fix deepcopy & pickle for unsaved model instances & empty image fields

stdimage/models.py

@@ -158,9 +158,9 @@ def __getstate__(self):
         state = super().__getstate__()
         state["variations"] = {}
         for variation_name in self.field.variations:
-            variation = getattr(self, variation_name)
-            variation_state = variation.__getstate__()
-            state["variations"][variation_name] = variation_state
+            if variation := getattr(self, variation_name, None):
+                variation_state = variation.__getstate__()
+                state["variations"][variation_name] = variation_state
         return state
 
     def __setstate__(self, state):
@@ -207,7 +207,7 @@ def __init__(
         render_variations=True,
         force_min_size=False,
         delete_orphans=False,
-        **kwargs
+        **kwargs,
     ):
         """
         Standardized ImageField for Django.

tests/test_models.py

@@ -174,6 +174,20 @@ def test_defer(self, db, django_assert_num_queries):
             deferred.image
         assert instance.image.thumbnail == deferred.image.thumbnail
 
+    @pytest.mark.django_db
+    def test_variations_deepcopy_unsaved(self):
+        instance_original = ResizeModel(image=self.fixtures["600x400.jpg"])
+        instance = deepcopy(instance_original)
+        assert isinstance(instance.image, StdImageFieldFile)
+        assert instance.image == instance_original.image
+
+    @pytest.mark.django_db
+    def test_variations_deepcopy_without_image(self):
+        instance_original = ThumbnailModel.objects.create(image=None)
+        instance = deepcopy(instance_original)
+        assert isinstance(instance.image, StdImageFieldFile)
+        assert instance.image == instance_original.image
+
     @pytest.mark.django_db
     def test_variations_deepcopy(self):
         """Tests test_variations() with a deep copied object"""