode not in ("RGB", "RGBA", "L", "LA"):
-        raise OSError(f"cannot write mode {im.mode} as DDS")
+        msg = f"cannot write mode {im.mode} as DDS"
+        raise OSError(msg)
 
     rawmode = im.mode
     masks = [0xFF0000, 0xFF00, 0xFF]

src/PIL/EpsImagePlugin.py

@@ -133,7 +133,8 @@ def Ghostscript(tile, size, fp, scale=1, transparency=False):
 
     if gs_windows_binary is not None:
         if not gs_windows_binary:
-            raise OSError("Unable to locate Ghostscript on paths")
+            msg = "Unable to locate Ghostscript on paths"
+            raise OSError(msg)
         command[0] = gs_windows_binary
 
     # push data through Ghostscript
@@ -229,12 +230,14 @@ class EpsImageFile(ImageFile.ImageFile):
         while s_raw:
             if s:
                 if len(s) > 255:
-                    raise SyntaxError("not an EPS file")
+                    msg = "not an EPS file"
+                    raise SyntaxError(msg)
 
                 try:
                     m = split.match(s)
                 except re.error as e:
-                    raise SyntaxError("not an EPS file") from e
+                    msg = "not an EPS file"
+                    raise SyntaxError(msg) from e
 
                 if m:
                     k, v = m.group(1, 2)
@@ -268,7 +271,8 @@ class EpsImageFile(ImageFile.ImageFile):
                         # tools mistakenly put in the Comments section
                         pass
                     else:
-                        raise OSError("bad EPS header")
+                        msg = "bad EPS header"
+                        raise OSError(msg)
 
             s_raw = fp.readline()
             s = s_raw.strip("\r\n")
@@ -282,7 +286,8 @@ class EpsImageFile(ImageFile.ImageFile):
         while s[:1] == "%":
 
             if len(s) > 255:
-                raise SyntaxError("not an EPS file")
+                msg = "not an EPS file"
+                raise SyntaxError(msg)
 
             if s[:11] == "%ImageData:":
                 # Encoded bitmapped image.
@@ -306,7 +311,8 @@ class EpsImageFile(ImageFile.ImageFile):
                 break
 
         if not box:
-            raise OSError("cannot determine EPS bounding box")
+            msg = "cannot determine EPS bounding box"
+            raise OSError(msg)
 
     def _find_offset(self, fp):
 
@@ -326,7 +332,8 @@ class EpsImageFile(ImageFile.ImageFile):
             offset = i32(s, 4)
             length = i32(s, 8)
         else:
-            raise SyntaxError("not an EPS file")
+            msg = "not an EPS file"
+            raise SyntaxError(msg)
 
         return length, offset
 
@@ -365,7 +372,8 @@ def _save(im, fp, filename, eps=1):
     elif im.mode == "CMYK":
         operator = (8, 4, b"false 4 colorimage")
     else:
-        raise ValueError("image mode is not supported")
+        msg = "image mode is not supported"
+        raise ValueError(msg)
 
     if eps:
         #

src/PIL/FitsImagePlugin.py

@@ -28,7 +28,8 @@ class FitsImageFile(ImageFile.ImageFile):
         while True:
             header = self.fp.read(80)
             if not header:
-                raise OSError("Truncated FITS file")
+                msg = "Truncated FITS file"
+                raise OSError(msg)
             keyword = header[:8].strip()
             if keyword == b"END":
                 break
@@ -36,12 +37,14 @@ class FitsImageFile(ImageFile.ImageFile):
             if value.startswith(b"="):
                 value = value[1:].strip()
             if not headers and (not _accept(keyword) or value != b"T"):
-                raise SyntaxError("Not a FITS file")
+                msg = "Not a FITS file"
+                raise SyntaxError(msg)
             headers[keyword] = value
 
         naxis = int(headers[b"NAXIS"])
         if naxis == 0:
-            raise ValueError("No image data")
+            msg = "No image data"
+            raise ValueError(msg)
         elif naxis == 1:
             self._size = 1, int(headers[b"NAXIS1"])
         else:

src/PIL/FitsStubImagePlugin.py

@@ -67,7 +67,8 @@ class FITSStubImageFile(ImageFile.StubImageFile):
 
 
 def _save(im, fp, filename):
-    raise OSError("FITS save handler not installed")
+    msg = "FITS save handler not installed"
+    raise OSError(msg)
 
 
 # --------------------------------------------------------------------

src/PIL/FliImagePlugin.py

@@ -50,7 +50,8 @@ class FliImageFile(ImageFile.ImageFile):
         # HEAD
         s = self.fp.read(128)
         if not (_accept(s) and s[20:22] == b"\x00\x00"):
-            raise SyntaxError("not an FLI/FLC file")
+            msg = "not an FLI/FLC file"
+            raise SyntaxError(msg)
 
         # frames
         self.n_frames = i16(s, 6)
@@ -141,7 +142,8 @@ class FliImageFile(ImageFile.ImageFile):
             self.load()
 
         if frame != self.__frame + 1:
-            raise ValueError(f"cannot seek to frame {frame}")
+            msg = f"cannot seek to frame {frame}"
+            raise ValueError(msg)
         self.__frame = frame
 
         # move to next frame

src/PIL/FpxImagePlugin.py

@@ -60,10 +60,12 @@ class FpxImageFile(ImageFile.ImageFile):
         try:
             self.ole = olefile.OleFileIO(self.fp)
         except OSError as e:
-            raise SyntaxError("not an FPX file; invalid OLE file") from e
+            msg = "not an FPX file; invalid OLE file"
+            raise SyntaxError(msg) from e
 
         if self.ole.root.clsid != "56616700-C154-11CE-8553-00AA00A1F95B":
-            raise SyntaxError("not an FPX file; bad root CLSID")
+            msg = "not an FPX file; bad root CLSID"
+            raise SyntaxError(msg)
 
         self._open_index(1)
 
@@ -99,7 +101,8 @@ class FpxImageFile(ImageFile.ImageFile):
         colors = []
         bands = i32(s, 4)
         if bands > 4:
-            raise OSError("Invalid number of bands")
+            msg = "Invalid number of bands"
+            raise OSError(msg)
         for i in range(bands):
             # note: for now, we ignore the "uncalibrated" flag
             colors.append(i32(s, 8 + i * 4) & 0x7FFFFFFF)
@@ -141,7 +144,8 @@ class FpxImageFile(ImageFile.ImageFile):
         length = i32(s, 32)
 
         if size != self.size:
-            raise OSError("subimage mismatch")
+            msg = "subimage mismatch"
+            raise OSError(msg)
 
         # get tile descriptors
         fp.seek(28 + offset)
@@ -217,7 +221,8 @@ class FpxImageFile(ImageFile.ImageFile):
                     self.tile_prefix = self.jpeg[jpeg_tables]
 
             else:
-                raise OSError("unknown/invalid compression")
+                msg = "unknown/invalid compression"
+                raise OSError(msg)
 
             x = x + xtile
             if x >= xsize:

src/PIL/FtexImagePlugin.py

@@ -73,7 +73,8 @@ def __getattr__(name):
             if name in enum.__members__:
                 deprecate(f"{prefix}{name}", 10, f"{enum.__name__}.{name}")
                 return enum[name]
-    raise AttributeError(f"module '{__name__}' has no attribute '{name}'")
+    msg = f"module '{__name__}' has no attribute '{name}'"
+    raise AttributeError(msg)
 
 
 class FtexImageFile(ImageFile.ImageFile):
@@ -82,7 +83,8 @@ class FtexImageFile(ImageFile.ImageFile):
 
     def _open(self):
         if not _accept(self.fp.read(4)):
-            raise SyntaxError("not an FTEX file")
+            msg = "not an FTEX file"
+            raise SyntaxError(msg)
         struct.unpack("<i", self.fp.read(4))  # version
         self._size = struct.unpack("<2i", self.fp.read(8))
         mipmap_count, format_count = struct.unpack("<2i", self.fp.read(8))
@@ -105,7 +107,8 @@ class FtexImageFile(ImageFile.ImageFile):
         elif format == Format.UNCOMPRESSED:
             self.tile = [("raw", (0, 0) + self.size, 0, ("RGB", 0, 1))]
         else:
-            raise ValueError(f"Invalid texture compression format: {repr(format)}")
+            msg = f"Invalid texture compression format: {repr(format)}"
+            raise ValueError(msg)
 
         self.fp.close()
         self.fp = BytesIO(data)

src/PIL/GbrImagePlugin.py

@@ -44,18 +44,22 @@ class GbrImageFile(ImageFile.ImageFile):
     def _open(self):
         header_size = i32(self.fp.read(4))
         if header_size < 20:
-            raise SyntaxError("not a GIMP brush")
+            msg = "not a GIMP brush"
+            raise SyntaxError(msg)
         version = i32(self.fp.read(4))
         if version not in (1, 2):
-            raise SyntaxError(f"Unsupported GIMP brush version: {version}")
+            msg = f"Unsupported GIMP brush version: {version}"
+            raise SyntaxError(msg)
 
         width = i32(self.fp.read(4))
         height = i32(self.fp.read(4))
         color_depth = i32(self.fp.read(4))
         if width <= 0 or height <= 0:
-            raise SyntaxError("not a GIMP brush")
+            msg = "not a GIMP brush"
+            raise SyntaxError(msg)
         if color_depth not in (1, 4):
-            raise SyntaxError(f"Unsupported GIMP brush color depth: {color_depth}")
+            msg = f"Unsupported GIMP brush color depth: {color_depth}"
+            raise SyntaxError(msg)
 
         if version == 1:
             comment_length = header_size - 20
@@ -63,7 +67,8 @@ class GbrImageFile(ImageFile.ImageFile):
             comment_length = header_size - 28
             magic_number = self.fp.read(4)
             if magic_number != b"GIMP":
-                raise SyntaxError("not a GIMP brush, bad magic number")
+                msg = "not a GIMP brush, bad magic number"
+                raise SyntaxError(msg)
             self.info["spacing"] = i32(self.fp.read(4))
 
         comment = self.fp.read(comment_length)[:-1]

src/PIL/GdImageFile.py

@@ -49,7 +49,8 @@ class GdImageFile(ImageFile.ImageFile):
         s = self.fp.read(1037)
 
         if not i16(s) in [65534, 65535]:
-            raise SyntaxError("Not a valid GD 2.x .gd file")
+            msg = "Not a valid GD 2.x .gd file"
+            raise SyntaxError(msg)
 
         self.mode = "L"  # FIXME: "P"
         self._size = i16(s, 2), i16(s, 4)
@@ -87,9 +88,11 @@ def open(fp, mode="r"):
     :raises OSError: If the image could not be read.
     """
     if mode != "r":
-        raise ValueError("bad mode")
+        msg = "bad mode"
+        raise ValueError(msg)
 
     try:
         return GdImageFile(fp)
     except SyntaxError as e:
-        raise UnidentifiedImageError("cannot identify this image file") from e
+        msg = "cannot identify this image file"
+        raise UnidentifiedImageError(msg) from e

src/PIL/GifImagePlugin.py

@@ -85,7 +85,8 @@ class GifImageFile(ImageFile.ImageFile):
         # Screen
         s = self.fp.read(13)
         if not _accept(s):
-            raise SyntaxError("not a GIF file")
+            msg = "not a GIF file"
+            raise SyntaxError(msg)
 
         self.info["version"] = s[:6]
         self._size = i16(s, 6), i16(s, 8)
@@ -152,7 +153,8 @@ class GifImageFile(ImageFile.ImageFile):
                 self._seek(f)
             except EOFError as e:
                 self.seek(last_frame)
-                raise EOFError("no more images in GIF file") from e
+                msg = "no more images in GIF file"
+                raise EOFError(msg) from e
 
     def _seek(self, frame, update_image=True):
 
@@ -171,7 +173,8 @@ class GifImageFile(ImageFile.ImageFile):
                 self.load()
 
         if frame != self.__frame + 1:
-            raise ValueError(f"cannot seek to frame {frame}")
+            msg = f"cannot seek to frame {frame}"
+            raise ValueError(msg)
 
         self.fp = self._fp
         if self.__offset:

src/PIL/GimpGradientFile.py

@@ -107,7 +107,8 @@ class GimpGradientFile(GradientFile):
     def __init__(self, fp):
 
         if fp.readline()[:13] != b"GIMP Gradient":
-            raise SyntaxError("not a GIMP gradient file")
+            msg = "not a GIMP gradient file"
+            raise SyntaxError(msg)
 
         line = fp.readline()
 
@@ -133,7 +134,8 @@ class GimpGradientFile(GradientFile):
             cspace = int(s[12])
 
             if cspace != 0:
-                raise OSError("cannot handle HSV colour space")
+                msg = "cannot handle HSV colour space"
+                raise OSError(msg)
 
             gradient.append((x0, x1, xm, rgb0, rgb1, segment))
 

src/PIL/GimpPaletteFile.py

@@ -29,7 +29,8 @@ class GimpPaletteFile:
         self.palette = [o8(i) * 3 for i in range(256)]
 
         if fp.readline()[:12] != b"GIMP Palette":
-            raise SyntaxError("not a GIMP palette file")
+            msg = "not a GIMP palette file"
+            raise SyntaxError(msg)
 
         for i in range(256):
 
@@ -41,11 +42,13 @@ class GimpPaletteFile:
             if re.match(rb"\w+:|#", s):
                 continue
             if len(s) > 100:
-                raise SyntaxError("bad palette file")
+                msg = "bad palette file"
+                raise SyntaxError(msg)
 
             v = tuple(map(int, s.split()[:3]))
             if len(v) != 3:
-                raise ValueError("bad palette entry")
+                msg = "bad palette entry"
+                raise ValueError(msg)
 
             self.palette[i] = o8(v[0]) + o8(v[1]) + o8(v[2])
 

src/PIL/GribStubImagePlugin.py

@@ -42,7 +42,8 @@ class GribStubImageFile(ImageFile.StubImageFile):
         offset = self.fp.tell()
 
         if not _accept(self.fp.read(8)):
-            raise SyntaxError("Not a GRIB file")
+            msg = "Not a GRIB file"
+            raise SyntaxError(msg)
 
         self.fp.seek(offset)
 
@@ -60,7 +61,8 @@ class GribStubImageFile(ImageFile.StubImageFile):
 
 def _save(im, fp, filename):
     if _handler is None or not hasattr(_handler, "save"):
-        raise OSError("GRIB save handler not installed")
+        msg = "GRIB save handler not installed"
+        raise OSError(msg)
     _handler.save(im, fp, filename)
 
 

src/PIL/Hdf5StubImagePlugin.py

@@ -42,7 +42,8 @@ class HDF5StubImageFile(ImageFile.StubImageFile):
         offset = self.fp.tell()
 
         if not _accept(self.fp.read(8)):
-            raise SyntaxError("Not an HDF file")
+            msg = "Not an HDF file"
+            raise SyntaxError(msg)
 
         self.fp.seek(offset)
 
@@ -60,7 +61,8 @@ class HDF5StubImageFile(ImageFile.StubImageFile):
 
 def _save(im, fp, filename):
     if _handler is None or not hasattr(_handler, "save"):
-        raise OSError("HDF5 save handler not installed")
+        msg = "HDF5 save handler not installed"
+        raise OSError(msg)
     _handler.save(im, fp, filename)
 
 

src/PIL/IcnsImagePlugin.py

@@ -42,7 +42,8 @@ def read_32t(fobj, start_length, size):
     fobj.seek(start)
     sig = fobj.read(4)
     if sig != b"\x00\x00\x00\x00":
-        raise SyntaxError("Unknown signature, expecting 0x00000000")
+        msg = "Unknown signature, expecting 0x00000000"
+        raise SyntaxError(msg)
     return read_32(fobj, (start + 4, length - 4), size)
 
 
@@ -82,7 +83,8 @@ def read_32(fobj, start_length, size):
                 if bytesleft <= 0:
                     break
             if bytesleft != 0:
-                raise SyntaxError(f"Error reading channel [{repr(bytesleft)} left]")
+                msg = f"Error reading channel [{repr(bytesleft)} left]"
+                raise SyntaxError(msg)
             band = Image.frombuffer("L", pixel_size, b"".join(data), "raw", "L", 0, 1)
             im.im.putband(band.im, band_ix)
     return {"RGB": im}
@@ -113,10 +115,11 @@ def read_png_or_jpeg2000(fobj, start_length, size):
         or sig == b"\x00\x00\x00\x0cjP  \x0d\x0a\x87\x0a"
     ):
         if not enable_jpeg2k:
-            raise ValueError(
+            msg = (
                 "Unsupported icon subimage format (rebuild PIL "
                 "with JPEG 2000 support to fix this)"
             )
+            raise ValueError(msg)
         # j2k, jpc or j2c
         fobj.seek(start)
         jp2kstream = fobj.read(length)
@@ -127,7 +130,8 @@ def read_png_or_jpeg2000(fobj, start_length, size):
             im = im.convert("RGBA")
         return {"RGBA": im}
     else:
-        raise ValueError("Unsupported icon subimage format")
+        msg = "Unsupported icon subimage format"
+        raise ValueError(msg)
 
 
 class IcnsFile:
@@ -168,12 +172,14 @@ class IcnsFile:
         self.fobj = fobj
         sig, filesize = nextheader(fobj)
         if not _accept(sig):
-            raise SyntaxError("not an icns file")
+            msg = "not an icns file"
+            raise SyntaxError(msg)
         i = HEADERSIZE
         while i < filesize:
             sig, blocksize = nextheader(fobj)
             if blocksize <= 0:
-                raise SyntaxError("invalid block header")
+                msg = "invalid block header"
+                raise SyntaxError(msg)
             i += HEADERSIZE
             blocksize -= HEADERSIZE
             dct[sig] = (i, blocksize)
@@ -192,7 +198,8 @@ class IcnsFile:
     def bestsize(self):
         sizes = self.itersizes()
         if not sizes:
-            raise SyntaxError("No 32bit icon resources found")
+            msg = "No 32bit icon resources found"
+            raise SyntaxError(msg)
         return max(sizes)
 
     def dataforsize(self, size):
@@ -275,7 +282,8 @@ class IcnsImageFile(ImageFile.ImageFile):
             if value in simple_sizes:
                 info_size = self.info["sizes"][simple_sizes.index(value)]
         if info_size not in self.info["sizes"]:
-            raise ValueError("This is not one of the allowed sizes of this image")
+            msg = "This is not one of the allowed sizes of this image"
+            raise ValueError(msg)
         self._size = value
 
     def load(self):

src/PIL/IcoImagePlugin.py

@@ -127,7 +127,8 @@ class IcoFile:
         # check magic
         s = buf.read(6)
         if not _accept(s):
-            raise SyntaxError("not an ICO file")
+            msg = "not an ICO file"
+            raise SyntaxError(msg)
 
         self.buf = buf
         self.entry = []
@@ -316,7 +317,8 @@ class IcoImageFile(ImageFile.ImageFile):
     @size.setter
     def size(self, value):
         if value not in self.info["sizes"]:
-            raise ValueError("This is not one of the allowed sizes of this image")
+            msg = "This is not one of the allowed sizes of this image"
+            raise ValueError(msg)
         self._size = value
 
     def load(self):

src/PIL/ImImagePlugin.py

@@ -126,7 +126,8 @@ class ImImageFile(ImageFile.ImageFile):
         # 100 bytes, this is (probably) not a text header.
 
