Do not write custom tags with libtiff < 4

Tests/test_file_libtiff.py

@@ -8,6 +8,7 @@ import io
 import logging
 import itertools
 import os
+import distutils.version
 
 from PIL import Image, TiffImagePlugin, TiffTags
 
@@ -236,7 +237,15 @@ class TestFileLibTiff(LibTiffTestCase):
             37000: 4,
             37001: 4.2
         }
-        for libtiff in [False, True]:
+
+        libtiff_version = TiffImagePlugin._libtiff_version()
+
+        libtiffs = [False]
+        if distutils.version.StrictVersion(libtiff_version) >= \
+           distutils.version.StrictVersion("4.0"):
+            libtiffs.append(True)
+
+        for libtiff in libtiffs:
             TiffImagePlugin.WRITE_LIBTIFF = libtiff
 
             im = hopper()

Tests/versions.py

@@ -10,6 +10,7 @@ def version(module, version):
 
 version(Image, "jpeglib")
 version(Image, "zlib")
+version(Image, "libtiff")
 
 try:
     from PIL import ImageFont

src/PIL/TiffImagePlugin.py

@@ -54,6 +54,7 @@ import os
 import struct
 import sys
 import warnings
+import distutils.version
 
 from .TiffTags import TYPES
 
@@ -284,6 +285,10 @@ def _limit_rational(val, max_val):
     return n_d[::-1] if inv else n_d
 
 
+def _libtiff_version():
+    return Image.core.libtiff_version.split("\n")[0].split("Version ")[1]
+
+
 ##
 # Wrapper for TIFF IFDs.
 
@@ -1501,9 +1506,11 @@ def _save(im, fp, filename):
             # Libtiff can only process certain core items without adding
             # them to the custom dictionary. Support has only been been added
             # for int and float values
-            if tag not in TiffTags.LIBTIFF_CORE and not \
-               (isinstance(value, int) or isinstance(value, float)):
-                continue
+            if tag not in TiffTags.LIBTIFF_CORE:
+                if (distutils.version.StrictVersion(_libtiff_version()) <
+                    distutils.version.StrictVersion("4.0")) \
+                   or not (isinstance(value, int) or isinstance(value, float)):
+                    continue
             if tag not in atts and tag not in blocklist:
                 if isinstance(value, str if py3 else unicode):
                     atts[tag] = value.encode('ascii', 'replace') + b"\0"

src/_imaging.c

@@ -3849,6 +3849,13 @@ setup_module(PyObject* m) {
   }
 #endif
 
+#ifdef HAVE_LIBTIFF
+  {
+    extern const char * ImagingTiffVersion(void);
+    PyDict_SetItemString(d, "libtiff_version", PyUnicode_FromString(ImagingTiffVersion()));
+  }
+#endif
+
     PyDict_SetItemString(d, "PILLOW_VERSION", PyUnicode_FromString(version));
 
     return 0;

src/libImaging/TiffDecode.c

@@ -406,13 +406,20 @@ int ImagingLibTiffMergeFieldInfo(ImagingCodecState state, TIFFDataType field_typ
     TIFFSTATE *clientstate = (TIFFSTATE *)state->context;
     char field_name[10];
     uint32 n;
+    int status = 0;
 
     const TIFFFieldInfo info[] = {
         { key, 0, 1, field_type, FIELD_CUSTOM, 1, 0, field_name }
     };
     n = sizeof(info) / sizeof(info[0]);
 
-    return TIFFMergeFieldInfo(clientstate->tiff, info, n);
+    // Test for libtiff 4.0 or later, excluding libtiff 3.9.6 and 3.9.7
+#if TIFFLIB_VERSION >= 20111221 && TIFFLIB_VERSION != 20120218 && TIFFLIB_VERSION != 20120922
+    status = TIFFMergeFieldInfo(clientstate->tiff, info, n);
+#else
+    TIFFMergeFieldInfo(clientstate->tiff, info, n);
+#endif
+    return status;
 }
 
 int ImagingLibTiffSetField(ImagingCodecState state, ttag_t tag, ...){
@@ -514,4 +521,11 @@ int ImagingLibTiffEncode(Imaging im, ImagingCodecState state, UINT8* buffer, int
     state->errcode = IMAGING_CODEC_END;
     return 0;
 }
+
+const char*
+ImagingTiffVersion(void)
+{
+    return TIFFGetVersion();
+}
+
 #endif