Ticket #13750: 13750_test_simple_solution.diff

django/db/models/fields/files.py

@@ -220 +220 @@
             file.field = self.field
             file.storage = self.field.storage
 
+        # Saving a file-like object closes the IO stream. When getting an Image
+        # we want to return an open file instead of a closed one
+        if isinstance(file, ImageFieldFile) and hasattr(file, 'field'):
+            # Check that there is actually a file attached to the ImageFieldFile object
+            if file._file:
+                file.open()
+
         # That was fun, wasn't it?
         return instance.__dict__[self.field.name]
 

tests/model_fields/models.py

@@ -384 +384 @@
 
     class Meta:
         abstract = True
+
+
+class Profile(models.Model):
+    image = models.ImageField()

tests/model_fields/test_imagefield.py

@@ -181 +181 @@
         loaded_p = pickle.loads(dump)
         self.assertEqual(p.mugshot, loaded_p.mugshot)
 
+    def test_image_field_io_closed_file(self):
+        """
+        Opening 'image' property as Image object of a model's ImageField will fail
+        with an 'I/O operation on closed file' error. Regression for #13750
+        """
+        from .models import Profile
+        profile = Profile()
+        profile.image = self.file1
+
+        profile.save()
+
+        w = profile.image.width
+        h = profile.image.height
+
+        original = Image.open(profile.image)
+
 
 @skipIf(Image is None, "Pillow is required to test ImageField")
 class ImageFieldTwoDimensionsTests(ImageFieldTestMixin, TestCase):