         if b"\n" not in self.fp.read(100):
-            raise SyntaxError("not an IM file")
+            msg = "not an IM file"
+            raise SyntaxError(msg)
         self.fp.seek(0)
 
         n = 0
@@ -153,7 +154,8 @@ class ImImageFile(ImageFile.ImageFile):
             s = s + self.fp.readline()
 
             if len(s) > 100:
-                raise SyntaxError("not an IM file")
+                msg = "not an IM file"
+                raise SyntaxError(msg)
 
             if s[-2:] == b"\r\n":
                 s = s[:-2]
@@ -163,7 +165,8 @@ class ImImageFile(ImageFile.ImageFile):
             try:
                 m = split.match(s)
             except re.error as e:
-                raise SyntaxError("not an IM file") from e
+                msg = "not an IM file"
+                raise SyntaxError(msg) from e
 
             if m:
 
@@ -198,12 +201,12 @@ class ImImageFile(ImageFile.ImageFile):
 
             else:
 
-                raise SyntaxError(
-                    "Syntax error in IM header: " + s.decode("ascii", "replace")
-                )
+                msg = "Syntax error in IM header: " + s.decode("ascii", "replace")
+                raise SyntaxError(msg)
 
         if not n:
-            raise SyntaxError("Not an IM file")
+            msg = "Not an IM file"
+            raise SyntaxError(msg)
 
         # Basic attributes
         self._size = self.info[SIZE]
@@ -213,7 +216,8 @@ class ImImageFile(ImageFile.ImageFile):
         while s and s[:1] != b"\x1A":
             s = self.fp.read(1)
         if not s:
-            raise SyntaxError("File truncated")
+            msg = "File truncated"
+            raise SyntaxError(msg)
 
         if LUT in self.info:
             # convert lookup table to palette or lut attribute
@@ -332,7 +336,8 @@ def _save(im, fp, filename):
     try:
         image_type, rawmode = SAVE[im.mode]
     except KeyError as e:
-        raise ValueError(f"Cannot save {im.mode} images as IM") from e
+        msg = f"Cannot save {im.mode} images as IM"
+        raise ValueError(msg) from e
 
     frames = im.encoderinfo.get("frames", 1)
 

src/PIL/Image.py

@@ -75,7 +75,8 @@ def __getattr__(name):
             name, 10, f"{old_resampling[name]} or Resampling.{old_resampling[name]}"
         )
         return Resampling[old_resampling[name]]
-    raise AttributeError(f"module '{__name__}' has no attribute '{name}'")
+    msg = f"module '{__name__}' has no attribute '{name}'"
+    raise AttributeError(msg)
 
 
 logger = logging.getLogger(__name__)
@@ -102,11 +103,12 @@ try:
     from . import _imaging as core
 
     if __version__ != getattr(core, "PILLOW_VERSION", None):
-        raise ImportError(
+        msg = (
             "The _imaging extension was built for another version of Pillow or PIL:\n"
             f"Core version: {getattr(core, 'PILLOW_VERSION', None)}\n"
             f"Pillow version: {__version__}"
         )
+        raise ImportError(msg)
 
 except ImportError as v:
     core = DeferredError(ImportError("The _imaging C module is not installed."))
@@ -407,7 +409,8 @@ def _getdecoder(mode, decoder_name, args, extra=()):
         # get decoder
         decoder = getattr(core, decoder_name + "_decoder")
     except AttributeError as e:
-        raise OSError(f"decoder {decoder_name} not available") from e
+        msg = f"decoder {decoder_name} not available"
+        raise OSError(msg) from e
     return decoder(mode, *args + extra)
 
 
@@ -430,7 +433,8 @@ def _getencoder(mode, encoder_name, args, extra=()):
         # get encoder
         encoder = getattr(core, encoder_name + "_encoder")
     except AttributeError as e:
-        raise OSError(f"encoder {encoder_name} not available") from e
+        msg = f"encoder {encoder_name} not available"
+        raise OSError(msg) from e
     return encoder(mode, *args + extra)
 
 
@@ -676,7 +680,8 @@ class Image:
         try:
             self.save(b, "PNG")
         except Exception as e:
-            raise ValueError("Could not save to PNG for display") from e
+            msg = "Could not save to PNG for display"
+            raise ValueError(msg) from e
         return b.getvalue()
 
     @property
@@ -768,7 +773,8 @@ class Image:
             if s:
                 break
         if s < 0:
-            raise RuntimeError(f"encoder error {s} in tobytes")
+            msg = f"encoder error {s} in tobytes"
+            raise RuntimeError(msg)
 
         return b"".join(data)
 
@@ -785,7 +791,8 @@ class Image:
 
         self.load()
         if self.mode != "1":
-            raise ValueError("not a bitmap")
+            msg = "not a bitmap"
+            raise ValueError(msg)
         data = self.tobytes("xbm")
         return b"".join(
             [
@@ -819,9 +826,11 @@ class Image:
         s = d.decode(data)
 
         if s[0] >= 0:
-            raise ValueError("not enough image data")
+            msg = "not enough image data"
+            raise ValueError(msg)
         if s[1] != 0:
-            raise ValueError("cannot decode image data")
+            msg = "cannot decode image data"
+            raise ValueError(msg)
 
     def load(self):
         """
@@ -942,7 +951,8 @@ class Image:
         if matrix:
             # matrix conversion
             if mode not in ("L", "RGB"):
-                raise ValueError("illegal conversion")
+                msg = "illegal conversion"
+                raise ValueError(msg)
             im = self.im.convert_matrix(mode, matrix)
             new = self._new(im)
             if has_transparency and self.im.bands == 3:
@@ -1027,7 +1037,8 @@ class Image:
                 elif isinstance(t, int):
                     self.im.putpalettealpha(t, 0)
                 else:
-                    raise ValueError("Transparency for P mode should be bytes or int")
+                    msg = "Transparency for P mode should be bytes or int"
+                    raise ValueError(msg)
 
         if mode == "P" and palette == Palette.ADAPTIVE:
             im = self.im.quantize(colors)
@@ -1077,7 +1088,8 @@ class Image:
                 im = self.im.convert(modebase)
                 im = im.convert(mode, dither)
             except KeyError as e:
-                raise ValueError("illegal conversion") from e
+                msg = "illegal conversion"
+                raise ValueError(msg) from e
 
         new_im = self._new(im)
         if mode == "P" and palette != Palette.ADAPTIVE:
@@ -1152,20 +1164,21 @@ class Image:
             Quantize.LIBIMAGEQUANT,
         ):
             # Caller specified an invalid mode.
-            raise ValueError(
+            msg = (
                 "Fast Octree (method == 2) and libimagequant (method == 3) "
                 "are the only valid methods for quantizing RGBA images"
             )
+            raise ValueError(msg)
 
         if palette:
             # use palette from reference image
             palette.load()
             if palette.mode != "P":
-                raise ValueError("bad mode for palette image")
+                msg = "bad mode for palette image"
+                raise ValueError(msg)
             if self.mode != "RGB" and self.mode != "L":
-                raise ValueError(
-                    "only RGB or L mode images can be quantized to a palette"
-                )
+                msg = "only RGB or L mode images can be quantized to a palette"
+                raise ValueError(msg)
             im = self.im.convert("P", dither, palette.im)
             new_im = self._new(im)
             new_im.palette = palette.palette.copy()
@@ -1211,9 +1224,11 @@ class Image:
             return self.copy()
 
         if box[2] < box[0]:
-            raise ValueError("Coordinate 'right' is less than 'left'")
+            msg = "Coordinate 'right' is less than 'left'"
+            raise ValueError(msg)
         elif box[3] < box[1]:
-            raise ValueError("Coordinate 'lower' is less than 'upper'")
+            msg = "Coordinate 'lower' is less than 'upper'"
+            raise ValueError(msg)
 
         self.load()
         return self._new(self._crop(self.im, box))
@@ -1281,9 +1296,8 @@ class Image:
         if isinstance(filter, Callable):
             filter = filter()
         if not hasattr(filter, "filter"):
-            raise TypeError(
-                "filter argument should be ImageFilter.Filter instance or class"
-            )
+            msg = "filter argument should be ImageFilter.Filter instance or class"
+            raise TypeError(msg)
 
         multiband = isinstance(filter, ImageFilter.MultibandFilter)
         if self.im.bands == 1 or multiband:
@@ -1532,7 +1546,8 @@ class Image:
     def apply_transparency(self):
         """
         If a P mode image has a "transparency" key in the info dictionary,
-        remove the key and apply the transparency to the palette instead.
+        remove the key and instead apply the transparency to the palette.
+        Otherwise, the image is unchanged.
         """
         if self.mode != "P" or "transparency" not in self.info:
             return
@@ -1691,7 +1706,8 @@ class Image:
                 size = mask.size
             else:
                 # FIXME: use self.size here?
-                raise ValueError("cannot determine region size; use 4-item box")
+                msg = "cannot determine region size; use 4-item box"
+                raise ValueError(msg)
             box += (box[0] + size[0], box[1] + size[1])
 
         if isinstance(im, str):
@@ -1730,15 +1746,20 @@ class Image:
         """
 
         if not isinstance(source, (list, tuple)):
-            raise ValueError("Source must be a tuple")
+            msg = "Source must be a tuple"
+            raise ValueError(msg)
         if not isinstance(dest, (list, tuple)):
-            raise ValueError("Destination must be a tuple")
+            msg = "Destination must be a tuple"
+            raise ValueError(msg)
         if not len(source) in (2, 4):
-            raise ValueError("Source must be a 2 or 4-tuple")
+            msg = "Source must be a 2 or 4-tuple"
+            raise ValueError(msg)
         if not len(dest) == 2:
-            raise ValueError("Destination must be a 2-tuple")
+            msg = "Destination must be a 2-tuple"
+            raise ValueError(msg)
         if min(source) < 0:
-            raise ValueError("Source must be non-negative")
+            msg = "Source must be non-negative"
+            raise ValueError(msg)
 
         if len(source) == 2:
             source = source + im.size
@@ -1803,7 +1824,8 @@ class Image:
 
         if self.mode == "F":
             # FIXME: _imaging returns a confusing error message for this case
-            raise ValueError("point operation not supported for this mode")
+            msg = "point operation not supported for this mode"
+            raise ValueError(msg)
 
         if mode != "F":
             lut = [round(i) for i in lut]
@@ -1837,7 +1859,8 @@ class Image:
                 self.pyaccess = None
                 self.mode = self.im.mode
             except KeyError as e:
-                raise ValueError("illegal image mode") from e
+                msg = "illegal image mode"
+                raise ValueError(msg) from e
 
         if self.mode in ("LA", "PA"):
             band = 1
@@ -1847,7 +1870,8 @@ class Image:
         if isImageType(alpha):
             # alpha layer
             if alpha.mode not in ("1", "L"):
-                raise ValueError("illegal image mode")
+                msg = "illegal image mode"
+                raise ValueError(msg)
             alpha.load()
             if alpha.mode == "1":
                 alpha = alpha.convert("L")
@@ -1903,7 +1927,8 @@ class Image:
         from . import ImagePalette
 
         if self.mode not in ("L", "LA", "P", "PA"):
-            raise ValueError("illegal image mode")
+            msg = "illegal image mode"
+            raise ValueError(msg)
         if isinstance(data, ImagePalette.ImagePalette):
             palette = ImagePalette.raw(data.rawmode, data.palette)
         else:
@@ -1972,7 +1997,8 @@ class Image:
         from . import ImagePalette
 
         if self.mode not in ("L", "P"):
-            raise ValueError("illegal image mode")
+            msg = "illegal image mode"
+            raise ValueError(msg)
 
         bands = 3
         palette_mode = "RGB"
@@ -2104,7 +2130,7 @@ class Image:
             Resampling.BOX,
             Resampling.HAMMING,
         ):
-            message = f"Unknown resampling filter ({resample})."
+            msg = f"Unknown resampling filter ({resample})."
 
             filters = [
                 f"{filter[1]} ({filter[0]})"
@@ -2117,12 +2143,12 @@ class Image:
                     (Resampling.HAMMING, "Image.Resampling.HAMMING"),
                 )
             ]
-            raise ValueError(
-                message + " Use " + ", ".join(filters[:-1]) + " or " + filters[-1]
-            )
+            msg += " Use " + ", ".join(filters[:-1]) + " or " + filters[-1]
+            raise ValueError(msg)
 
         if reducing_gap is not None and reducing_gap < 1.0:
-            raise ValueError("reducing_gap must be 1.0 or greater")
+            msg = "reducing_gap must be 1.0 or greater"
+            raise ValueError(msg)
 
         size = tuple(size)
 
@@ -2380,7 +2406,8 @@ class Image:
             try:
                 format = EXTENSION[ext]
             except KeyError as e:
-                raise ValueError(f"unknown file extension: {ext}") from e
+                msg = f"unknown file extension: {ext}"
+                raise ValueError(msg) from e
 
         if format.upper() not in SAVE:
             init()
@@ -2494,7 +2521,8 @@ class Image:
             try:
                 channel = self.getbands().index(channel)
             except ValueError as e:
-                raise ValueError(f'The image has no channel "{channel}"') from e
+                msg = f'The image has no channel "{channel}"'
+                raise ValueError(msg) from e
 
         return self._new(self.im.getband(channel))
 
@@ -2665,7 +2693,8 @@ class Image:
             method, data = method.getdata()
 
         if data is None:
-            raise ValueError("missing method data")
+            msg = "missing method data"
+            raise ValueError(msg)
 
         im = new(self.mode, size, fillcolor)
         if self.mode == "P" and self.palette:
@@ -2726,7 +2755,8 @@ class Image:
             )
 
         else:
-            raise ValueError("unknown transformation method")
+            msg = "unknown transformation method"
+            raise ValueError(msg)
 
         if resample not in (
             Resampling.NEAREST,
@@ -2734,13 +2764,13 @@ class Image:
             Resampling.BICUBIC,
         ):
             if resample in (Resampling.BOX, Resampling.HAMMING, Resampling.LANCZOS):
-                message = {
+                msg = {
                     Resampling.BOX: "Image.Resampling.BOX",
                     Resampling.HAMMING: "Image.Resampling.HAMMING",
                     Resampling.LANCZOS: "Image.Resampling.LANCZOS",
                 }[resample] + f" ({resample}) cannot be used."
             else:
-                message = f"Unknown resampling filter ({resample})."
+                msg = f"Unknown resampling filter ({resample})."
 
             filters = [
                 f"{filter[1]} ({filter[0]})"
@@ -2750,9 +2780,8 @@ class Image:
                     (Resampling.BICUBIC, "Image.Resampling.BICUBIC"),
                 )
             ]
-            raise ValueError(
-                message + " Use " + ", ".join(filters[:-1]) + " or " + filters[-1]
-            )
+            msg += " Use " + ", ".join(filters[:-1]) + " or " + filters[-1]
+            raise ValueError(msg)
 
         image.load()
 
@@ -2791,7 +2820,8 @@ class Image:
         from . import ImageQt
 
         if not ImageQt.qt_is_installed:
-            raise ImportError("Qt bindings are not installed")
+            msg = "Qt bindings are not installed"
+            raise ImportError(msg)
         return ImageQt.toqimage(self)
 
     def toqpixmap(self):
@@ -2799,7 +2829,8 @@ class Image:
         from . import ImageQt
 
         if not ImageQt.qt_is_installed:
-            raise ImportError("Qt bindings are not installed")
+            msg = "Qt bindings are not installed"
+            raise ImportError(msg)
         return ImageQt.toqpixmap(self)
 
 
@@ -2847,11 +2878,14 @@ def _check_size(size):
     """
 
     if not isinstance(size, (list, tuple)):
-        raise ValueError("Size must be a tuple")
+        msg = "Size must be a tuple"
+        raise ValueError(msg)
     if len(size) != 2:
-        raise ValueError("Size must be a tuple of length 2")
+        msg = "Size must be a tuple of length 2"
+        raise ValueError(msg)
     if size[0] < 0 or size[1] < 0:
-        raise ValueError("Width and height must be >= 0")
+        msg = "Width and height must be >= 0"
+        raise ValueError(msg)
 
     return True
 
@@ -3037,11 +3071,13 @@ def fromarray(obj, mode=None):
         try:
             typekey = (1, 1) + shape[2:], arr["typestr"]
         except KeyError as e:
-            raise TypeError("Cannot handle this data type") from e
+            msg = "Cannot handle this data type"
+            raise TypeError(msg) from e
         try:
             mode, rawmode = _fromarray_typemap[typekey]
         except KeyError as e:
-            raise TypeError("Cannot handle this data type: %s, %s" % typekey) from e
+            msg = "Cannot handle this data type: %s, %s" % typekey
+            raise TypeError(msg) from e
     else:
         rawmode = mode
     if mode in ["1", "L", "I", "P", "F"]:
@@ -3051,7 +3087,8 @@ def fromarray(obj, mode=None):
     else:
         ndmax = 4
     if ndim > ndmax:
-        raise ValueError(f"Too many dimensions: {ndim} > {ndmax}.")
+        msg = f"Too many dimensions: {ndim} > {ndmax}."
+        raise ValueError(msg)
 
     size = 1 if ndim == 1 else shape[1], shape[0]
     if strides is not None:
@@ -3068,7 +3105,8 @@ def fromqimage(im):
     from . import ImageQt
 
     if not ImageQt.qt_is_installed:
-        raise ImportError("Qt bindings are not installed")
+        msg = "Qt bindings are not installed"
+        raise ImportError(msg)
     return ImageQt.fromqimage(im)
 
 
@@ -3077,7 +3115,8 @@ def fromqpixmap(im):
     from . import ImageQt
 
     if not ImageQt.qt_is_installed:
-        raise ImportError("Qt bindings are not installed")
+        msg = "Qt bindings are not installed"
+        raise ImportError(msg)
     return ImageQt.fromqpixmap(im)
 
 
@@ -3115,10 +3154,11 @@ def _decompression_bomb_check(size):
     pixels = size[0] * size[1]
 
     if pixels > 2 * MAX_IMAGE_PIXELS:
-        raise DecompressionBombError(
+        msg = (
             f"Image size ({pixels} pixels) exceeds limit of {2 * MAX_IMAGE_PIXELS} "
             "pixels, could be decompression bomb DOS attack."
         )
+        raise DecompressionBombError(msg)
 
     if pixels > MAX_IMAGE_PIXELS:
         warnings.warn(
@@ -3158,17 +3198,20 @@ def open(fp, mode="r", formats=None):
     """
 
     if mode != "r":
-        raise ValueError(f"bad mode {repr(mode)}")
+        msg = f"bad mode {repr(mode)}"
+        raise ValueError(msg)
     elif isinstance(fp, io.StringIO):
-        raise ValueError(
+        msg = (
             "StringIO cannot be used to open an image. "
             "Binary data must be used instead."
         )
+        raise ValueError(msg)
 
     if formats is None:
         formats = ID
     elif not isinstance(formats, (list, tuple)):
-        raise TypeError("formats must be a list or tuple")
+        msg = "formats must be a list or tuple"
+        raise TypeError(msg)
 
     exclusive_fp = False
     filename = ""
@@ -3233,9 +3276,8 @@ def open(fp, mode="r", formats=None):
         fp.close()
     for message in accept_warnings:
         warnings.warn(message)
-    raise UnidentifiedImageError(
-        "cannot identify image file %r" % (filename if filename else fp)
-    )
+    msg = "cannot identify image file %r" % (filename if filename else fp)
+    raise UnidentifiedImageError(msg)
 
