Fixed #19457 -- ImageField size detection failed for some files.

This was caused by PIL raising a zlib truncated stream error since we fed
the parser with chunks instead of the whole image.

1 files changed, 13 insertions, 1 deletions

diff --git a/django/core/files/images.py b/django/core/files/images.py
index 7d7eac65db..a8d3d8018b 100644
--- a/django/core/files/images.py
+++ b/django/core/files/images.py
@@ -4,7 +4,11 @@ Utility functions for handling images.
 Requires PIL, as you might imagine.
 """
 
+import zlib
+import sys
+
 from django.core.files import File
+from django.utils import six
 
 class ImageFile(File):
     """
@@ -55,7 +59,15 @@ def get_image_dimensions(file_or_path, close=False):
             data = file.read(chunk_size)
             if not data:
                 break
-            p.feed(data)
+            try:
+                p.feed(data)
+            except zlib.error as e:
+                # ignore zlib complaining on truncated stream, just feed more
+                # data to parser (ticket #19457).
+                if e.message.startswith("Error -5"):
+                    pass
+                else:
+                    six.reraise(*sys.exc_info())
             if p.image:
                 return p.image.size
             chunk_size = chunk_size*2