Fixed #35139 -- Prevented file read after ImageField is saved to storage.

3 files changed, 50 insertions, 1 deletions

diff --git a/tests/model_fields/models.py b/tests/model_fields/models.py
index e34f3c8947..18a6fdbc1c 100644
--- a/tests/model_fields/models.py
+++ b/tests/model_fields/models.py
@@ -13,6 +13,8 @@ from django.db.models.functions import Lower
 from django.utils.functional import SimpleLazyObject
 from django.utils.translation import gettext_lazy as _
 
+from .storage import NoReadFileSystemStorage
+
 try:
     from PIL import Image
 except ImportError:
@@ -373,6 +375,21 @@ if Image:
             width_field="headshot_width",
         )
 
+    class PersonNoReadImage(models.Model):
+        """
+        Model that defines an ImageField with a storage backend that does not
+        support reading.
+        """
+
+        mugshot = models.ImageField(
+            upload_to="tests",
+            storage=NoReadFileSystemStorage(),
+            width_field="mugshot_width",
+            height_field="mugshot_height",
+        )
+        mugshot_width = models.IntegerField()
+        mugshot_height = models.IntegerField()
+
 
 class CustomJSONDecoder(json.JSONDecoder):
     def __init__(self, object_hook=None, *args, **kwargs):
diff --git a/tests/model_fields/storage.py b/tests/model_fields/storage.py
new file mode 100644
index 0000000000..9002c12683
--- /dev/null
+++ b/tests/model_fields/storage.py
@@ -0,0 +1,6 @@
+from django.core.files.storage.filesystem import FileSystemStorage
+
+
+class NoReadFileSystemStorage(FileSystemStorage):
+    def open(self, *args, **kwargs):
+        raise AssertionError("This storage class does not support reading.")
diff --git a/tests/model_fields/test_imagefield.py b/tests/model_fields/test_imagefield.py
index 8c93ed1bdb..7265da598b 100644
--- a/tests/model_fields/test_imagefield.py
+++ b/tests/model_fields/test_imagefield.py
@@ -18,6 +18,7 @@ if Image:
     from .models import (
         Person,
         PersonDimensionsFirst,
+        PersonNoReadImage,
         PersonTwoImages,
         PersonWithHeight,
         PersonWithHeightAndWidth,
@@ -30,7 +31,7 @@ else:
         pass
 
     PersonWithHeight = PersonWithHeightAndWidth = PersonDimensionsFirst = Person
-    PersonTwoImages = Person
+    PersonTwoImages = PersonNoReadImage = Person
 
 
 class ImageFieldTestMixin(SerializeMixin):
@@ -469,3 +470,28 @@ class TwoImageFieldTests(ImageFieldTestMixin, TestCase):
         # Dimensions were recalculated, and hence file should have opened.
         self.assertIs(p.mugshot.was_opened, True)
         self.assertIs(p.headshot.was_opened, True)
+
+
+@skipIf(Image is None, "Pillow is required to test ImageField")
+class NoReadTests(ImageFieldTestMixin, TestCase):
+    def test_width_height_correct_name_mangling_correct(self):
+        instance1 = PersonNoReadImage()
+
+        instance1.mugshot.save("mug", self.file1)
+
+        self.assertEqual(instance1.mugshot_width, 4)
+        self.assertEqual(instance1.mugshot_height, 8)
+
+        instance1.save()
+
+        self.assertEqual(instance1.mugshot_width, 4)
+        self.assertEqual(instance1.mugshot_height, 8)
+
+        instance2 = PersonNoReadImage()
+        instance2.mugshot.save("mug", self.file1)
+        instance2.save()
+
+        self.assertNotEqual(instance1.mugshot.name, instance2.mugshot.name)
+
+        self.assertEqual(instance1.mugshot_width, instance2.mugshot_width)
+        self.assertEqual(instance1.mugshot_height, instance2.mugshot_height)