 
 #
@@ -3326,12 +3368,15 @@ def merge(mode, bands):
     """
 
     if getmodebands(mode) != len(bands) or "*" in mode:
-        raise ValueError("wrong number of bands")
+        msg = "wrong number of bands"
+        raise ValueError(msg)
     for band in bands[1:]:
         if band.mode != getmodetype(mode):
-            raise ValueError("mode mismatch")
+            msg = "mode mismatch"
+            raise ValueError(msg)
         if band.size != bands[0].size:
-            raise ValueError("size mismatch")
+            msg = "size mismatch"
+            raise ValueError(msg)
     for band in bands:
         band.load()
     return bands[0]._new(core.merge(mode, *[b.im for b in bands]))
@@ -3687,7 +3732,7 @@ class Exif(MutableMapping):
     def get_ifd(self, tag):
         if tag not in self._ifds:
             if tag == ExifTags.IFD.IFD1:
-                if self._info is not None:
+                if self._info is not None and self._info.next != 0:
                     self._ifds[tag] = self._get_ifd_dict(self._info.next)
             elif tag in [ExifTags.IFD.Exif, ExifTags.IFD.GPSInfo]:
                 offset = self._hidden_data.get(tag, self.get(tag))

src/PIL/ImageCms.py

@@ -124,7 +124,8 @@ def __getattr__(name):
             if name in enum.__members__:
                 deprecate(f"{prefix}{name}", 10, f"{enum.__name__}.{name}")
                 return enum[name]
-    raise AttributeError(f"module '{__name__}' has no attribute '{name}'")
+    msg = f"module '{__name__}' has no attribute '{name}'"
+    raise AttributeError(msg)
 
 
 #
@@ -191,7 +192,8 @@ class ImageCmsProfile:
         elif isinstance(profile, _imagingcms.CmsProfile):
             self._set(profile)
         else:
-            raise TypeError("Invalid type for Profile")
+            msg = "Invalid type for Profile"
+            raise TypeError(msg)
 
     def _set(self, profile, filename=None):
         self.profile = profile
@@ -269,7 +271,8 @@ class ImageCmsTransform(Image.ImagePointHandler):
     def apply_in_place(self, im):
         im.load()
         if im.mode != self.output_mode:
-            raise ValueError("mode mismatch")  # wrong output mode
+            msg = "mode mismatch"
+            raise ValueError(msg)  # wrong output mode
         self.transform.apply(im.im.id, im.im.id)
         im.info["icc_profile"] = self.output_profile.tobytes()
         return im
@@ -374,10 +377,12 @@ def profileToProfile(
         outputMode = im.mode
 
     if not isinstance(renderingIntent, int) or not (0 <= renderingIntent <= 3):
-        raise PyCMSError("renderingIntent must be an integer between 0 and 3")
+        msg = "renderingIntent must be an integer between 0 and 3"
+        raise PyCMSError(msg)
 
     if not isinstance(flags, int) or not (0 <= flags <= _MAX_FLAG):
-        raise PyCMSError(f"flags must be an integer between 0 and {_MAX_FLAG}")
+        msg = f"flags must be an integer between 0 and {_MAX_FLAG}"
+        raise PyCMSError(msg)
 
     try:
         if not isinstance(inputProfile, ImageCmsProfile):
@@ -489,10 +494,12 @@ def buildTransform(
     """
 
     if not isinstance(renderingIntent, int) or not (0 <= renderingIntent <= 3):
-        raise PyCMSError("renderingIntent must be an integer between 0 and 3")
+        msg = "renderingIntent must be an integer between 0 and 3"
+        raise PyCMSError(msg)
 
     if not isinstance(flags, int) or not (0 <= flags <= _MAX_FLAG):
-        raise PyCMSError("flags must be an integer between 0 and %s" + _MAX_FLAG)
+        msg = "flags must be an integer between 0 and %s" + _MAX_FLAG
+        raise PyCMSError(msg)
 
     try:
         if not isinstance(inputProfile, ImageCmsProfile):
@@ -591,10 +598,12 @@ def buildProofTransform(
     """
 
     if not isinstance(renderingIntent, int) or not (0 <= renderingIntent <= 3):
-        raise PyCMSError("renderingIntent must be an integer between 0 and 3")
+        msg = "renderingIntent must be an integer between 0 and 3"
+        raise PyCMSError(msg)
 
     if not isinstance(flags, int) or not (0 <= flags <= _MAX_FLAG):
-        raise PyCMSError("flags must be an integer between 0 and %s" + _MAX_FLAG)
+        msg = "flags must be an integer between 0 and %s" + _MAX_FLAG
+        raise PyCMSError(msg)
 
     try:
         if not isinstance(inputProfile, ImageCmsProfile):
@@ -705,17 +714,17 @@ def createProfile(colorSpace, colorTemp=-1):
     """
 
     if colorSpace not in ["LAB", "XYZ", "sRGB"]:
-        raise PyCMSError(
+        msg = (
             f"Color space not supported for on-the-fly profile creation ({colorSpace})"
         )
+        raise PyCMSError(msg)
 
     if colorSpace == "LAB":
         try:
             colorTemp = float(colorTemp)
         except (TypeError, ValueError) as e:
-            raise PyCMSError(
-                f'Color temperature must be numeric, "{colorTemp}" not valid'
-            ) from e
+            msg = f'Color temperature must be numeric, "{colorTemp}" not valid'
+            raise PyCMSError(msg) from e
 
     try:
         return core.createProfile(colorSpace, colorTemp)

src/PIL/ImageColor.py

@@ -33,7 +33,8 @@ def getrgb(color):
     :return: ``(red, green, blue[, alpha])``
     """
     if len(color) > 100:
-        raise ValueError("color specifier is too long")
+        msg = "color specifier is too long"
+        raise ValueError(msg)
     color = color.lower()
 
     rgb = colormap.get(color, None)
@@ -115,7 +116,8 @@ def getrgb(color):
     m = re.match(r"rgba\(\s*(\d+)\s*,\s*(\d+)\s*,\s*(\d+)\s*,\s*(\d+)\s*\)$", color)
     if m:
         return int(m.group(1)), int(m.group(2)), int(m.group(3)), int(m.group(4))
-    raise ValueError(f"unknown color specifier: {repr(color)}")
+    msg = f"unknown color specifier: {repr(color)}"
+    raise ValueError(msg)
 
 
 def getcolor(color, mode):

src/PIL/ImageDraw.py

@@ -69,7 +69,8 @@ class ImageDraw:
             if mode == "RGBA" and im.mode == "RGB":
                 blend = 1
             else:
-                raise ValueError("mode mismatch")
+                msg = "mode mismatch"
+                raise ValueError(msg)
         if mode == "P":
             self.palette = im.palette
         else:
@@ -437,7 +438,8 @@ class ImageDraw:
             )
 
         if embedded_color and self.mode not in ("RGB", "RGBA"):
-            raise ValueError("Embedded color supported only in RGB and RGBA modes")
+            msg = "Embedded color supported only in RGB and RGBA modes"
+            raise ValueError(msg)
 
         if font is None:
             font = self.getfont()
@@ -534,14 +536,17 @@ class ImageDraw:
         embedded_color=False,
     ):
         if direction == "ttb":
-            raise ValueError("ttb direction is unsupported for multiline text")
+            msg = "ttb direction is unsupported for multiline text"
+            raise ValueError(msg)
 
         if anchor is None:
             anchor = "la"
         elif len(anchor) != 2:
-            raise ValueError("anchor must be a 2 character string")
+            msg = "anchor must be a 2 character string"
+            raise ValueError(msg)
         elif anchor[1] in "tb":
-            raise ValueError("anchor not supported for multiline text")
+            msg = "anchor not supported for multiline text"
+            raise ValueError(msg)
 
         widths = []
         max_width = 0
@@ -578,7 +583,8 @@ class ImageDraw:
             elif align == "right":
                 left += width_difference
             else:
-                raise ValueError('align must be "left", "center" or "right"')
+                msg = 'align must be "left", "center" or "right"'
+                raise ValueError(msg)
 
             self.text(
                 (left, top),
@@ -672,9 +678,11 @@ class ImageDraw:
     ):
         """Get the length of a given string, in pixels with 1/64 precision."""
         if self._multiline_check(text):
-            raise ValueError("can't measure length of multiline text")
+            msg = "can't measure length of multiline text"
+            raise ValueError(msg)
         if embedded_color and self.mode not in ("RGB", "RGBA"):
-            raise ValueError("Embedded color supported only in RGB and RGBA modes")
+            msg = "Embedded color supported only in RGB and RGBA modes"
+            raise ValueError(msg)
 
         if font is None:
             font = self.getfont()
@@ -712,7 +720,8 @@ class ImageDraw:
     ):
         """Get the bounding box of a given string, in pixels."""
         if embedded_color and self.mode not in ("RGB", "RGBA"):
-            raise ValueError("Embedded color supported only in RGB and RGBA modes")
+            msg = "Embedded color supported only in RGB and RGBA modes"
+            raise ValueError(msg)
 
         if self._multiline_check(text):
             return self.multiline_textbbox(
@@ -752,14 +761,17 @@ class ImageDraw:
         embedded_color=False,
     ):
         if direction == "ttb":
-            raise ValueError("ttb direction is unsupported for multiline text")
+            msg = "ttb direction is unsupported for multiline text"
+            raise ValueError(msg)
 
         if anchor is None:
             anchor = "la"
         elif len(anchor) != 2:
-            raise ValueError("anchor must be a 2 character string")
+            msg = "anchor must be a 2 character string"
+            raise ValueError(msg)
         elif anchor[1] in "tb":
-            raise ValueError("anchor not supported for multiline text")
+            msg = "anchor not supported for multiline text"
+            raise ValueError(msg)
 
         widths = []
         max_width = 0
@@ -803,7 +815,8 @@ class ImageDraw:
             elif align == "right":
                 left += width_difference
             else:
-                raise ValueError('align must be "left", "center" or "right"')
+                msg = 'align must be "left", "center" or "right"'
+                raise ValueError(msg)
 
             bbox_line = self.textbbox(
                 (left, top),
@@ -979,38 +992,44 @@ def _compute_regular_polygon_vertices(bounding_circle, n_sides, rotation):
     # 1. Error Handling
     # 1.1 Check `n_sides` has an appropriate value
     if not isinstance(n_sides, int):
-        raise TypeError("n_sides should be an int")
+        msg = "n_sides should be an int"
+        raise TypeError(msg)
     if n_sides < 3:
-        raise ValueError("n_sides should be an int > 2")
+        msg = "n_sides should be an int > 2"
+        raise ValueError(msg)
 
     # 1.2 Check `bounding_circle` has an appropriate value
     if not isinstance(bounding_circle, (list, tuple)):
-        raise TypeError("bounding_circle should be a tuple")
+        msg = "bounding_circle should be a tuple"
+        raise TypeError(msg)
 
     if len(bounding_circle) == 3:
         *centroid, polygon_radius = bounding_circle
     elif len(bounding_circle) == 2:
         centroid, polygon_radius = bounding_circle
     else:
-        raise ValueError(
+        msg = (
             "bounding_circle should contain 2D coordinates "
             "and a radius (e.g. (x, y, r) or ((x, y), r) )"
         )
+        raise ValueError(msg)
 
     if not all(isinstance(i, (int, float)) for i in (*centroid, polygon_radius)):
-        raise ValueError("bounding_circle should only contain numeric data")
+        msg = "bounding_circle should only contain numeric data"
+        raise ValueError(msg)
 
     if not len(centroid) == 2:
-        raise ValueError(
-            "bounding_circle centre should contain 2D coordinates (e.g. (x, y))"
-        )
+        msg = "bounding_circle centre should contain 2D coordinates (e.g. (x, y))"
+        raise ValueError(msg)
 
     if polygon_radius <= 0:
-        raise ValueError("bounding_circle radius should be > 0")
+        msg = "bounding_circle radius should be > 0"
+        raise ValueError(msg)
 
     # 1.3 Check `rotation` has an appropriate value
     if not isinstance(rotation, (int, float)):
-        raise ValueError("rotation should be an int or float")
+        msg = "rotation should be an int or float"
+        raise ValueError(msg)
 
     # 2. Define Helper Functions
     def _apply_rotation(point, degrees, centroid):

src/PIL/ImageFile.py

@@ -63,12 +63,13 @@ Dict of known error codes returned from :meth:`.PyDecoder.decode`,
 
 def raise_oserror(error):
     try:
-        message = Image.core.getcodecstatus(error)
+        msg = Image.core.getcodecstatus(error)
     except AttributeError:
-        message = ERRORS.get(error)
-    if not message:
-        message = f"decoder error {error}"
-    raise OSError(message + " when reading image file")
+        msg = ERRORS.get(error)
+    if not msg:
+        msg = f"decoder error {error}"
+    msg += " when reading image file"
+    raise OSError(msg)
 
 
 def _tilesort(t):
@@ -124,7 +125,8 @@ class ImageFile(Image.Image):
                 raise SyntaxError(v) from v
 
             if not self.mode or self.size[0] <= 0 or self.size[1] <= 0:
-                raise SyntaxError("not identified by this driver")
+                msg = "not identified by this driver"
+                raise SyntaxError(msg)
         except BaseException:
             # close the file only if we have opened it this constructor
             if self._exclusive_fp:
@@ -154,7 +156,8 @@ class ImageFile(Image.Image):
         """Load image data based on tile list"""
 
         if self.tile is None:
-            raise OSError("cannot load this image")
+            msg = "cannot load this image"
+            raise OSError(msg)
 
         pixel = Image.Image.load(self)
         if not self.tile:
@@ -249,16 +252,18 @@ class ImageFile(Image.Image):
                                 if LOAD_TRUNCATED_IMAGES:
                                     break
                                 else:
-                                    raise OSError("image file is truncated") from e
+                                    msg = "image file is truncated"
+                                    raise OSError(msg) from e
 
                             if not s:  # truncated jpeg
                                 if LOAD_TRUNCATED_IMAGES:
                                     break
                                 else:
-                                    raise OSError(
+                                    msg = (
                                         "image file is truncated "
                                         f"({len(b)} bytes not processed)"
                                     )
+                                    raise OSError(msg)
 
                             b = b + s
                             n, err_code = decoder.decode(b)
@@ -314,7 +319,8 @@ class ImageFile(Image.Image):
                 and frame >= self.n_frames + self._min_frame
             )
         ):
-            raise EOFError("attempt to seek outside sequence")
+            msg = "attempt to seek outside sequence"
+            raise EOFError(msg)
 
         return self.tell() != frame
 
@@ -328,12 +334,14 @@ class StubImageFile(ImageFile):
     """
 
     def _open(self):
-        raise NotImplementedError("StubImageFile subclass must implement _open")
+        msg = "StubImageFile subclass must implement _open"
+        raise NotImplementedError(msg)
 
     def load(self):
         loader = self._load()
         if loader is None:
-            raise OSError(f"cannot find loader for this {self.format} file")
+            msg = f"cannot find loader for this {self.format} file"
+            raise OSError(msg)
         image = loader.load(self)
         assert image is not None
         # become the other object (!)
@@ -343,7 +351,8 @@ class StubImageFile(ImageFile):
 
     def _load(self):
         """(Hook) Find actual image loader."""
-        raise NotImplementedError("StubImageFile subclass must implement _load")
+        msg = "StubImageFile subclass must implement _load"
+        raise NotImplementedError(msg)
 
 
 class Parser:
@@ -468,9 +477,11 @@ class Parser:
             self.feed(b"")
             self.data = self.decoder = None
             if not self.finished:
-                raise OSError("image was incomplete")
+                msg = "image was incomplete"
+                raise OSError(msg)
         if not self.image:
-            raise OSError("cannot parse this image")
+            msg = "cannot parse this image"
+            raise OSError(msg)
         if self.data:
             # incremental parsing not possible; reopen the file
             # not that we have all data
@@ -535,7 +546,8 @@ def _encode_tile(im, fp, tile, bufsize, fh, exc=None):
                     # slight speedup: compress to real file object
                     s = encoder.encode_to_file(fh, bufsize)
             if s < 0:
-                raise OSError(f"encoder error {s} when writing image file") from exc
+                msg = f"encoder error {s} when writing image file"
+                raise OSError(msg) from exc
         finally:
             encoder.cleanup()
 
@@ -558,7 +570,8 @@ def _safe_read(fp, size):
     if size <= SAFEBLOCK:
         data = fp.read(size)
         if len(data) < size:
-            raise OSError("Truncated File Read")
+            msg = "Truncated File Read"
+            raise OSError(msg)
         return data
     data = []
     remaining_size = size
@@ -569,7 +582,8 @@ def _safe_read(fp, size):
         data.append(block)
         remaining_size -= len(block)
     if sum(len(d) for d in data) < size:
-        raise OSError("Truncated File Read")
+        msg = "Truncated File Read"
+        raise OSError(msg)
     return b"".join(data)
 
 
@@ -645,13 +659,15 @@ class PyCodec:
             self.state.ysize = y1 - y0
 
         if self.state.xsize <= 0 or self.state.ysize <= 0:
-            raise ValueError("Size cannot be negative")
+            msg = "Size cannot be negative"
+            raise ValueError(msg)
 
         if (
             self.state.xsize + self.state.xoff > self.im.size[0]
             or self.state.ysize + self.state.yoff > self.im.size[1]
         ):
-            raise ValueError("Tile cannot extend outside image")
+            msg = "Tile cannot extend outside image"
+            raise ValueError(msg)
 
 
 class PyDecoder(PyCodec):
@@ -696,9 +712,11 @@ class PyDecoder(PyCodec):
         s = d.decode(data)
 
         if s[0] >= 0:
-            raise ValueError("not enough image data")
+            msg = "not enough image data"
+            raise ValueError(msg)
         if s[1] != 0:
-            raise ValueError("cannot decode image data")
+            msg = "cannot decode image data"
+            raise ValueError(msg)
 
 
 class PyEncoder(PyCodec):

src/PIL/ImageFilter.py

@@ -28,7 +28,8 @@ class MultibandFilter(Filter):
 class BuiltinFilter(MultibandFilter):
     def filter(self, image):
         if image.mode == "P":
-            raise ValueError("cannot filter palette images")
+            msg = "cannot filter palette images"
+            raise ValueError(msg)
         return image.filter(*self.filterargs)
 
