Merge pull request #5919 from radarhere/duplicate

Remove consecutive duplicates that only differ by their offset

Tests/test_file_tiff.py

@@ -3,7 +3,7 @@
 
 import pytest
 
-from PIL import Image, TiffImagePlugin
+from PIL import Image, ImageFile, TiffImagePlugin
 from PIL.TiffImagePlugin import RESOLUTION_UNIT, X_RESOLUTION, Y_RESOLUTION
 
 from .helper import (
@@ -726,6 +726,14 @@ def test_string_dimension(self):
             with pytest.raises(OSError):
                 im.load()
 
+    @pytest.mark.timeout(6)
+    @pytest.mark.filterwarnings("ignore:Truncated File Read")
+    def test_timeout(self):
+        with Image.open("Tests/images/timeout-6646305047838720") as im:
+            ImageFile.LOAD_TRUNCATED_IMAGES = True
+            im.load()
+            ImageFile.LOAD_TRUNCATED_IMAGES = False
+
 
 @pytest.mark.skipif(not is_win32(), reason="Windows only")
 class TestFileTiffW32:

src/PIL/ImageFile.py

@@ -28,6 +28,7 @@
 #
 
 import io
+import itertools
 import struct
 import sys
 
@@ -210,6 +211,13 @@ def load(self):
             except AttributeError:
                 prefix = b""
 
+            # Remove consecutive duplicates that only differ by their offset
+            self.tile = [
+                list(tiles)[-1]
+                for _, tiles in itertools.groupby(
+                    self.tile, lambda tile: (tile[0], tile[1], tile[3])
+                )
+            ]
             for decoder_name, extents, offset, args in self.tile:
                 decoder = Image._getdecoder(
                     self.mode, decoder_name, args, self.decoderconfig