Convert the anchor kwarg from SafeString to str.

imagekit/templatetags/imagekit.py

@@ -92,6 +92,11 @@ def render(self, context):
         kwargs = {k: v.resolve(context) for k, v in self._generator_kwargs.items()}
         kwargs['source'] = self._source.resolve(context)
         kwargs.update(parse_dimensions(self._dimensions.resolve(context)))
+        if kwargs.get('anchor'):
+            # ImageKit uses pickle at protocol 0, which throws infinite
+            # recursion errors when anchor is set to a SafeString instance.
+            # This converts the SafeString into a str instance.
+            kwargs['anchor'] = kwargs['anchor'][:]
         generator = generator_registry.get(generator_id, **kwargs)
 
         context[variable_name] = ImageCacheFile(generator)
@@ -114,6 +119,11 @@ def render(self, context):
         kwargs = {k: v.resolve(context) for k, v in self._generator_kwargs.items()}
         kwargs['source'] = self._source.resolve(context)
         kwargs.update(dimensions)
+        if kwargs.get('anchor'):
+            # ImageKit uses pickle at protocol 0, which throws infinite
+            # recursion errors when anchor is set to a SafeString instance.
+            # This converts the SafeString into a str instance.
+            kwargs['anchor'] = kwargs['anchor'][:]
         generator = generator_registry.get(generator_id, **kwargs)
 
         file = ImageCacheFile(generator)

tests/test_thumbnail_tag.py

@@ -15,6 +15,16 @@ def test_img_tag():
         assert attrs[k].strip() != ''
 
 
+def test_img_tag_anchor():
+    ttag = r"""{% thumbnail '100x100' img anchor='c' %}"""
+    clear_imagekit_cache()
+    attrs = get_html_attrs(ttag)
+    expected_attrs = {'src', 'width', 'height'}
+    assert set(attrs.keys()) == expected_attrs
+    for k in expected_attrs:
+        assert attrs[k].strip() != ''
+
+
 def test_img_tag_attrs():
     ttag = r"""{% thumbnail '100x100' img -- alt="Hello" %}"""
     clear_imagekit_cache()
@@ -58,6 +68,13 @@ def test_assignment_tag():
     assert html != ''
 
 
+def test_assignment_tag_anchor():
+    ttag = r"""{% thumbnail '100x100' img anchor='c' as th %}{{ th.url }}"""
+    clear_imagekit_cache()
+    html = render_tag(ttag)
+    assert html != ''
+
+
 def test_single_dimension():
     ttag = r"""{% thumbnail '100x' img as th %}{{ th.width }}"""
     clear_imagekit_cache()