 
@@ -57,7 +58,8 @@ class Kernel(BuiltinFilter):
             # default scale is sum of kernel
             scale = functools.reduce(lambda a, b: a + b, kernel)
         if size[0] * size[1] != len(kernel):
-            raise ValueError("not enough coefficients in kernel")
+            msg = "not enough coefficients in kernel"
+            raise ValueError(msg)
         self.filterargs = size, scale, offset, kernel
 
 
@@ -80,7 +82,8 @@ class RankFilter(Filter):
 
     def filter(self, image):
         if image.mode == "P":
-            raise ValueError("cannot filter palette images")
+            msg = "cannot filter palette images"
+            raise ValueError(msg)
         image = image.expand(self.size // 2, self.size // 2)
         return image.rankfilter(self.size, self.rank)
 
@@ -355,7 +358,8 @@ class Color3DLUT(MultibandFilter):
 
     def __init__(self, size, table, channels=3, target_mode=None, **kwargs):
         if channels not in (3, 4):
-            raise ValueError("Only 3 or 4 output channels are supported")
+            msg = "Only 3 or 4 output channels are supported"
+            raise ValueError(msg)
         self.size = size = self._check_size(size)
         self.channels = channels
         self.mode = target_mode
@@ -395,19 +399,21 @@ class Color3DLUT(MultibandFilter):
                 table, raw_table = [], table
                 for pixel in raw_table:
                     if len(pixel) != channels:
-                        raise ValueError(
+                        msg = (
                             "The elements of the table should "
-                            "have a length of {}.".format(channels)
+                            f"have a length of {channels}."
                         )
+                        raise ValueError(msg)
                     table.extend(pixel)
 
         if wrong_size or len(table) != items * channels:
-            raise ValueError(
+            msg = (
                 "The table should have either channels * size**3 float items "
                 "or size**3 items of channels-sized tuples with floats. "
                 f"Table should be: {channels}x{size[0]}x{size[1]}x{size[2]}. "
                 f"Actual length: {len(table)}"
             )
+            raise ValueError(msg)
         self.table = table
 
     @staticmethod
@@ -415,15 +421,15 @@ class Color3DLUT(MultibandFilter):
         try:
             _, _, _ = size
         except ValueError as e:
-            raise ValueError(
-                "Size should be either an integer or a tuple of three integers."
-            ) from e
+            msg = "Size should be either an integer or a tuple of three integers."
+            raise ValueError(msg) from e
         except TypeError:
             size = (size, size, size)
         size = [int(x) for x in size]
         for size_1d in size:
             if not 2 <= size_1d <= 65:
-                raise ValueError("Size should be in [2, 65] range.")
+                msg = "Size should be in [2, 65] range."
+                raise ValueError(msg)
         return size
 
     @classmethod
@@ -441,7 +447,8 @@ class Color3DLUT(MultibandFilter):
         """
         size_1d, size_2d, size_3d = cls._check_size(size)
         if channels not in (3, 4):
-            raise ValueError("Only 3 or 4 output channels are supported")
+            msg = "Only 3 or 4 output channels are supported"
+            raise ValueError(msg)
 
         table = [0] * (size_1d * size_2d * size_3d * channels)
         idx_out = 0
@@ -481,7 +488,8 @@ class Color3DLUT(MultibandFilter):
                             lookup table.
         """
         if channels not in (None, 3, 4):
-            raise ValueError("Only 3 or 4 output channels are supported")
+            msg = "Only 3 or 4 output channels are supported"
+            raise ValueError(msg)
         ch_in = self.channels
         ch_out = channels or ch_in
         size_1d, size_2d, size_3d = self.size

src/PIL/ImageFont.py

@@ -50,13 +50,15 @@ def __getattr__(name):
             if name in enum.__members__:
                 deprecate(f"{prefix}{name}", 10, f"{enum.__name__}.{name}")
                 return enum[name]
-    raise AttributeError(f"module '{__name__}' has no attribute '{name}'")
+    msg = f"module '{__name__}' has no attribute '{name}'"
+    raise AttributeError(msg)
 
 
 class _ImagingFtNotInstalled:
     # module placeholder
     def __getattr__(self, id):
-        raise ImportError("The _imagingft C module is not installed")
+        msg = "The _imagingft C module is not installed"
+        raise ImportError(msg)
 
 
 try:
@@ -105,7 +107,8 @@ class ImageFont:
             else:
                 if image:
                     image.close()
-                raise OSError("cannot find glyph data file")
+                msg = "cannot find glyph data file"
+                raise OSError(msg)
 
             self.file = fullname
 
@@ -116,7 +119,8 @@ class ImageFont:
 
         # read PILfont header
         if file.readline() != b"PILfont\n":
-            raise SyntaxError("Not a PILfont file")
+            msg = "Not a PILfont file"
+            raise SyntaxError(msg)
         file.readline().split(b";")
         self.info = []  # FIXME: should be a dictionary
         while True:
@@ -130,7 +134,8 @@ class ImageFont:
 
         # check image
         if image.mode not in ("1", "L"):
-            raise TypeError("invalid font image mode")
+            msg = "invalid font image mode"
+            raise TypeError(msg)
 
         image.load()
 
@@ -817,7 +822,8 @@ class FreeTypeFont:
         try:
             names = self.font.getvarnames()
         except AttributeError as e:
-            raise NotImplementedError("FreeType 2.9.1 or greater is required") from e
+            msg = "FreeType 2.9.1 or greater is required"
+            raise NotImplementedError(msg) from e
         return [name.replace(b"\x00", b"") for name in names]
 
     def set_variation_by_name(self, name):
@@ -847,7 +853,8 @@ class FreeTypeFont:
         try:
             axes = self.font.getvaraxes()
         except AttributeError as e:
-            raise NotImplementedError("FreeType 2.9.1 or greater is required") from e
+            msg = "FreeType 2.9.1 or greater is required"
+            raise NotImplementedError(msg) from e
         for axis in axes:
             axis["name"] = axis["name"].replace(b"\x00", b"")
         return axes
@@ -860,7 +867,8 @@ class FreeTypeFont:
         try:
             self.font.setvaraxes(axes)
         except AttributeError as e:
-            raise NotImplementedError("FreeType 2.9.1 or greater is required") from e
+            msg = "FreeType 2.9.1 or greater is required"
+            raise NotImplementedError(msg) from e
 
 
 class TransposedFont:
@@ -914,9 +922,8 @@ class TransposedFont:
 
     def getlength(self, text, *args, **kwargs):
         if self.orientation in (Image.Transpose.ROTATE_90, Image.Transpose.ROTATE_270):
-            raise ValueError(
-                "text length is undefined for text rotated by 90 or 270 degrees"
-            )
+            msg = "text length is undefined for text rotated by 90 or 270 degrees"
+            raise ValueError(msg)
         return self.font.getlength(text, *args, **kwargs)
 
 
@@ -1061,7 +1068,8 @@ def load_path(filename):
                 return load(os.path.join(directory, filename))
             except OSError:
                 pass
-    raise OSError("cannot find font file")
+    msg = "cannot find font file"
+    raise OSError(msg)
 
 
 def load_default():

src/PIL/ImageGrab.py

@@ -75,7 +75,8 @@ def grab(bbox=None, include_layered_windows=False, all_screens=False, xdisplay=N
             return im
     # use xdisplay=None for default display on non-win32/macOS systems
     if not Image.core.HAVE_XCB:
-        raise OSError("Pillow was built without XCB support")
+        msg = "Pillow was built without XCB support"
+        raise OSError(msg)
     size, data = Image.core.grabscreen_x11(xdisplay)
     im = Image.frombytes("RGB", size, data, "raw", "BGRX", size[0] * 4, 1)
     if bbox:
@@ -132,4 +133,17 @@ def grabclipboard():
                 return BmpImagePlugin.DibImageFile(data)
         return None
     else:
-        raise NotImplementedError("ImageGrab.grabclipboard() is macOS and Windows only")
+        if shutil.which("wl-paste"):
+            args = ["wl-paste"]
+        elif shutil.which("xclip"):
+            args = ["xclip", "-selection", "clipboard", "-t", "image/png", "-o"]
+        else:
+            msg = "wl-paste or xclip is required for ImageGrab.grabclipboard() on Linux"
+            raise NotImplementedError(msg)
+        fh, filepath = tempfile.mkstemp()
+        subprocess.call(args, stdout=fh)
+        os.close(fh)
+        im = Image.open(filepath)
+        im.load()
+        os.unlink(filepath)
+        return im

src/PIL/ImageMath.py

@@ -39,7 +39,8 @@ class _Operand:
             elif im1.im.mode in ("I", "F"):
                 return im1.im
             else:
-                raise ValueError(f"unsupported mode: {im1.im.mode}")
+                msg = f"unsupported mode: {im1.im.mode}"
+                raise ValueError(msg)
         else:
             # argument was a constant
             if _isconstant(im1) and self.im.mode in ("1", "L", "I"):
@@ -56,7 +57,8 @@ class _Operand:
             try:
                 op = getattr(_imagingmath, op + "_" + im1.mode)
             except AttributeError as e:
-                raise TypeError(f"bad operand type for '{op}'") from e
+                msg = f"bad operand type for '{op}'"
+                raise TypeError(msg) from e
             _imagingmath.unop(op, out.im.id, im1.im.id)
         else:
             # binary operation
@@ -80,7 +82,8 @@ class _Operand:
             try:
                 op = getattr(_imagingmath, op + "_" + im1.mode)
             except AttributeError as e:
-                raise TypeError(f"bad operand type for '{op}'") from e
+                msg = f"bad operand type for '{op}'"
+                raise TypeError(msg) from e
             _imagingmath.binop(op, out.im.id, im1.im.id, im2.im.id)
         return _Operand(out)
 
@@ -249,7 +252,8 @@ def eval(expression, _dict={}, **kw):
 
         for name in code.co_names:
             if name not in args and name != "abs":
-                raise ValueError(f"'{name}' not allowed")
+                msg = f"'{name}' not allowed"
+                raise ValueError(msg)
 
     scan(compiled_code)
     out = builtins.eval(expression, {"__builtins": {"abs": abs}}, args)

src/PIL/ImageMorph.py

@@ -81,7 +81,8 @@ class LutBuilder:
                 ],
             }
             if op_name not in known_patterns:
-                raise Exception("Unknown pattern " + op_name + "!")
+                msg = "Unknown pattern " + op_name + "!"
+                raise Exception(msg)
 
             self.patterns = known_patterns[op_name]
 
@@ -145,7 +146,8 @@ class LutBuilder:
         for p in self.patterns:
             m = re.search(r"(\w*):?\s*\((.+?)\)\s*->\s*(\d)", p.replace("\n", ""))
             if not m:
-                raise Exception('Syntax error in pattern "' + p + '"')
+                msg = 'Syntax error in pattern "' + p + '"'
+                raise Exception(msg)
             options = m.group(1)
             pattern = m.group(2)
             result = int(m.group(3))
@@ -193,10 +195,12 @@ class MorphOp:
         Returns a tuple of the number of changed pixels and the
         morphed image"""
         if self.lut is None:
-            raise Exception("No operator loaded")
+            msg = "No operator loaded"
+            raise Exception(msg)
 
         if image.mode != "L":
-            raise ValueError("Image mode must be L")
+            msg = "Image mode must be L"
+            raise ValueError(msg)
         outimage = Image.new(image.mode, image.size, None)
         count = _imagingmorph.apply(bytes(self.lut), image.im.id, outimage.im.id)
         return count, outimage
@@ -208,10 +212,12 @@ class MorphOp:
         Returns a list of tuples of (x,y) coordinates
         of all matching pixels. See :ref:`coordinate-system`."""
         if self.lut is None:
-            raise Exception("No operator loaded")
+            msg = "No operator loaded"
+            raise Exception(msg)
 
         if image.mode != "L":
-            raise ValueError("Image mode must be L")
+            msg = "Image mode must be L"
+            raise ValueError(msg)
         return _imagingmorph.match(bytes(self.lut), image.im.id)
 
     def get_on_pixels(self, image):
@@ -221,7 +227,8 @@ class MorphOp:
         of all matching pixels. See :ref:`coordinate-system`."""
 
         if image.mode != "L":
-            raise ValueError("Image mode must be L")
+            msg = "Image mode must be L"
+            raise ValueError(msg)
         return _imagingmorph.get_on_pixels(image.im.id)
 
     def load_lut(self, filename):
@@ -231,12 +238,14 @@ class MorphOp:
 
         if len(self.lut) != LUT_SIZE:
             self.lut = None
-            raise Exception("Wrong size operator file!")
+            msg = "Wrong size operator file!"
+            raise Exception(msg)
 
     def save_lut(self, filename):
         """Save an operator to an mrl file"""
         if self.lut is None:
-            raise Exception("No operator loaded")
+            msg = "No operator loaded"
+            raise Exception(msg)
         with open(filename, "wb") as f:
             f.write(self.lut)
 

src/PIL/ImageOps.py

@@ -49,13 +49,15 @@ def _color(color, mode):
 def _lut(image, lut):
     if image.mode == "P":
         # FIXME: apply to lookup table, not image data
-        raise NotImplementedError("mode P support coming soon")
+        msg = "mode P support coming soon"
+        raise NotImplementedError(msg)
     elif image.mode in ("L", "RGB"):
         if image.mode == "RGB" and len(lut) == 256:
             lut = lut + lut + lut
         return image.point(lut)
     else:
-        raise OSError("not supported for this image mode")
+        msg = "not supported for this image mode"
+        raise OSError(msg)
 
 
 #
@@ -332,7 +334,8 @@ def scale(image, factor, resample=Image.Resampling.BICUBIC):
     if factor == 1:
         return image.copy()
     elif factor <= 0:
-        raise ValueError("the factor must be greater than 0")
+        msg = "the factor must be greater than 0"
+        raise ValueError(msg)
     else:
         size = (round(factor * image.width), round(factor * image.height))
         return image.resize(size, resample)

src/PIL/ImagePalette.py

@@ -42,7 +42,8 @@ class ImagePalette:
         if size != 0:
             deprecate("The size parameter", 10, None)
             if size != len(self.palette):
-                raise ValueError("wrong palette size")
+                msg = "wrong palette size"
+                raise ValueError(msg)
 
     @property
     def palette(self):
@@ -97,7 +98,8 @@ class ImagePalette:
         .. warning:: This method is experimental.
         """
         if self.rawmode:
-            raise ValueError("palette contains raw palette data")
+            msg = "palette contains raw palette data"
+            raise ValueError(msg)
         if isinstance(self.palette, bytes):
             return self.palette
         arr = array.array("B", self.palette)
@@ -112,14 +114,14 @@ class ImagePalette:
         .. warning:: This method is experimental.
         """
         if self.rawmode:
-            raise ValueError("palette contains raw palette data")
+            msg = "palette contains raw palette data"
+            raise ValueError(msg)
         if isinstance(color, tuple):
             if self.mode == "RGB":
                 if len(color) == 4:
                     if color[3] != 255:
-                        raise ValueError(
-                            "cannot add non-opaque RGBA color to RGB palette"
-                        )
+                        msg = "cannot add non-opaque RGBA color to RGB palette"
+                        raise ValueError(msg)
                     color = color[:3]
             elif self.mode == "RGBA":
                 if len(color) == 3:
@@ -147,7 +149,8 @@ class ImagePalette:
                                 index = i
                                 break
                     if index >= 256:
-                        raise ValueError("cannot allocate more than 256 colors") from e
+                        msg = "cannot allocate more than 256 colors"
+                        raise ValueError(msg) from e
                 self.colors[color] = index
                 if index * 3 < len(self.palette):
                     self._palette = (
@@ -160,7 +163,8 @@ class ImagePalette:
                 self.dirty = 1
                 return index
         else:
-            raise ValueError(f"unknown color specifier: {repr(color)}")
+            msg = f"unknown color specifier: {repr(color)}"
+            raise ValueError(msg)
 
     def save(self, fp):
         """Save palette to text file.
@@ -168,7 +172,8 @@ class ImagePalette:
         .. warning:: This method is experimental.
         """
         if self.rawmode:
-            raise ValueError("palette contains raw palette data")
+            msg = "palette contains raw palette data"
+            raise ValueError(msg)
         if isinstance(fp, str):
             fp = open(fp, "w")
         fp.write("# Palette\n")
@@ -263,6 +268,7 @@ def load(filename):
                 # traceback.print_exc()
                 pass
         else:
-            raise OSError("cannot load palette")
+            msg = "cannot load palette"
+            raise OSError(msg)
 
     return lut  # data, rawmode

src/PIL/ImageQt.py

@@ -179,7 +179,8 @@ def _toqclass_helper(im):
     else:
         if exclusive_fp:
             im.close()
-        raise ValueError(f"unsupported image mode {repr(im.mode)}")
+        msg = f"unsupported image mode {repr(im.mode)}"
+        raise ValueError(msg)
 
     size = im.size
     __data = data or align8to32(im.tobytes(), size[0], im.mode)

src/PIL/ImageSequence.py

@@ -30,7 +30,8 @@ class Iterator:
 
     def __init__(self, im):
         if not hasattr(im, "seek"):
-            raise AttributeError("im must have seek method")
+            msg = "im must have seek method"
+            raise AttributeError(msg)
         self.im = im
         self.position = getattr(self.im, "_min_frame", 0)
 

src/PIL/ImageShow.py

@@ -124,7 +124,8 @@ class Viewer:
                 deprecate("The 'file' argument", 10, "'path'")
                 path = options.pop("file")
             else:
-                raise TypeError("Missing required argument: 'path'")
+                msg = "Missing required argument: 'path'"
+                raise TypeError(msg)
         os.system(self.get_command(path, **options))  # nosec
         return 1
 
@@ -176,7 +177,8 @@ class MacViewer(Viewer):
                 deprecate("The 'file' argument", 10, "'path'")
                 path = options.pop("file")
             else:
-                raise TypeError("Missing required argument: 'path'")
+                msg = "Missing required argument: 'path'"
+                raise TypeError(msg)
         subprocess.call(["open", "-a", "Preview.app", path])
         executable = sys.executable or shutil.which("python3")
         if executable:
@@ -226,7 +228,8 @@ class XDGViewer(UnixViewer):
                 deprecate("The 'file' argument", 10, "'path'")
                 path = options.pop("file")
             else:
-                raise TypeError("Missing required argument: 'path'")
+                msg = "Missing required argument: 'path'"
+                raise TypeError(msg)
         subprocess.Popen(["xdg-open", path])
         return 1
 
@@ -255,7 +258,8 @@ class DisplayViewer(UnixViewer):
                 deprecate("The 'file' argument", 10, "'path'")
                 path = options.pop("file")
             else:
-                raise TypeError("Missing required argument: 'path'")
+                msg = "Missing required argument: 'path'"
+                raise TypeError(msg)
         args = ["display"]
         title = options.get("title")
         if title:
@@ -286,7 +290,8 @@ class GmDisplayViewer(UnixViewer):
                 deprecate("The 'file' argument", 10, "'path'")
                 path = options.pop("file")
             else:
-                raise TypeError("Missing required argument: 'path'")
+                msg = "Missing required argument: 'path'"
+                raise TypeError(msg)
         subprocess.Popen(["gm", "display", path])
         return 1
 
