Allow for sys.stdout.buffer to be missing

Tests/test_file_png.py

@@ -713,13 +713,20 @@ class TestFilePng:
             with pytest.raises(EOFError):
                 im.seek(1)
 
-    def test_save_stdout(self):
+    @pytest.mark.parametrize("buffer", (True, False))
+    def test_save_stdout(self, buffer):
         old_stdout = sys.stdout.buffer
 
-        class MyStdOut:
+        if buffer:
-            buffer = BytesIO()
 
-        sys.stdout = mystdout = MyStdOut()
+            class MyStdOut:
+                buffer = BytesIO()
+
+            mystdout = MyStdOut()
+        else:
+            mystdout = BytesIO()
+
+        sys.stdout = mystdout
 
         with Image.open(TEST_PNG_FILE) as im:
             im.save(sys.stdout, "PNG")
@@ -727,7 +734,9 @@ class TestFilePng:
         # Reset stdout
         sys.stdout = old_stdout
 
-        reloaded = Image.open(mystdout.buffer)
+        if buffer:
+            mystdout = mystdout.buffer
+        reloaded = Image.open(mystdout)
         assert_image_equal_tofile(reloaded, TEST_PNG_FILE)
 
 

Tests/test_psdraw.py

@@ -2,6 +2,8 @@ import os
 import sys
 from io import BytesIO
 
+import pytest
+
 from PIL import Image, PSDraw
 
 
@@ -44,14 +46,21 @@ def test_draw_postscript(tmp_path):
     assert os.path.getsize(tempfile) > 0
 
 
-def test_stdout():
+@pytest.mark.parametrize("buffer", (True, False))
+def test_stdout(buffer):
     # Temporarily redirect stdout
     old_stdout = sys.stdout.buffer
 
-    class MyStdOut:
+    if buffer:
-        buffer = BytesIO()
 
-    sys.stdout = mystdout = MyStdOut()
+        class MyStdOut:
+            buffer = BytesIO()
+
+        mystdout = MyStdOut()
+    else:
+        mystdout = BytesIO()
+
+    sys.stdout = mystdout
 
     ps = PSDraw.PSDraw()
     _create_document(ps)
@@ -59,4 +68,6 @@ def test_stdout():
     # Reset stdout
     sys.stdout = old_stdout
 
-    assert mystdout.buffer.getvalue() != b""
+    if buffer:
+        mystdout = mystdout.buffer
+    assert mystdout.getvalue() != b""

docs/handbook/tutorial.rst

@@ -424,7 +424,7 @@ Drawing PostScript
         title = "hopper"
         box = (1*72, 2*72, 7*72, 10*72) # in points
 
-        ps = PSDraw.PSDraw() # default is sys.stdout.buffer
+        ps = PSDraw.PSDraw() # default is sys.stdout or sys.stdout.buffer
         ps.begin_document(title)
 
         # draw the image (75 dpi)

src/PIL/Image.py

@@ -2136,7 +2136,10 @@ class Image:
             filename = str(fp)
             open_fp = True
         elif fp == sys.stdout:
-            fp = sys.stdout.buffer
+            try:
+                fp = sys.stdout.buffer
+            except AttributeError:
+                pass
         if not filename and hasattr(fp, "name") and isPath(fp.name):
             # only set the name for metadata purposes
             filename = fp.name

src/PIL/ImageFile.py

@@ -493,7 +493,7 @@ def _save(im, fp, tile, bufsize=0):
     # But, it would need at least the image size in most cases. RawEncode is
     # a tricky case.
     bufsize = max(MAXBLOCK, bufsize, im.size[0] * 4)  # see RawEncode.c
-    if fp == sys.stdout.buffer:
+    if fp == sys.stdout or (hasattr(sys.stdout, "buffer") and fp == sys.stdout.buffer):
         fp.flush()
         return
     try:

src/PIL/PSDraw.py

@@ -26,12 +26,15 @@ from . import EpsImagePlugin
 class PSDraw:
     """
     Sets up printing to the given file. If ``fp`` is omitted,
-    ``sys.stdout.buffer`` is assumed.
+    ``sys.stdout.buffer`` or ``sys.stdout`` is assumed.
     """
 
     def __init__(self, fp=None):
         if not fp:
-            fp = sys.stdout.buffer
+            try:
+                fp = sys.stdout.buffer
+            except AttributeError:
+                fp = sys.stdout
         self.fp = fp
 
     def begin_document(self, id=None):