[1.11.x] Fixed #28242 -- Moved ImageField file extension validation to the form field.

Backport of a0c07d77fc from master

django/db/models/fields/files.py

@@ -8,7 +8,6 @@ from django.core import checks
 from django.core.files.base import File
 from django.core.files.images import ImageFile
 from django.core.files.storage import default_storage
-from django.core.validators import validate_image_file_extension
 from django.db.models import signals
 from django.db.models.fields import Field
 from django.utils import six
@@ -387,7 +386,6 @@ class ImageFieldFile(ImageFile, FieldFile):
 
 
 class ImageField(FileField):
-    default_validators = [validate_image_file_extension]
     attr_class = ImageFieldFile
     descriptor_class = ImageFileDescriptor
     description = _("Image")

django/forms/fields.py

@@ -610,6 +610,7 @@ class FileField(Field):
 
 
 class ImageField(FileField):
+    default_validators = [validators.validate_image_file_extension]
     default_error_messages = {
         'invalid_image': _(
             "Upload a valid image. The file you uploaded was either not an "

docs/releases/1.11.2.txt

@@ -58,3 +58,7 @@ Bugfixes
 
 * Fixed a regression where ``file_move_safe()`` crashed when moving files to a
   CIFS mount (:ticket:`28170`).
+
+* Moved the ``ImageField`` file extension validation added in Django 1.11 from
+  the model field to the form field to reallow the use case of storing images
+  without an extension (:ticket:`28242`).

docs/releases/1.11.txt

@@ -327,6 +327,7 @@ Models
 
 * :class:`~django.db.models.ImageField` now has a default
   :data:`~django.core.validators.validate_image_file_extension` validator.
+  (This validator moved to the form field in :doc:`Django 1.11.2 <1.11.2>`.)
 
 * Added support for time truncation to
   :class:`~django.db.models.functions.datetime.Trunc` functions.

tests/forms_tests/field_tests/test_imagefield.py

@@ -4,7 +4,7 @@ import os
 import unittest
 
 from django.core.files.uploadedfile import SimpleUploadedFile
-from django.forms import ImageField
+from django.forms import ImageField, ValidationError
 from django.test import SimpleTestCase
 from django.utils._os import upath
 
@@ -58,3 +58,12 @@ class ImageFieldTest(SimpleTestCase):
             self.assertIsNone(uploaded_file.content_type)
         finally:
             Image.register_mime(BmpImageFile.format, 'image/bmp')
+
+    def test_file_extension_validation(self):
+        f = ImageField()
+        img_path = get_img_path('filepath_test_files/1x1.png')
+        with open(img_path, 'rb') as img_file:
+            img_data = img_file.read()
+        img_file = SimpleUploadedFile('1x1.txt', img_data)
+        with self.assertRaisesMessage(ValidationError, "File extension 'txt' is not allowed."):
+            f.clean(img_file)

tests/model_fields/test_imagefield.py

@@ -4,7 +4,7 @@ import os
 import shutil
 from unittest import skipIf
 
-from django.core.exceptions import ImproperlyConfigured, ValidationError
+from django.core.exceptions import ImproperlyConfigured
 from django.core.files import File
 from django.core.files.images import ImageFile
 from django.test import TestCase
@@ -133,12 +133,6 @@ class ImageFieldTests(ImageFieldTestMixin, TestCase):
         self.assertEqual(hash(p1_db.mugshot), hash(p1.mugshot))
         self.assertIs(p1_db.mugshot != p1.mugshot, False)
 
-    def test_validation(self):
-        p = self.PersonModel(name="Joan")
-        p.mugshot.save("shot.txt", self.file1)
-        with self.assertRaisesMessage(ValidationError, "File extension 'txt' is not allowed."):
-            p.full_clean()
-
     def test_instantiate_missing(self):
         """
         If the underlying file is unavailable, still create instantiate the

tests/model_forms/models.py

@@ -214,6 +214,17 @@ try:
 
         def __str__(self):
             return self.description
+
+    class NoExtensionImageFile(models.Model):
+        def upload_to(self, filename):
+            return 'tests/no_extension'
+
+        description = models.CharField(max_length=20)
+        image = models.ImageField(storage=temp_storage, upload_to=upload_to)
+
+        def __str__(self):
+            return self.description
+
 except ImportError:
     test_images = False
 

tests/model_forms/tests.py

@@ -36,7 +36,7 @@ from .models import (
 )
 
 if test_images:
-    from .models import ImageFile, OptionalImageFile
+    from .models import ImageFile, OptionalImageFile, NoExtensionImageFile
 
     class ImageFileForm(forms.ModelForm):
         class Meta:
@@ -48,6 +48,11 @@ if test_images:
             model = OptionalImageFile
             fields = '__all__'
 
+    class NoExtensionImageFileForm(forms.ModelForm):
+        class Meta:
+            model = NoExtensionImageFile
+            fields = '__all__'
+
 
 class ProductForm(forms.ModelForm):
     class Meta:
@@ -2469,6 +2474,19 @@ class FileAndImageFieldTests(TestCase):
         self.assertEqual(instance.image.name, 'foo/test4.png')
         instance.delete()
 
+        # Editing an instance that has an image without an extension shouldn't
+        # fail validation. First create:
+        f = NoExtensionImageFileForm(
+            data={'description': 'An image'},
+            files={'image': SimpleUploadedFile('test.png', image_data)},
+        )
+        self.assertTrue(f.is_valid())
+        instance = f.save()
+        self.assertEqual(instance.image.name, 'tests/no_extension')
+        # Then edit:
+        f = NoExtensionImageFileForm(data={'description': 'Edited image'}, instance=instance)
+        self.assertTrue(f.is_valid())
+
 
 class ModelOtherFieldTests(SimpleTestCase):
     def test_big_integer_field(self):