@@ -311,7 +316,8 @@ class EogViewer(UnixViewer):
                 deprecate("The 'file' argument", 10, "'path'")
                 path = options.pop("file")
             else:
-                raise TypeError("Missing required argument: 'path'")
+                msg = "Missing required argument: 'path'"
+                raise TypeError(msg)
         subprocess.Popen(["eog", "-n", path])
         return 1
 
@@ -342,7 +348,8 @@ class XVViewer(UnixViewer):
                 deprecate("The 'file' argument", 10, "'path'")
                 path = options.pop("file")
             else:
-                raise TypeError("Missing required argument: 'path'")
+                msg = "Missing required argument: 'path'"
+                raise TypeError(msg)
         args = ["xv"]
         title = options.get("title")
         if title:

src/PIL/ImageStat.py

@@ -36,7 +36,8 @@ class Stat:
         except AttributeError:
             self.h = image_or_list  # assume it to be a histogram list
         if not isinstance(self.h, list):
-            raise TypeError("first argument must be image or list")
+            msg = "first argument must be image or list"
+            raise TypeError(msg)
         self.bands = list(range(len(self.h) // 256))
 
     def __getattr__(self, id):

src/PIL/ImageTk.py

@@ -284,7 +284,8 @@ def _show(image, title):
             super().__init__(master, image=self.image, bg="black", bd=0)
 
     if not tkinter._default_root:
-        raise OSError("tkinter not initialized")
+        msg = "tkinter not initialized"
+        raise OSError(msg)
     top = tkinter.Toplevel()
     if title:
         top.title(title)

src/PIL/ImtImagePlugin.py

@@ -41,7 +41,8 @@ class ImtImageFile(ImageFile.ImageFile):
 
         buffer = self.fp.read(100)
         if b"\n" not in buffer:
-            raise SyntaxError("not an IM file")
+            msg = "not an IM file"
+            raise SyntaxError(msg)
 
         xsize = ysize = 0
 

src/PIL/IptcImagePlugin.py

@@ -66,12 +66,14 @@ class IptcImageFile(ImageFile.ImageFile):
 
         # syntax
         if s[0] != 0x1C or tag[0] < 1 or tag[0] > 9:
-            raise SyntaxError("invalid IPTC/NAA file")
+            msg = "invalid IPTC/NAA file"
+            raise SyntaxError(msg)
 
         # field size
         size = s[3]
         if size > 132:
-            raise OSError("illegal field length in IPTC/NAA file")
+            msg = "illegal field length in IPTC/NAA file"
+            raise OSError(msg)
         elif size == 128:
             size = 0
         elif size > 128:
@@ -122,7 +124,8 @@ class IptcImageFile(ImageFile.ImageFile):
         try:
             compression = COMPRESSION[self.getint((3, 120))]
         except KeyError as e:
-            raise OSError("Unknown IPTC image compression") from e
+            msg = "Unknown IPTC image compression"
+            raise OSError(msg) from e
 
         # tile
         if tag == (8, 10):

src/PIL/Jpeg2KImagePlugin.py

@@ -44,13 +44,13 @@ class BoxReader:
 
     def _read_bytes(self, num_bytes):
         if not self._can_read(num_bytes):
-            raise SyntaxError("Not enough data in header")
+            msg = "Not enough data in header"
+            raise SyntaxError(msg)
 
         data = self.fp.read(num_bytes)
         if len(data) < num_bytes:
-            raise OSError(
-                f"Expected to read {num_bytes} bytes but only got {len(data)}."
-            )
+            msg = f"Expected to read {num_bytes} bytes but only got {len(data)}."
+            raise OSError(msg)
 
         if self.remaining_in_box > 0:
             self.remaining_in_box -= num_bytes
@@ -87,7 +87,8 @@ class BoxReader:
             hlen = 8
 
         if lbox < hlen or not self._can_read(lbox - hlen):
-            raise SyntaxError("Invalid header length")
+            msg = "Invalid header length"
+            raise SyntaxError(msg)
 
         self.remaining_in_box = lbox - hlen
         return tbox
@@ -189,7 +190,8 @@ def _parse_jp2_header(fp):
                     break
 
     if size is None or mode is None:
-        raise SyntaxError("Malformed JP2 header")
+        msg = "Malformed JP2 header"
+        raise SyntaxError(msg)
 
     return size, mode, mimetype, dpi
 
@@ -217,10 +219,12 @@ class Jpeg2KImageFile(ImageFile.ImageFile):
                 if dpi is not None:
                     self.info["dpi"] = dpi
             else:
-                raise SyntaxError("not a JPEG 2000 file")
+                msg = "not a JPEG 2000 file"
+                raise SyntaxError(msg)
 
         if self.size is None or self.mode is None:
-            raise SyntaxError("unable to determine size/mode")
+            msg = "unable to determine size/mode"
+            raise SyntaxError(msg)
 
         self._reduce = 0
         self.layers = 0
@@ -312,7 +316,8 @@ def _save(im, fp, filename):
             ]
         )
     ):
-        raise ValueError("quality_layers must be a sequence of numbers")
+        msg = "quality_layers must be a sequence of numbers"
+        raise ValueError(msg)
 
     num_resolutions = info.get("num_resolutions", 0)
     cblk_size = info.get("codeblock_size", None)
@@ -321,6 +326,7 @@ def _save(im, fp, filename):
     progression = info.get("progression", "LRCP")
     cinema_mode = info.get("cinema_mode", "no")
     mct = info.get("mct", 0)
+    signed = info.get("signed", False)
     fd = -1
 
     if hasattr(fp, "fileno"):
@@ -342,6 +348,7 @@ def _save(im, fp, filename):
         progression,
         cinema_mode,
         mct,
+        signed,
         fd,
     )
 

src/PIL/JpegImagePlugin.py

@@ -204,7 +204,8 @@ def SOF(self, marker):
 
     self.bits = s[0]
     if self.bits != 8:
-        raise SyntaxError(f"cannot handle {self.bits}-bit layers")
+        msg = f"cannot handle {self.bits}-bit layers"
+        raise SyntaxError(msg)
 
     self.layers = s[5]
     if self.layers == 1:
@@ -214,7 +215,8 @@ def SOF(self, marker):
     elif self.layers == 4:
         self.mode = "CMYK"
     else:
-        raise SyntaxError(f"cannot handle {self.layers}-layer images")
+        msg = f"cannot handle {self.layers}-layer images"
+        raise SyntaxError(msg)
 
     if marker in [0xFFC2, 0xFFC6, 0xFFCA, 0xFFCE]:
         self.info["progressive"] = self.info["progression"] = 1
@@ -253,7 +255,8 @@ def DQT(self, marker):
         precision = 1 if (v // 16 == 0) else 2  # in bytes
         qt_length = 1 + precision * 64
         if len(s) < qt_length:
-            raise SyntaxError("bad quantization table marker")
+            msg = "bad quantization table marker"
+            raise SyntaxError(msg)
         data = array.array("B" if precision == 1 else "H", s[1:qt_length])
         if sys.byteorder == "little" and precision > 1:
             data.byteswap()  # the values are always big-endian
@@ -350,7 +353,8 @@ class JpegImageFile(ImageFile.ImageFile):
         s = self.fp.read(3)
 
         if not _accept(s):
-            raise SyntaxError("not a JPEG file")
+            msg = "not a JPEG file"
+            raise SyntaxError(msg)
         s = b"\xFF"
 
         # Create attributes
@@ -394,7 +398,8 @@ class JpegImageFile(ImageFile.ImageFile):
             elif i == 0xFF00:  # Skip extraneous data (escaped 0xFF)
                 s = self.fp.read(1)
             else:
-                raise SyntaxError("no marker found")
+                msg = "no marker found"
+                raise SyntaxError(msg)
 
     def load_read(self, read_bytes):
         """
@@ -458,7 +463,8 @@ class JpegImageFile(ImageFile.ImageFile):
         if os.path.exists(self.filename):
             subprocess.check_call(["djpeg", "-outfile", path, self.filename])
         else:
-            raise ValueError("Invalid Filename")
+            msg = "Invalid Filename"
+            raise ValueError(msg)
 
         try:
             with Image.open(path) as _im:
@@ -524,12 +530,14 @@ def _getmp(self):
         info.load(file_contents)
         mp = dict(info)
     except Exception as e:
-        raise SyntaxError("malformed MP Index (unreadable directory)") from e
+        msg = "malformed MP Index (unreadable directory)"
+        raise SyntaxError(msg) from e
     # it's an error not to have a number of images
     try:
         quant = mp[0xB001]
     except KeyError as e:
-        raise SyntaxError("malformed MP Index (no number of images)") from e
+        msg = "malformed MP Index (no number of images)"
+        raise SyntaxError(msg) from e
     # get MP entries
     mpentries = []
     try:
@@ -551,7 +559,8 @@ def _getmp(self):
             if mpentryattr["ImageDataFormat"] == 0:
                 mpentryattr["ImageDataFormat"] = "JPEG"
             else:
-                raise SyntaxError("unsupported picture format in MPO")
+                msg = "unsupported picture format in MPO"
+                raise SyntaxError(msg)
             mptypemap = {
                 0x000000: "Undefined",
                 0x010001: "Large Thumbnail (VGA Equivalent)",
@@ -566,7 +575,8 @@ def _getmp(self):
             mpentries.append(mpentry)
         mp[0xB002] = mpentries
     except KeyError as e:
-        raise SyntaxError("malformed MP Index (bad MP Entry)") from e
+        msg = "malformed MP Index (bad MP Entry)"
+        raise SyntaxError(msg) from e
     # Next we should try and parse the individual image unique ID list;
     # we don't because I've never seen this actually used in a real MPO
     # file and so can't test it.
@@ -626,12 +636,14 @@ def get_sampling(im):
 
 def _save(im, fp, filename):
     if im.width == 0 or im.height == 0:
-        raise ValueError("cannot write empty image as JPEG")
+        msg = "cannot write empty image as JPEG"
+        raise ValueError(msg)
 
     try:
         rawmode = RAWMODE[im.mode]
     except KeyError as e:
-        raise OSError(f"cannot write mode {im.mode} as JPEG") from e
+        msg = f"cannot write mode {im.mode} as JPEG"
+        raise OSError(msg) from e
 
     info = im.encoderinfo
 
@@ -651,7 +663,8 @@ def _save(im, fp, filename):
         subsampling = preset.get("subsampling", -1)
         qtables = preset.get("quantization")
     elif not isinstance(quality, int):
-        raise ValueError("Invalid quality setting")
+        msg = "Invalid quality setting"
+        raise ValueError(msg)
     else:
         if subsampling in presets:
             subsampling = presets[subsampling].get("subsampling", -1)
@@ -670,7 +683,8 @@ def _save(im, fp, filename):
         subsampling = 2
     elif subsampling == "keep":
         if im.format != "JPEG":
-            raise ValueError("Cannot use 'keep' when original image is not a JPEG")
+            msg = "Cannot use 'keep' when original image is not a JPEG"
+            raise ValueError(msg)
         subsampling = get_sampling(im)
 
     def validate_qtables(qtables):
@@ -684,7 +698,8 @@ def _save(im, fp, filename):
                     for num in line.split("#", 1)[0].split()
                 ]
             except ValueError as e:
-                raise ValueError("Invalid quantization table") from e
+                msg = "Invalid quantization table"
+                raise ValueError(msg) from e
             else:
                 qtables = [lines[s : s + 64] for s in range(0, len(lines), 64)]
         if isinstance(qtables, (tuple, list, dict)):
@@ -695,21 +710,24 @@ def _save(im, fp, filename):
             elif isinstance(qtables, tuple):
                 qtables = list(qtables)
             if not (0 < len(qtables) < 5):
-                raise ValueError("None or too many quantization tables")
+                msg = "None or too many quantization tables"
+                raise ValueError(msg)
             for idx, table in enumerate(qtables):
                 try:
                     if len(table) != 64:
                         raise TypeError
                     table = array.array("H", table)
                 except TypeError as e:
-                    raise ValueError("Invalid quantization table") from e
+                    msg = "Invalid quantization table"
+                    raise ValueError(msg) from e
                 else:
                     qtables[idx] = list(table)
             return qtables
 
     if qtables == "keep":
         if im.format != "JPEG":
-            raise ValueError("Cannot use 'keep' when original image is not a JPEG")
+            msg = "Cannot use 'keep' when original image is not a JPEG"
+            raise ValueError(msg)
         qtables = getattr(im, "quantization", None)
     qtables = validate_qtables(qtables)
 

src/PIL/McIdasImagePlugin.py

@@ -39,7 +39,8 @@ class McIdasImageFile(ImageFile.ImageFile):
         # parse area file directory
         s = self.fp.read(256)
         if not _accept(s) or len(s) != 256:
-            raise SyntaxError("not an McIdas area file")
+            msg = "not an McIdas area file"
+            raise SyntaxError(msg)
 
         self.area_descriptor_raw = s
         self.area_descriptor = w = [0] + list(struct.unpack("!64i", s))
@@ -56,7 +57,8 @@ class McIdasImageFile(ImageFile.ImageFile):
             mode = "I"
             rawmode = "I;32B"
         else:
-            raise SyntaxError("unsupported McIdas format")
+            msg = "unsupported McIdas format"
+            raise SyntaxError(msg)
 
         self.mode = mode
         self._size = w[10], w[9]

src/PIL/MicImagePlugin.py

@@ -47,7 +47,8 @@ class MicImageFile(TiffImagePlugin.TiffImageFile):
         try:
             self.ole = olefile.OleFileIO(self.fp)
         except OSError as e:
-            raise SyntaxError("not an MIC file; invalid OLE file") from e
+            msg = "not an MIC file; invalid OLE file"
+            raise SyntaxError(msg) from e
 
         # find ACI subfiles with Image members (maybe not the
         # best way to identify MIC files, but what the... ;-)
@@ -60,7 +61,8 @@ class MicImageFile(TiffImagePlugin.TiffImageFile):
         # if we didn't find any images, this is probably not
         # an MIC file.
         if not self.images:
-            raise SyntaxError("not an MIC file; no image entries")
+            msg = "not an MIC file; no image entries"
+            raise SyntaxError(msg)
 
         self.frame = None
         self._n_frames = len(self.images)
@@ -77,7 +79,8 @@ class MicImageFile(TiffImagePlugin.TiffImageFile):
         try:
             filename = self.images[frame]
         except IndexError as e:
-            raise EOFError("no such frame") from e
+            msg = "no such frame"
+            raise EOFError(msg) from e
 
         self.fp = self.ole.openstream(filename)
 

src/PIL/MpegImagePlugin.py

@@ -67,7 +67,8 @@ class MpegImageFile(ImageFile.ImageFile):
         s = BitStream(self.fp)
 
         if s.read(32) != 0x1B3:
-            raise SyntaxError("not an MPEG file")
+            msg = "not an MPEG file"
+            raise SyntaxError(msg)
 
         self.mode = "RGB"
         self._size = s.read(12), s.read(12)

src/PIL/MpoImagePlugin.py

@@ -143,7 +143,8 @@ class MpoImageFile(JpegImagePlugin.JpegImageFile):
         self.fp.seek(self.offset + 2)  # skip SOI marker
         segment = self.fp.read(2)
         if not segment:
-            raise ValueError("No data found for frame")
+            msg = "No data found for frame"
+            raise ValueError(msg)
         self._size = self._initial_size
         if i16(segment) == 0xFFE1:  # APP1
             n = i16(self.fp.read(2)) - 2

src/PIL/MspImagePlugin.py

@@ -53,14 +53,16 @@ class MspImageFile(ImageFile.ImageFile):
         # Header
         s = self.fp.read(32)
         if not _accept(s):
-            raise SyntaxError("not an MSP file")
+            msg = "not an MSP file"
+            raise SyntaxError(msg)
 
         # Header checksum
         checksum = 0
         for i in range(0, 32, 2):
             checksum = checksum ^ i16(s, i)
         if checksum != 0:
-            raise SyntaxError("bad MSP checksum")
+            msg = "bad MSP checksum"
+            raise SyntaxError(msg)
 
         self.mode = "1"
         self._size = i16(s, 4), i16(s, 6)
@@ -118,7 +120,8 @@ class MspDecoder(ImageFile.PyDecoder):
                 f"<{self.state.ysize}H", self.fd.read(self.state.ysize * 2)
             )
         except struct.error as e:
-            raise OSError("Truncated MSP file in row map") from e
+            msg = "Truncated MSP file in row map"
+            raise OSError(msg) from e
 
         for x, rowlen in enumerate(rowmap):
             try:
@@ -127,9 +130,8 @@ class MspDecoder(ImageFile.PyDecoder):
                     continue
                 row = self.fd.read(rowlen)
                 if len(row) != rowlen:
-                    raise OSError(
-                        "Truncated MSP file, expected %d bytes on row %s", (rowlen, x)
-                    )
+                    msg = f"Truncated MSP file, expected {rowlen} bytes on row {x}"
+                    raise OSError(msg)
                 idx = 0
                 while idx < rowlen:
                     runtype = row[idx]
@@ -144,7 +146,8 @@ class MspDecoder(ImageFile.PyDecoder):
                         idx += runcount
 
             except struct.error as e:
-                raise OSError(f"Corrupted MSP file in row {x}") from e
+                msg = f"Corrupted MSP file in row {x}"
+                raise OSError(msg) from e
 
         self.set_as_raw(img.getvalue(), ("1", 0, 1))
 
@@ -161,7 +164,8 @@ Image.register_decoder("MSP", MspDecoder)
 def _save(im, fp, filename):
 
     if im.mode != "1":
-        raise OSError(f"cannot write mode {im.mode} as MSP")
+        msg = f"cannot write mode {im.mode} as MSP"
+        raise OSError(msg)
 
     # create MSP header
     header = [0] * 16

src/PIL/PaletteFile.py

@@ -34,7 +34,8 @@ class PaletteFile:
             if s[:1] == b"#":
                 continue
             if len(s) > 100:
-                raise SyntaxError("bad palette file")
+                msg = "bad palette file"
+                raise SyntaxError(msg)
 
             v = [int(x) for x in s.split()]
             try:

src/PIL/PalmImagePlugin.py

@@ -138,7 +138,8 @@ def _save(im, fp, filename):
             bpp = im.info["bpp"]
             im = im.point(lambda x, maxval=(1 << bpp) - 1: maxval - (x & maxval))
         else:
-            raise OSError(f"cannot write mode {im.mode} as Palm")
+            msg = f"cannot write mode {im.mode} as Palm"
+            raise OSError(msg)
 
         # we ignore the palette here
         im.mode = "P"
@@ -154,7 +155,8 @@ def _save(im, fp, filename):
 
     else:
 
-        raise OSError(f"cannot write mode {im.mode} as Palm")
+        msg = f"cannot write mode {im.mode} as Palm"
+        raise OSError(msg)
 
     #
     # make sure image data is available

src/PIL/PcdImagePlugin.py

@@ -35,7 +35,8 @@ class PcdImageFile(ImageFile.ImageFile):
         s = self.fp.read(2048)
 
         if s[:4] != b"PCD_":
-            raise SyntaxError("not a PCD file")
+            msg = "not a PCD file"
+            raise SyntaxError(msg)
 
         orientation = s[1538] & 3
         self.tile_post_rotate = None

src/PIL/PcfFontFile.py

@@ -63,7 +63,8 @@ class PcfFontFile(FontFile.FontFile):
 
         magic = l32(fp.read(4))
         if magic != PCF_MAGIC:
-            raise SyntaxError("not a PCF file")
+            msg = "not a PCF file"
+            raise SyntaxError(msg)
 
         super().__init__()
 
@@ -186,7 +187,8 @@ class PcfFontFile(FontFile.FontFile):
         nbitmaps = i32(fp.read(4))
 
         if nbitmaps != len(metrics):
-            raise OSError("Wrong number of bitmaps")
+            msg = "Wrong number of bitmaps"
+            raise OSError(msg)
 
         offsets = []
         for i in range(nbitmaps):

src/PIL/PcxImagePlugin.py

@@ -54,12 +54,14 @@ class PcxImageFile(ImageFile.ImageFile):
         # header
         s = self.fp.read(128)
         if not _accept(s):
-            raise SyntaxError("not a PCX file")
+            msg = "not a PCX file"
+            raise SyntaxError(msg)
 
         # image
         bbox = i16(s, 4), i16(s, 6), i16(s, 8) + 1, i16(s, 10) + 1
         if bbox[2] <= bbox[0] or bbox[3] <= bbox[1]:
-            raise SyntaxError("bad PCX image size")
+            msg = "bad PCX image size"
+            raise SyntaxError(msg)
         logger.debug("BBox: %s %s %s %s", *bbox)
 
         # format
@@ -105,7 +107,8 @@ class PcxImageFile(ImageFile.ImageFile):
             rawmode = "RGB;L"
 
         else:
-            raise OSError("unknown PCX mode")
+            msg = "unknown PCX mode"
+            raise OSError(msg)
 
         self.mode = mode
         self._size = bbox[2] - bbox[0], bbox[3] - bbox[1]
@@ -144,7 +147,8 @@ def _save(im, fp, filename):
     try:
         version, bits, planes, rawmode = SAVE[im.mode]
     except KeyError as e:
-        raise ValueError(f"Cannot save {im.mode} images as PCX") from e
+        msg = f"Cannot save {im.mode} images as PCX"
+        raise ValueError(msg) from e
 
     # bytes per plane
     stride = (im.size[0] * bits + 7) // 8

src/PIL/PdfImagePlugin.py

@@ -174,7 +174,8 @@ def _save(im, fp, filename, save_all=False):
                 procset = "ImageC"  # color images
                 decode = [1, 0, 1, 0, 1, 0, 1, 0]
             else:
-                raise ValueError(f"cannot save mode {im.mode}")
+                msg = f"cannot save mode {im.mode}"
+                raise ValueError(msg)
 
             #
             # image
@@ -198,7 +199,8 @@ def _save(im, fp, filename, save_all=False):
             elif filter == "RunLengthDecode":
                 ImageFile._save(im, op, [("packbits", (0, 0) + im.size, 0, im.mode)])
             else:
-                raise ValueError(f"unsupported PDF filter ({filter})")
+                msg = f"unsupported PDF filter ({filter})"
+                raise ValueError(msg)
 
             stream = op.getvalue()
             if filter == "CCITTFaxDecode":

src/PIL/PdfParser.py

@@ -138,9 +138,10 @@ class XrefTable:
         elif key in self.deleted_entries:
             generation = self.deleted_entries[key]
         else:
-            raise IndexError(
+            msg = (
                 "object ID " + str(key) + " cannot be deleted because it doesn't exist"
             )
+            raise IndexError(msg)
 
     def __contains__(self, key):
         return key in self.existing_entries or key in self.new_entries
@@ -314,9 +315,8 @@ class PdfStream:
                 expected_length = self.dictionary.Length
             return zlib.decompress(self.buf, bufsize=int(expected_length))
         else:
-            raise NotImplementedError(
-                f"stream filter {repr(self.dictionary.Filter)} unknown/unsupported"
-            )
+            msg = f"stream filter {repr(self.dictionary.Filter)} unknown/unsupported"
+            raise NotImplementedError(msg)
 
 
 def pdf_repr(x):
@@ -358,7 +358,8 @@ class PdfParser:
 
     def __init__(self, filename=None, f=None, buf=None, start_offset=0, mode="rb"):
         if buf and f:
-            raise RuntimeError("specify buf or f or filename, but not both buf and f")
+            msg = "specify buf or f or filename, but not both buf and f"
+            raise RuntimeError(msg)
         self.filename = filename
         self.buf = buf
         self.f = f
@@ -816,10 +817,10 @@ class PdfParser:
                 try:
                     stream_len = int(result[b"Length"])
                 except (TypeError, KeyError, ValueError) as e:
-                    raise PdfFormatError(
-                        "bad or missing Length in stream dict (%r)"
-                        % result.get(b"Length", None)
-                    ) from e
+                    msg = "bad or missing Length in stream dict (%r)" % result.get(
+                        b"Length", None
+                    )
+                    raise PdfFormatError(msg) from e
                 stream_data = data[m.end() : m.end() + stream_len]
                 m = cls.re_stream_end.match(data, m.end() + stream_len)
                 check_format_condition(m, "stream end not found")
@@ -873,7 +874,8 @@ class PdfParser:
         if m:
             return cls.get_literal_string(data, m.end())
         # return None, offset  # fallback (only for debugging)
-        raise PdfFormatError("unrecognized object: " + repr(data[offset : offset + 32]))
+        msg = "unrecognized object: " + repr(data[offset : offset + 32])
+        raise PdfFormatError(msg)
 
     re_lit_str_token = re.compile(
         rb"(\\[nrtbf()\\])|(\\[0-9]{1,3})|(\\(\r\n|\r|\n))|(\r\n|\r|\n)|(\()|(\))"
@@ -920,7 +922,8 @@ class PdfParser:
                 result.extend(b")")
                 nesting_depth -= 1
             offset = m.end()
-        raise PdfFormatError("unfinished literal string")
+        msg = "unfinished literal string"
+        raise PdfFormatError(msg)
 
     re_xref_section_start = re.compile(whitespace_optional + rb"xref" + newline)
     re_xref_subsection_start = re.compile(

src/PIL/PixarImagePlugin.py

@@ -44,7 +44,8 @@ class PixarImageFile(ImageFile.ImageFile):
         # assuming a 4-byte magic label
         s = self.fp.read(4)
         if not _accept(s):
-            raise SyntaxError("not a PIXAR file")
+            msg = "not a PIXAR file"
+            raise SyntaxError(msg)
 
         # read rest of header
         s = s + self.fp.read(508)

src/PIL/PngImagePlugin.py

@@ -138,14 +138,16 @@ def __getattr__(name):
             if name in enum.__members__:
                 deprecate(f"{prefix}{name}", 10, f"{enum.__name__}.{name}")
                 return enum[name]
-    raise AttributeError(f"module '{__name__}' has no attribute '{name}'")
+    msg = f"module '{__name__}' has no attribute '{name}'"
+    raise AttributeError(msg)
 
 
 def _safe_zlib_decompress(s):
     dobj = zlib.decompressobj()
     plaintext = dobj.decompress(s, MAX_TEXT_CHUNK)
     if dobj.unconsumed_tail:
-        raise ValueError("Decompressed Data Too Large")
+        msg = "Decompressed Data Too Large"
+        raise ValueError(msg)
     return plaintext
 
 
@@ -178,7 +180,8 @@ class ChunkStream:
 
         if not is_cid(cid):
             if not ImageFile.LOAD_TRUNCATED_IMAGES:
-                raise SyntaxError(f"broken PNG file (chunk {repr(cid)})")
+                msg = f"broken PNG file (chunk {repr(cid)})"
+                raise SyntaxError(msg)
 
         return cid, pos, length
 
@@ -215,13 +218,11 @@ class ChunkStream:
             crc1 = _crc32(data, _crc32(cid))
             crc2 = i32(self.fp.read(4))
             if crc1 != crc2:
-                raise SyntaxError(
-                    f"broken PNG file (bad header checksum in {repr(cid)})"
-                )
+                msg = f"broken PNG file (bad header checksum in {repr(cid)})"
+                raise SyntaxError(msg)
         except struct.error as e:
-            raise SyntaxError(
-                f"broken PNG file (incomplete checksum in {repr(cid)})"
-            ) from e
+            msg = f"broken PNG file (incomplete checksum in {repr(cid)})"
+            raise SyntaxError(msg) from e
 
     def crc_skip(self, cid, data):
         """Read checksum"""
@@ -239,7 +240,8 @@ class ChunkStream:
             try:
                 cid, pos, length = self.read()
             except struct.error as e:
-                raise OSError("truncated PNG file") from e
+                msg = "truncated PNG file"
+                raise OSError(msg) from e
 
             if cid == endchunk:
                 break
@@ -376,10 +378,11 @@ class PngStream(ChunkStream):
     def check_text_memory(self, chunklen):
         self.text_memory += chunklen
         if self.text_memory > MAX_TEXT_MEMORY:
-            raise ValueError(
+            msg = (
                 "Too much memory used in text chunks: "
                 f"{self.text_memory}>MAX_TEXT_MEMORY"
             )
+            raise ValueError(msg)
 
     def save_rewind(self):
         self.rewind_state = {
@@ -407,7 +410,8 @@ class PngStream(ChunkStream):
         logger.debug("Compression method %s", s[i])
         comp_method = s[i]
         if comp_method != 0:
-            raise SyntaxError(f"Unknown compression method {comp_method} in iCCP chunk")
+            msg = f"Unknown compression method {comp_method} in iCCP chunk"
+            raise SyntaxError(msg)
         try:
             icc_profile = _safe_zlib_decompress(s[i + 2 :])
         except ValueError:
@@ -427,7 +431,8 @@ class PngStream(ChunkStream):
         if length < 13:
             if ImageFile.LOAD_TRUNCATED_IMAGES:
                 return s
-            raise ValueError("Truncated IHDR chunk")
+            msg = "Truncated IHDR chunk"
+            raise ValueError(msg)
         self.im_size = i32(s, 0), i32(s, 4)
         try:
             self.im_mode, self.im_rawmode = _MODES[(s[8], s[9])]
@@ -436,7 +441,8 @@ class PngStream(ChunkStream):
         if s[12]:
             self.im_info["interlace"] = 1
         if s[11]:
-            raise SyntaxError("unknown filter category")
+            msg = "unknown filter category"
+            raise SyntaxError(msg)
         return s
 
     def chunk_IDAT(self, pos, length):
@@ -512,7 +518,8 @@ class PngStream(ChunkStream):
         if length < 1:
             if ImageFile.LOAD_TRUNCATED_IMAGES:
                 return s
-            raise ValueError("Truncated sRGB chunk")
+            msg = "Truncated sRGB chunk"
+            raise ValueError(msg)
         self.im_info["srgb"] = s[0]
         return s
 
@@ -523,7 +530,8 @@ class PngStream(ChunkStream):
         if length < 9:
             if ImageFile.LOAD_TRUNCATED_IMAGES:
                 return s
-            raise ValueError("Truncated pHYs chunk")
+            msg = "Truncated pHYs chunk"
+            raise ValueError(msg)
         px, py = i32(s, 0), i32(s, 4)
         unit = s[8]
         if unit == 1:  # meter
@@ -567,7 +575,8 @@ class PngStream(ChunkStream):
         else:
             comp_method = 0
         if comp_method != 0:
-            raise SyntaxError(f"Unknown compression method {comp_method} in zTXt chunk")
+            msg = f"Unknown compression method {comp_method} in zTXt chunk"
+            raise SyntaxError(msg)
         try:
             v = _safe_zlib_decompress(v[1:])
         except ValueError:
@@ -639,7 +648,8 @@ class PngStream(ChunkStream):
         if length < 8:
             if ImageFile.LOAD_TRUNCATED_IMAGES:
                 return s
-            raise ValueError("APNG contains truncated acTL chunk")
+            msg = "APNG contains truncated acTL chunk"
+            raise ValueError(msg)
         if self.im_n_frames is not None:
             self.im_n_frames = None
             warnings.warn("Invalid APNG, will use default PNG image if possible")
@@ -658,18 +668,21 @@ class PngStream(ChunkStream):
         if length < 26:
             if ImageFile.LOAD_TRUNCATED_IMAGES:
                 return s
-            raise ValueError("APNG contains truncated fcTL chunk")
+            msg = "APNG contains truncated fcTL chunk"
+            raise ValueError(msg)
         seq = i32(s)
         if (self._seq_num is None and seq != 0) or (
             self._seq_num is not None and self._seq_num != seq - 1
         ):
-            raise SyntaxError("APNG contains frame sequence errors")
+            msg = "APNG contains frame sequence errors"
+            raise SyntaxError(msg)
         self._seq_num = seq
         width, height = i32(s, 4), i32(s, 8)
         px, py = i32(s, 12), i32(s, 16)
         im_w, im_h = self.im_size
         if px + width > im_w or py + height > im_h:
-            raise SyntaxError("APNG contains invalid frames")
+            msg = "APNG contains invalid frames"
+            raise SyntaxError(msg)
         self.im_info["bbox"] = (px, py, px + width, py + height)
         delay_num, delay_den = i16(s, 20), i16(s, 22)
         if delay_den == 0:
@@ -684,11 +697,13 @@ class PngStream(ChunkStream):
             if ImageFile.LOAD_TRUNCATED_IMAGES:
                 s = ImageFile._safe_read(self.fp, length)
                 return s
-            raise ValueError("APNG contains truncated fDAT chunk")
+            msg = "APNG contains truncated fDAT chunk"
+            raise ValueError(msg)
         s = ImageFile._safe_read(self.fp, 4)
         seq = i32(s)
         if self._seq_num != seq - 1:
-            raise SyntaxError("APNG contains frame sequence errors")
+            msg = "APNG contains frame sequence errors"
+            raise SyntaxError(msg)
         self._seq_num = seq
         return self.chunk_IDAT(pos + 4, length - 4)
 
@@ -713,7 +728,8 @@ class PngImageFile(ImageFile.ImageFile):
     def _open(self):
 
         if not _accept(self.fp.read(8)):
-            raise SyntaxError("not a PNG file")
+            msg = "not a PNG file"
+            raise SyntaxError(msg)
         self._fp = self.fp
         self.__frame = 0
 
@@ -797,7 +813,8 @@ class PngImageFile(ImageFile.ImageFile):
         """Verify PNG file"""
 
         if self.fp is None:
-            raise RuntimeError("verify must be called directly after open")
+            msg = "verify must be called directly after open"
+            raise RuntimeError(msg)
 
         # back up to beginning of IDAT block
         self.fp.seek(self.tile[0][2] - 8)
@@ -821,7 +838,8 @@ class PngImageFile(ImageFile.ImageFile):
                 self._seek(f)
             except EOFError as e:
                 self.seek(last_frame)
-                raise EOFError("no more images in APNG file") from e
+                msg = "no more images in APNG file"
+                raise EOFError(msg) from e
 
     def _seek(self, frame, rewind=False):
         if frame == 0:
@@ -844,7 +862,8 @@ class PngImageFile(ImageFile.ImageFile):
             self.__frame = 0
         else:
             if frame != self.__frame + 1:
-                raise ValueError(f"cannot seek to frame {frame}")
+                msg = f"cannot seek to frame {frame}"
+                raise ValueError(msg)
 
             # ensure previous frame was loaded
             self.load()
@@ -869,11 +888,13 @@ class PngImageFile(ImageFile.ImageFile):
                     break
 
                 if cid == b"IEND":
-                    raise EOFError("No more images in APNG file")
+                    msg = "No more images in APNG file"
+                    raise EOFError(msg)
                 if cid == b"fcTL":
                     if frame_start:
                         # there must be at least one fdAT chunk between fcTL chunks
-                        raise SyntaxError("APNG missing frame data")
+                        msg = "APNG missing frame data"
+                        raise SyntaxError(msg)
                     frame_start = True
 
                 try:
@@ -1277,7 +1298,8 @@ def _save(im, fp, filename, chunk=putchunk, save_all=False):
     try:
         rawmode, mode = _OUTMODES[mode]
     except KeyError as e:
-        raise OSError(f"cannot write mode {mode} as PNG") from e
+        msg = f"cannot write mode {mode} as PNG"
+        raise OSError(msg) from e
 
     #
     # write minimal PNG file
@@ -1358,7 +1380,8 @@ def _save(im, fp, filename, chunk=putchunk, save_all=False):
             if "transparency" in im.encoderinfo:
                 # don't bother with transparency if it's an RGBA
                 # and it's in the info dict. It's probably just stale.
-                raise OSError("cannot use transparency for this mode")
+                msg = "cannot use transparency for this mode"
+                raise OSError(msg)
     else:
         if im.mode == "P" and im.im.getpalettemode() == "RGBA":
             alpha = im.im.getpalette("RGBA", "A")

src/PIL/PpmImagePlugin.py

@@ -84,9 +84,11 @@ class PpmImageFile(ImageFile.ImageFile):
             token += c
         if not token:
             # Token was not even 1 byte
-            raise ValueError("Reached EOF while reading header")
+            msg = "Reached EOF while reading header"
+            raise ValueError(msg)
         elif len(token) > 10:
-            raise ValueError(f"Token too long in file header: {token.decode()}")
+            msg = f"Token too long in file header: {token.decode()}"
+            raise ValueError(msg)
         return token
 
     def _open(self):
@@ -94,7 +96,8 @@ class PpmImageFile(ImageFile.ImageFile):
         try:
             mode = MODES[magic_number]
         except KeyError:
-            raise SyntaxError("not a PPM file")
+            msg = "not a PPM file"
+            raise SyntaxError(msg)
 
         if magic_number in (b"P1", b"P4"):
             self.custom_mimetype = "image/x-portable-bitmap"
@@ -122,9 +125,8 @@ class PpmImageFile(ImageFile.ImageFile):
             elif ix == 2:  # token is maxval
                 maxval = token
                 if not 0 < maxval < 65536:
-                    raise ValueError(
-                        "maxval must be greater than 0 and less than 65536"
-                    )
+                    msg = "maxval must be greater than 0 and less than 65536"
+                    raise ValueError(msg)
                 if maxval > 255 and mode == "L":
                     self.mode = "I"
 
@@ -208,9 +210,8 @@ class PpmPlainDecoder(ImageFile.PyDecoder):
             tokens = b"".join(block.split())
             for token in tokens:
                 if token not in (48, 49):
-                    raise ValueError(
-                        b"Invalid token for this mode: %s" % bytes([token])
-                    )
+                    msg = b"Invalid token for this mode: %s" % bytes([token])
+                    raise ValueError(msg)
             data = (data + tokens)[:total_bytes]
         invert = bytes.maketrans(b"01", b"\xFF\x00")
         return data.translate(invert)
@@ -243,18 +244,19 @@ class PpmPlainDecoder(ImageFile.PyDecoder):
             if block and not block[-1:].isspace():  # block might split token
                 half_token = tokens.pop()  # save half token for later
                 if len(half_token) > max_len:  # prevent buildup of half_token
-                    raise ValueError(
+                    msg = (
                         b"Token too long found in data: %s" % half_token[: max_len + 1]
                     )
+                    raise ValueError(msg)
 
             for token in tokens:
                 if len(token) > max_len:
-                    raise ValueError(
-                        b"Token too long found in data: %s" % token[: max_len + 1]
-                    )
+                    msg = b"Token too long found in data: %s" % token[: max_len + 1]
+                    raise ValueError(msg)
                 value = int(token)
                 if value > maxval:
-                    raise ValueError(f"Channel value too large for this mode: {value}")
+                    msg = f"Channel value too large for this mode: {value}"
+                    raise ValueError(msg)
                 value = round(value / maxval * out_max)
                 data += o32(value) if self.mode == "I" else o8(value)
                 if len(data) == total_bytes:  # finished!
@@ -314,7 +316,8 @@ def _save(im, fp, filename):
     elif im.mode in ("RGB", "RGBA"):
         rawmode, head = "RGB", b"P6"
     else:
-        raise OSError(f"cannot write mode {im.mode} as PPM")
+        msg = f"cannot write mode {im.mode} as PPM"
+        raise OSError(msg)
     fp.write(head + b"\n%d %d\n" % im.size)
     if head == b"P6":
         fp.write(b"255\n")

src/PIL/PsdImagePlugin.py

@@ -65,7 +65,8 @@ class PsdImageFile(ImageFile.ImageFile):
 
         s = read(26)
         if not _accept(s) or i16(s, 4) != 1:
-            raise SyntaxError("not a PSD file")
+            msg = "not a PSD file"
+            raise SyntaxError(msg)
 
         psd_bits = i16(s, 22)
         psd_channels = i16(s, 12)
@@ -74,7 +75,8 @@ class PsdImageFile(ImageFile.ImageFile):
         mode, channels = MODES[(psd_mode, psd_bits)]
 
         if channels > psd_channels:
-            raise OSError("not enough channels")
+            msg = "not enough channels"
+            raise OSError(msg)
         if mode == "RGB" and psd_channels == 4:
             mode = "RGBA"
             channels = 4
@@ -152,7 +154,8 @@ class PsdImageFile(ImageFile.ImageFile):
             self.fp = self._fp
             return name, bbox
         except IndexError as e:
-            raise EOFError("no such layer") from e
+            msg = "no such layer"
+            raise EOFError(msg) from e
 
     def tell(self):
         # return layer number (0=image, 1..max=layers)
@@ -170,7 +173,8 @@ def _layerinfo(fp, ct_bytes):
 
     # sanity check
     if ct_bytes < (abs(ct) * 20):
-        raise SyntaxError("Layer block too short for number of layers requested")
+        msg = "Layer block too short for number of layers requested"
+        raise SyntaxError(msg)
 
     for _ in range(abs(ct)):
 

src/PIL/PyAccess.py

@@ -79,7 +79,8 @@ class PyAccess:
         :param color: The pixel value.
         """
         if self.readonly:
-            raise ValueError("Attempt to putpixel a read only image")
+            msg = "Attempt to putpixel a read only image"
+            raise ValueError(msg)
         (x, y) = xy
         if x < 0:
             x = self.xsize + x
@@ -127,7 +128,8 @@ class PyAccess:
     def check_xy(self, xy):
         (x, y) = xy
         if not (0 <= x < self.xsize and 0 <= y < self.ysize):
-            raise ValueError("pixel location out of range")
+            msg = "pixel location out of range"
+            raise ValueError(msg)
         return xy
 
 

src/PIL/SgiImagePlugin.py

@@ -60,7 +60,8 @@ class SgiImageFile(ImageFile.ImageFile):
         s = self.fp.read(headlen)
 
         if not _accept(s):
-            raise ValueError("Not an SGI image file")
+            msg = "Not an SGI image file"
+            raise ValueError(msg)
 
         # compression : verbatim or RLE
         compression = s[2]
@@ -91,7 +92,8 @@ class SgiImageFile(ImageFile.ImageFile):
             pass
 
         if rawmode == "":
-            raise ValueError("Unsupported SGI image mode")
+            msg = "Unsupported SGI image mode"
+            raise ValueError(msg)
 
         self._size = xsize, ysize
         self.mode = rawmode.split(";")[0]
@@ -124,7 +126,8 @@ class SgiImageFile(ImageFile.ImageFile):
 
 def _save(im, fp, filename):
     if im.mode != "RGB" and im.mode != "RGBA" and im.mode != "L":
-        raise ValueError("Unsupported SGI image mode")
+        msg = "Unsupported SGI image mode"
+        raise ValueError(msg)
 
     # Get the keyword arguments
     info = im.encoderinfo
@@ -133,7 +136,8 @@ def _save(im, fp, filename):
     bpc = info.get("bpc", 1)
 
     if bpc not in (1, 2):
-        raise ValueError("Unsupported number of bytes per pixel")
+        msg = "Unsupported number of bytes per pixel"
+        raise ValueError(msg)
 
     # Flip the image, since the origin of SGI file is the bottom-left corner
     orientation = -1
@@ -158,9 +162,8 @@ def _save(im, fp, filename):
 
     # assert we've got the right number of bands.
     if len(im.getbands()) != z:
-        raise ValueError(
-            f"incorrect number of bands in SGI write: {z} vs {len(im.getbands())}"
-        )
+        msg = f"incorrect number of bands in SGI write: {z} vs {len(im.getbands())}"
+        raise ValueError(msg)
 
     # Minimum Byte value
     pinmin = 0

src/PIL/SpiderImagePlugin.py

@@ -110,14 +110,17 @@ class SpiderImageFile(ImageFile.ImageFile):
                 t = struct.unpack("<27f", f)  # little-endian
                 hdrlen = isSpiderHeader(t)
             if hdrlen == 0:
-                raise SyntaxError("not a valid Spider file")
+                msg = "not a valid Spider file"
+                raise SyntaxError(msg)
         except struct.error as e:
-            raise SyntaxError("not a valid Spider file") from e
+            msg = "not a valid Spider file"
+            raise SyntaxError(msg) from e
 
         h = (99,) + t  # add 1 value : spider header index starts at 1
         iform = int(h[5])
         if iform != 1:
-            raise SyntaxError("not a Spider 2D image")
+            msg = "not a Spider 2D image"
+            raise SyntaxError(msg)
 
         self._size = int(h[12]), int(h[2])  # size in pixels (width, height)
         self.istack = int(h[24])
@@ -140,7 +143,8 @@ class SpiderImageFile(ImageFile.ImageFile):
             offset = hdrlen + self.stkoffset
             self.istack = 2  # So Image knows it's still a stack
         else:
-            raise SyntaxError("inconsistent stack header values")
+            msg = "inconsistent stack header values"
+            raise SyntaxError(msg)
 
         if self.bigendian:
             self.rawmode = "F;32BF"
@@ -168,7 +172,8 @@ class SpiderImageFile(ImageFile.ImageFile):
 
     def seek(self, frame):
         if self.istack == 0:
-            raise EOFError("attempt to seek in a non-stack file")
+            msg = "attempt to seek in a non-stack file"
+            raise EOFError(msg)
         if not self._seek_check(frame):
             return
         self.stkoffset = self.hdrlen + frame * (self.hdrlen + self.imgbytes)
@@ -260,7 +265,8 @@ def _save(im, fp, filename):
 
     hdr = makeSpiderHeader(im)
     if len(hdr) < 256:
-        raise OSError("Error creating Spider header")
+        msg = "Error creating Spider header"
+        raise OSError(msg)
 
     # write the SPIDER header
     fp.writelines(hdr)

src/PIL/SunImagePlugin.py

@@ -54,7 +54,8 @@ class SunImageFile(ImageFile.ImageFile):
         # HEAD
         s = self.fp.read(32)
         if not _accept(s):
-            raise SyntaxError("not an SUN raster file")
+            msg = "not an SUN raster file"
+            raise SyntaxError(msg)
 
         offset = 32
 
@@ -83,14 +84,17 @@ class SunImageFile(ImageFile.ImageFile):
             else:
                 self.mode, rawmode = "RGB", "BGRX"
         else:
-            raise SyntaxError("Unsupported Mode/Bit Depth")
+            msg = "Unsupported Mode/Bit Depth"
+            raise SyntaxError(msg)
 
         if palette_length:
             if palette_length > 1024:
-                raise SyntaxError("Unsupported Color Palette Length")
+                msg = "Unsupported Color Palette Length"
+                raise SyntaxError(msg)
 
             if palette_type != 1:
-                raise SyntaxError("Unsupported Palette Type")
+                msg = "Unsupported Palette Type"
+                raise SyntaxError(msg)
 
             offset = offset + palette_length
             self.palette = ImagePalette.raw("RGB;L", self.fp.read(palette_length))
@@ -124,7 +128,8 @@ class SunImageFile(ImageFile.ImageFile):
         elif file_type == 2:
             self.tile = [("sun_rle", (0, 0) + self.size, offset, rawmode)]
         else:
-            raise SyntaxError("Unsupported Sun Raster file type")
+            msg = "Unsupported Sun Raster file type"
+            raise SyntaxError(msg)
 
 
 #

src/PIL/TarIO.py

@@ -35,12 +35,14 @@ class TarIO(ContainerIO.ContainerIO):
 
             s = self.fh.read(512)
             if len(s) != 512:
-                raise OSError("unexpected end of tar file")
+                msg = "unexpected end of tar file"
+                raise OSError(msg)
 
             name = s[:100].decode("utf-8")
             i = name.find("\0")
             if i == 0:
-                raise OSError("cannot find subfile")
+                msg = "cannot find subfile"
+                raise OSError(msg)
             if i > 0:
                 name = name[:i]
 

src/PIL/TgaImagePlugin.py

@@ -73,7 +73,8 @@ class TgaImageFile(ImageFile.ImageFile):
             or self.size[1] <= 0
             or depth not in (1, 8, 16, 24, 32)
         ):
-            raise SyntaxError("not a TGA file")
+            msg = "not a TGA file"
+            raise SyntaxError(msg)
 
         # image mode
         if imagetype in (3, 11):
@@ -89,7 +90,8 @@ class TgaImageFile(ImageFile.ImageFile):
             if depth == 32:
                 self.mode = "RGBA"
         else:
-            raise SyntaxError("unknown TGA mode")
+            msg = "unknown TGA mode"
+            raise SyntaxError(msg)
 
         # orientation
         orientation = flags & 0x30
@@ -99,7 +101,8 @@ class TgaImageFile(ImageFile.ImageFile):
         elif orientation in [0, 0x10]:
             orientation = -1
         else:
-            raise SyntaxError("unknown TGA orientation")
+            msg = "unknown TGA orientation"
+            raise SyntaxError(msg)
 
         self.info["orientation"] = orientation
 
@@ -175,7 +178,8 @@ def _save(im, fp, filename):
     try:
         rawmode, bits, colormaptype, imagetype = SAVE[im.mode]
     except KeyError as e:
-        raise OSError(f"cannot write mode {im.mode} as TGA") from e
+        msg = f"cannot write mode {im.mode} as TGA"
+        raise OSError(msg) from e
 
     if "rle" in im.encoderinfo:
         rle = im.encoderinfo["rle"]

src/PIL/TiffImagePlugin.py

@@ -500,14 +500,16 @@ class ImageFileDirectory_v2(MutableMapping):
         :param prefix: Override the endianness of the file.
         """
         if not _accept(ifh):
-            raise SyntaxError(f"not a TIFF file (header {repr(ifh)} not valid)")
+            msg = f"not a TIFF file (header {repr(ifh)} not valid)"
+            raise SyntaxError(msg)
         self._prefix = prefix if prefix is not None else ifh[:2]
         if self._prefix == MM:
             self._endian = ">"
         elif self._prefix == II:
             self._endian = "<"
         else:
-            raise SyntaxError("not a TIFF IFD")
+            msg = "not a TIFF IFD"
+            raise SyntaxError(msg)
         self._bigtiff = ifh[2] == 43
         self.group = group
         self.tagtype = {}
@@ -524,7 +526,8 @@ class ImageFileDirectory_v2(MutableMapping):
 
     @legacy_api.setter
     def legacy_api(self, value):
-        raise Exception("Not allowing setting of legacy api")
+        msg = "Not allowing setting of legacy api"
+        raise Exception(msg)
 
     def reset(self):
         self._tags_v1 = {}  # will remain empty if legacy_api is false
@@ -732,6 +735,8 @@ class ImageFileDirectory_v2(MutableMapping):
     @_register_writer(2)
     def write_string(self, value):
         # remerge of https://github.com/python-pillow/Pillow/pull/1416
+        if isinstance(value, int):
+            value = str(value)
         if not isinstance(value, bytes):
             value = value.encode("ascii", "replace")
         return value + b"\0"
@@ -778,10 +783,11 @@ class ImageFileDirectory_v2(MutableMapping):
     def _ensure_read(self, fp, size):
         ret = fp.read(size)
         if len(ret) != size:
-            raise OSError(
+            msg = (
                 "Corrupt EXIF data.  "
                 f"Expecting to read {size} bytes but only got {len(ret)}. "
             )
+            raise OSError(msg)
         return ret
 
     def load(self, fp):
@@ -908,7 +914,8 @@ class ImageFileDirectory_v2(MutableMapping):
         if stripoffsets is not None:
             tag, typ, count, value, data = entries[stripoffsets]
             if data:
-                raise NotImplementedError("multistrip support not yet implemented")
+                msg = "multistrip support not yet implemented"
+                raise NotImplementedError(msg)
             value = self._pack("L", self._unpack("L", value)[0] + offset)
             entries[stripoffsets] = tag, typ, count, value, data
 
@@ -1121,7 +1128,8 @@ class TiffImageFile(ImageFile.ImageFile):
 
         while len(self._frame_pos) <= frame:
             if not self.__next:
-                raise EOFError("no more images in TIFF file")
+                msg = "no more images in TIFF file"
+                raise EOFError(msg)
             logger.debug(
                 f"Seeking to frame {frame}, on frame {self.__frame}, "
                 f"__next {self.__next}, location: {self.fp.tell()}"
@@ -1228,7 +1236,8 @@ class TiffImageFile(ImageFile.ImageFile):
         self.load_prepare()
 
         if not len(self.tile) == 1:
-            raise OSError("Not exactly one tile")
+            msg = "Not exactly one tile"
+            raise OSError(msg)
 
         # (self._compression, (extents tuple),
         #   0, (rawmode, self._compression, fp))
@@ -1260,7 +1269,8 @@ class TiffImageFile(ImageFile.ImageFile):
         try:
             decoder.setimage(self.im, extents)
         except ValueError as e:
-            raise OSError("Couldn't set the image") from e
+            msg = "Couldn't set the image"
+            raise OSError(msg) from e
 
         close_self_fp = self._exclusive_fp and not self.is_animated
         if hasattr(self.fp, "getvalue"):
@@ -1314,7 +1324,8 @@ class TiffImageFile(ImageFile.ImageFile):
         """Setup this image object based on current tags"""
 
         if 0xBC01 in self.tag_v2:
-            raise OSError("Windows Media Photo files not yet supported")
+            msg = "Windows Media Photo files not yet supported"
+            raise OSError(msg)
 
         # extract relevant tags
         self._compression = COMPRESSION_INFO[self.tag_v2.get(COMPRESSION, 1)]
@@ -1373,7 +1384,8 @@ class TiffImageFile(ImageFile.ImageFile):
             logger.error(
                 "More samples per pixel than can be decoded: %s", samples_per_pixel
             )
-            raise SyntaxError("Invalid value for samples per pixel")
+            msg = "Invalid value for samples per pixel"
+            raise SyntaxError(msg)
 
         if samples_per_pixel < bps_actual_count:
             # If a file has more values in bps_tuple than expected,
@@ -1385,7 +1397,8 @@ class TiffImageFile(ImageFile.ImageFile):
             bps_tuple = bps_tuple * samples_per_pixel
 
         if len(bps_tuple) != samples_per_pixel:
-            raise SyntaxError("unknown data organization")
+            msg = "unknown data organization"
+            raise SyntaxError(msg)
 
         # mode: check photometric interpretation and bits per pixel
         key = (
@@ -1401,7 +1414,8 @@ class TiffImageFile(ImageFile.ImageFile):
             self.mode, rawmode = OPEN_INFO[key]
         except KeyError as e:
             logger.debug("- unsupported format")
-            raise SyntaxError("unknown pixel mode") from e
+            msg = "unknown pixel mode"
+            raise SyntaxError(msg) from e
 
         logger.debug(f"- raw mode: {rawmode}")
         logger.debug(f"- pil mode: {self.mode}")
@@ -1517,7 +1531,8 @@ class TiffImageFile(ImageFile.ImageFile):
                         layer += 1
         else:
             logger.debug("- unsupported data organization")
-            raise SyntaxError("unknown data organization")
+            msg = "unknown data organization"
+            raise SyntaxError(msg)
 
         # Fix up info.
         if ICCPROFILE in self.tag_v2:
@@ -1569,7 +1584,8 @@ def _save(im, fp, filename):
     try:
         rawmode, prefix, photo, format, bits, extra = SAVE_INFO[im.mode]
     except KeyError as e:
-        raise OSError(f"cannot write mode {im.mode} as TIFF") from e
+        msg = f"cannot write mode {im.mode} as TIFF"
+        raise OSError(msg) from e
 
     ifd = ImageFileDirectory_v2(prefix=prefix)
 
@@ -1734,11 +1750,11 @@ def _save(im, fp, filename):
         if "quality" in encoderinfo:
             quality = encoderinfo["quality"]
             if not isinstance(quality, int) or quality < 0 or quality > 100:
-                raise ValueError("Invalid quality setting")
+                msg = "Invalid quality setting"
+                raise ValueError(msg)
             if compression != "jpeg":
-                raise ValueError(
-                    "quality setting only supported for 'jpeg' compression"
-                )
+                msg = "quality setting only supported for 'jpeg' compression"
+                raise ValueError(msg)
             ifd[JPEGQUALITY] = quality
 
         logger.debug("Saving using libtiff encoder")
@@ -1835,7 +1851,8 @@ def _save(im, fp, filename):
             if s:
                 break
         if s < 0:
-            raise OSError(f"encoder error {s} when writing image file")
+            msg = f"encoder error {s} when writing image file"
+            raise OSError(msg)
 
     else:
         for tag in blocklist:
@@ -1910,7 +1927,8 @@ class AppendingTiffWriter:
         elif iimm == b"MM\x00\x2a":
             self.setEndian(">")
         else:
-            raise RuntimeError("Invalid TIFF file header")
+            msg = "Invalid TIFF file header"
+            raise RuntimeError(msg)
 
         self.skipIFDs()
         self.goToEnd()
@@ -1924,12 +1942,14 @@ class AppendingTiffWriter:
 
         iimm = self.f.read(4)
         if not iimm:
-            # raise RuntimeError("nothing written into new page")
+            # msg = "nothing written into new page"
+            # raise RuntimeError(msg)
             # Make it easy to finish a frame without committing to a new one.
             return
 
         if iimm != self.IIMM:
-            raise RuntimeError("IIMM of new page doesn't match IIMM of first page")
+            msg = "IIMM of new page doesn't match IIMM of first page"
+            raise RuntimeError(msg)
 
         ifd_offset = self.readLong()
         ifd_offset += self.offsetOfNewPage
@@ -2003,29 +2023,34 @@ class AppendingTiffWriter:
         self.f.seek(-2, os.SEEK_CUR)
         bytes_written = self.f.write(struct.pack(self.longFmt, value))
         if bytes_written is not None and bytes_written != 4:
-            raise RuntimeError(f"wrote only {bytes_written} bytes but wanted 4")
+            msg = f"wrote only {bytes_written} bytes but wanted 4"
+            raise RuntimeError(msg)
 
     def rewriteLastShort(self, value):
         self.f.seek(-2, os.SEEK_CUR)
         bytes_written = self.f.write(struct.pack(self.shortFmt, value))
         if bytes_written is not None and bytes_written != 2:
-            raise RuntimeError(f"wrote only {bytes_written} bytes but wanted 2")
+            msg = f"wrote only {bytes_written} bytes but wanted 2"
+            raise RuntimeError(msg)
 
     def rewriteLastLong(self, value):
         self.f.seek(-4, os.SEEK_CUR)
         bytes_written = self.f.write(struct.pack(self.longFmt, value))
         if bytes_written is not None and bytes_written != 4:
-            raise RuntimeError(f"wrote only {bytes_written} bytes but wanted 4")
+            msg = f"wrote only {bytes_written} bytes but wanted 4"
+            raise RuntimeError(msg)
 
     def writeShort(self, value):
         bytes_written = self.f.write(struct.pack(self.shortFmt, value))
         if bytes_written is not None and bytes_written != 2:
-            raise RuntimeError(f"wrote only {bytes_written} bytes but wanted 2")
+            msg = f"wrote only {bytes_written} bytes but wanted 2"
+            raise RuntimeError(msg)
 
     def writeLong(self, value):
         bytes_written = self.f.write(struct.pack(self.longFmt, value))
         if bytes_written is not None and bytes_written != 4:
-            raise RuntimeError(f"wrote only {bytes_written} bytes but wanted 4")
+            msg = f"wrote only {bytes_written} bytes but wanted 4"
+            raise RuntimeError(msg)
 
     def close(self):
         self.finalize()
@@ -2068,7 +2093,8 @@ class AppendingTiffWriter:
 
     def fixOffsets(self, count, isShort=False, isLong=False):
         if not isShort and not isLong:
-            raise RuntimeError("offset is neither short nor long")
+            msg = "offset is neither short nor long"
+            raise RuntimeError(msg)
 
         for i in range(count):
             offset = self.readShort() if isShort else self.readLong()
@@ -2076,7 +2102,8 @@ class AppendingTiffWriter:
             if isShort and offset >= 65536:
                 # offset is now too large - we must convert shorts to longs
                 if count != 1:
-                    raise RuntimeError("not implemented")  # XXX TODO
+                    msg = "not implemented"
+                    raise RuntimeError(msg)  # XXX TODO
 
                 # simple case - the offset is just one and therefore it is
                 # local (not referenced with another offset)

src/PIL/WebPImagePlugin.py

@@ -130,7 +130,8 @@ class WebPImageFile(ImageFile.ImageFile):
         if ret is None:
             self._reset()  # Reset just to be safe
             self.seek(0)
-            raise EOFError("failed to decode next frame in WebP file")
+            msg = "failed to decode next frame in WebP file"
+            raise EOFError(msg)
 
         # Compute duration
         data, timestamp = ret
@@ -233,9 +234,8 @@ def _save_all(im, fp, filename):
         or len(background) != 4
         or not all(0 <= v < 256 for v in background)
     ):
-        raise OSError(
-            f"Background color is not an RGBA tuple clamped to (0-255): {background}"
-        )
+        msg = f"Background color is not an RGBA tuple clamped to (0-255): {background}"
+        raise OSError(msg)
 
     # Convert to packed uint
     bg_r, bg_g, bg_b, bg_a = background
@@ -311,7 +311,8 @@ def _save_all(im, fp, filename):
     # Get the final output from the encoder
     data = enc.assemble(icc_profile, exif, xmp)
     if data is None:
-        raise OSError("cannot write file as WebP (encoder returned None)")
+        msg = "cannot write file as WebP (encoder returned None)"
+        raise OSError(msg)
 
     fp.write(data)
 
@@ -351,7 +352,8 @@ def _save(im, fp, filename):
         xmp,
     )
     if data is None:
-        raise OSError("cannot write file as WebP (encoder returned None)")
+        msg = "cannot write file as WebP (encoder returned None)"
+        raise OSError(msg)
 
     fp.write(data)
 

src/PIL/WmfImagePlugin.py

@@ -109,7 +109,8 @@ class WmfStubImageFile(ImageFile.StubImageFile):
 
             # sanity check (standard metafile header)
             if s[22:26] != b"\x01\x00\t\x00":
-                raise SyntaxError("Unsupported WMF file format")
+                msg = "Unsupported WMF file format"
+                raise SyntaxError(msg)
 
         elif s[:4] == b"\x01\x00\x00\x00" and s[40:44] == b" EMF":
             # enhanced metafile
@@ -137,7 +138,8 @@ class WmfStubImageFile(ImageFile.StubImageFile):
                 self.info["dpi"] = xdpi, ydpi
 
         else:
-            raise SyntaxError("Unsupported file format")
+            msg = "Unsupported file format"
+            raise SyntaxError(msg)
 
         self.mode = "RGB"
         self._size = size
@@ -162,7 +164,8 @@ class WmfStubImageFile(ImageFile.StubImageFile):
 
 def _save(im, fp, filename):
     if _handler is None or not hasattr(_handler, "save"):
-        raise OSError("WMF save handler not installed")
+        msg = "WMF save handler not installed"
+        raise OSError(msg)
     _handler.save(im, fp, filename)
 
 

src/PIL/XVThumbImagePlugin.py

@@ -49,7 +49,8 @@ class XVThumbImageFile(ImageFile.ImageFile):
 
         # check magic
         if not _accept(self.fp.read(6)):
-            raise SyntaxError("not an XV thumbnail file")
+            msg = "not an XV thumbnail file"
+            raise SyntaxError(msg)
 
         # Skip to beginning of next line
         self.fp.readline()
@@ -58,7 +59,8 @@ class XVThumbImageFile(ImageFile.ImageFile):
         while True:
             s = self.fp.readline()
             if not s:
-                raise SyntaxError("Unexpected EOF reading XV thumbnail file")
+                msg = "Unexpected EOF reading XV thumbnail file"
+                raise SyntaxError(msg)
             if s[0] != 35:  # ie. when not a comment: '#'
                 break
 

src/PIL/XbmImagePlugin.py

@@ -53,7 +53,8 @@ class XbmImageFile(ImageFile.ImageFile):
         m = xbm_head.match(self.fp.read(512))
 
         if not m:
-            raise SyntaxError("not a XBM file")
+            msg = "not a XBM file"
+            raise SyntaxError(msg)
 
         xsize = int(m.group("width"))
         ysize = int(m.group("height"))
@@ -70,7 +71,8 @@ class XbmImageFile(ImageFile.ImageFile):
 def _save(im, fp, filename):
 
     if im.mode != "1":
-        raise OSError(f"cannot write mode {im.mode} as XBM")
+        msg = f"cannot write mode {im.mode} as XBM"
+        raise OSError(msg)
 
     fp.write(f"#define im_width {im.size[0]}\n".encode("ascii"))
     fp.write(f"#define im_height {im.size[1]}\n".encode("ascii"))

src/PIL/XpmImagePlugin.py

@@ -40,13 +40,15 @@ class XpmImageFile(ImageFile.ImageFile):
     def _open(self):
 
         if not _accept(self.fp.read(9)):
-            raise SyntaxError("not an XPM file")
+            msg = "not an XPM file"
+            raise SyntaxError(msg)
 
         # skip forward to next string
         while True:
             s = self.fp.readline()
             if not s:
-                raise SyntaxError("broken XPM file")
+                msg = "broken XPM file"
+                raise SyntaxError(msg)
             m = xpm_head.match(s)
             if m:
                 break
@@ -57,7 +59,8 @@ class XpmImageFile(ImageFile.ImageFile):
         bpp = int(m.group(4))
 
         if pal > 256 or bpp != 1:
-            raise ValueError("cannot read this XPM file")
+            msg = "cannot read this XPM file"
+            raise ValueError(msg)
 
         #
         # load palette description
@@ -91,13 +94,15 @@ class XpmImageFile(ImageFile.ImageFile):
                         )
                     else:
                         # unknown colour
-                        raise ValueError("cannot read this XPM file")
+                        msg = "cannot read this XPM file"
+                        raise ValueError(msg)
                     break
 
             else:
 
                 # missing colour key
-                raise ValueError("cannot read this XPM file")
+                msg = "cannot read this XPM file"
+                raise ValueError(msg)
 
         self.mode = "P"
         self.palette = ImagePalette.raw("RGB", b"".join(palette))

src/PIL/_deprecate.py

@@ -43,14 +43,17 @@ def deprecate(
     if when is None:
         removed = "a future version"
     elif when <= int(__version__.split(".")[0]):
-        raise RuntimeError(f"{deprecated} {is_} deprecated and should be removed.")
+        msg = f"{deprecated} {is_} deprecated and should be removed."
+        raise RuntimeError(msg)
     elif when == 10:
         removed = "Pillow 10 (2023-07-01)"
     else:
-        raise ValueError(f"Unknown removal version, update {__name__}?")
+        msg = f"Unknown removal version, update {__name__}?"
+        raise ValueError(msg)
 
     if replacement and action:
-        raise ValueError("Use only one of 'replacement' and 'action'")
+        msg = "Use only one of 'replacement' and 'action'"
+        raise ValueError(msg)
 
     if replacement:
         action = f". Use {replacement} instead."

src/PIL/features.py

@@ -25,7 +25,8 @@ def check_module(feature):
     :raises ValueError: If the module is not defined in this version of Pillow.
     """
     if not (feature in modules):
-        raise ValueError(f"Unknown module {feature}")
+        msg = f"Unknown module {feature}"
+        raise ValueError(msg)
 
     module, ver = modules[feature]
 
@@ -78,7 +79,8 @@ def check_codec(feature):
     :raises ValueError: If the codec is not defined in this version of Pillow.
     """
     if feature not in codecs:
-        raise ValueError(f"Unknown codec {feature}")
+        msg = f"Unknown codec {feature}"
+        raise ValueError(msg)
 
     codec, lib = codecs[feature]
 
@@ -135,7 +137,8 @@ def check_feature(feature):
     :raises ValueError: If the feature is not defined in this version of Pillow.
     """
     if feature not in features:
-        raise ValueError(f"Unknown feature {feature}")
+        msg = f"Unknown feature {feature}"
+        raise ValueError(msg)
 
     module, flag, ver = features[feature]
 

src/_imaging.c

@@ -1531,25 +1531,21 @@ if (PySequence_Check(op)) { \
                 PyErr_SetString(PyExc_TypeError, must_be_sequence);
                 return NULL;
             }
+            int endian = strncmp(image->mode, "I;16", 4) == 0 ? (strcmp(image->mode, "I;16B") == 0 ? 2 : 1) : 0;
             double value;
-            if (scale == 1.0 && offset == 0.0) {
-                /* Clipped data */
-                for (i = x = y = 0; i < n; i++) {
-                    set_value_to_item(seq, i);
-                    image->image8[y][x] = (UINT8)CLIP8(value);
-                    if (++x >= (int)image->xsize) {
-                        x = 0, y++;
-                    }
+            for (i = x = y = 0; i < n; i++) {
+                set_value_to_item(seq, i);
+                if (scale != 1.0 || offset != 0.0) {
+                    value = value * scale + offset;
                 }
-
-            } else {
-                /* Scaled and clipped data */
-                for (i = x = y = 0; i < n; i++) {
-                    set_value_to_item(seq, i);
-                    image->image8[y][x] = CLIP8(value * scale + offset);
-                    if (++x >= (int)image->xsize) {
-                        x = 0, y++;
-                    }
+                if (endian == 0) {
+                    image->image8[y][x] = (UINT8)CLIP8(value);
+                } else {
+                    image->image8[y][x * 2 + (endian == 2 ? 1 : 0)] = CLIP8((int)value % 256);
+                    image->image8[y][x * 2 + (endian == 2 ? 0 : 1)] = CLIP8((int)value >> 8);
+                }
+                if (++x >= (int)image->xsize) {
+                    x = 0, y++;
                 }
             }
             PyErr_Clear(); /* Avoid weird exceptions */

src/encode.c

@@ -1212,11 +1212,12 @@ PyImaging_Jpeg2KEncoderNew(PyObject *self, PyObject *args) {
     char *cinema_mode = "no";
     OPJ_CINEMA_MODE cine_mode;
     char mct = 0;
+    int sgnd = 0;
     Py_ssize_t fd = -1;
 
     if (!PyArg_ParseTuple(
             args,
-            "ss|OOOsOnOOOssbn",
+            "ss|OOOsOnOOOssbbn",
             &mode,
             &format,
             &offset,
@@ -1231,6 +1232,7 @@ PyImaging_Jpeg2KEncoderNew(PyObject *self, PyObject *args) {
             &progression,
             &cinema_mode,
             &mct,
+            &sgnd,
             &fd)) {
         return NULL;
     }
@@ -1329,6 +1331,7 @@ PyImaging_Jpeg2KEncoderNew(PyObject *self, PyObject *args) {
     context->progression = prog_order;
     context->cinema_mode = cine_mode;
     context->mct = mct;
+    context->sgnd = sgnd;
 
     return (PyObject *)encoder;
 }

src/libImaging/Convert.c

@@ -479,6 +479,25 @@ rgba2rgbA(UINT8 *out, const UINT8 *in, int xsize) {
     }
 }
 
+static void
+rgba2rgb_(UINT8 *out, const UINT8 *in, int xsize) {
+    int x;
+    unsigned int alpha;
+    for (x = 0; x < xsize; x++, in += 4) {
+        alpha = in[3];
+        if (alpha == 255 || alpha == 0) {
+            *out++ = in[0];
+            *out++ = in[1];
+            *out++ = in[2];
+        } else {
+            *out++ = CLIP8((255 * in[0]) / alpha);
+            *out++ = CLIP8((255 * in[1]) / alpha);
+            *out++ = CLIP8((255 * in[2]) / alpha);
+        }
+        *out++ = 255;
+    }
+}
+
 /*
  * Conversion of RGB + single transparent color to RGBA,
  * where any pixel that matches the color will have the
@@ -934,6 +953,7 @@ static struct {
     {"RGBA", "HSV", rgb2hsv},
 
     {"RGBa", "RGBA", rgba2rgbA},
+    {"RGBa", "RGB", rgba2rgb_},
 
     {"RGBX", "1", rgb2bit},
     {"RGBX", "L", rgb2l},

src/libImaging/Jpeg2K.h

@@ -85,6 +85,9 @@ typedef struct {
     /* Set multiple component transformation */
     char mct;
 
+    /* Signed */
+    int sgnd;
+
     /* Progression order (LRCP/RLCP/RPCL/PCRL/CPRL) */
     OPJ_PROG_ORDER progression;
 

src/libImaging/Jpeg2KEncode.c

@@ -343,7 +343,7 @@ j2k_encode_entry(Imaging im, ImagingCodecState state) {
         image_params[n].x0 = image_params[n].y0 = 0;
         image_params[n].prec = prec;
         image_params[n].bpp = bpp;
-        image_params[n].sgnd = 0;
+        image_params[n].sgnd = context->sgnd == 0 ? 0 : 1;
     }
 
     image = opj_image_create(components, image_params, color_space);

winbuild/build_prepare.py

@@ -289,7 +289,7 @@ deps = {
         # "bins": [r"objs\{msbuild_arch}\Release\freetype.dll"],
     },
     "lcms2": {
-        "url": SF_PROJECTS + "/lcms/files/lcms/2.13/lcms2-2.14.tar.gz/download",
+        "url": SF_PROJECTS + "/lcms/files/lcms/2.14/lcms2-2.14.tar.gz/download",
         "filename": "lcms2-2.14.tar.gz",
         "dir": "lcms2-2.14",
         "license": "COPYING",
@@ -319,6 +319,11 @@ deps = {
         "filename": "openjpeg-2.5.0.tar.gz",
         "dir": "openjpeg-2.5.0",
         "license": "LICENSE",
+        "patch": {
+            r"src\lib\openjp2\ht_dec.c": {
+                "#ifdef OPJ_COMPILER_MSVC\n    return (OPJ_UINT32)__popcnt(val);": "#if defined(OPJ_COMPILER_MSVC) && (defined(_M_IX86) || defined(_M_AMD64))\n    return (OPJ_UINT32)__popcnt(val);",  # noqa: E501
+            }
+        },
         "build": [
             cmd_cmake(("-DBUILD_CODEC:BOOL=OFF", "-DBUILD_SHARED_LIBS:BOOL=OFF")),
             cmd_nmake(target="clean"),
@@ -473,7 +478,8 @@ def extract_dep(url, filename):
                 member_abspath = os.path.abspath(os.path.join(sources_dir, member))
                 member_prefix = os.path.commonpath([sources_dir_abs, member_abspath])
                 if sources_dir_abs != member_prefix:
-                    raise RuntimeError("Attempted Path Traversal in Zip File")
+                    msg = "Attempted Path Traversal in Zip File"
+                    raise RuntimeError(msg)
             zf.extractall(sources_dir)
     elif filename.endswith(".tar.gz") or filename.endswith(".tgz"):
         with tarfile.open(file, "r:gz") as tgz:
@@ -481,10 +487,12 @@ def extract_dep(url, filename):
                 member_abspath = os.path.abspath(os.path.join(sources_dir, member))
                 member_prefix = os.path.commonpath([sources_dir_abs, member_abspath])
                 if sources_dir_abs != member_prefix:
-                    raise RuntimeError("Attempted Path Traversal in Tar File")
+                    msg = "Attempted Path Traversal in Tar File"
+                    raise RuntimeError(msg)
             tgz.extractall(sources_dir)
     else:
-        raise RuntimeError("Unknown archive type: " + filename)
+        msg = "Unknown archive type: " + filename
+        raise RuntimeError(msg)
 
 
 def write_script(name, lines):
@@ -621,7 +629,8 @@ if __name__ == "__main__":
         elif arg == "--srcdir":
             sources_dir = os.path.sep + "src"
         else:
-            raise ValueError("Unknown parameter: " + arg)
+            msg = "Unknown parameter: " + arg
+            raise ValueError(msg)
 
     # dependency cache directory
     os.makedirs(depends_dir, exist_ok=True)
@@ -637,9 +646,8 @@ if __name__ == "__main__":
 
     msvs = find_msvs()
     if msvs is None:
-        raise RuntimeError(
-            "Visual Studio not found. Please install Visual Studio 2017 or newer."
-        )
+        msg = "Visual Studio not found. Please install Visual Studio 2017 or newer."
+        raise RuntimeError(msg)
     print("Found Visual Studio at:", msvs["vs_dir"])
 
     print("Using output directory:", build_dir)