Special case the TEMPLATES setting, fixes #19

django_autoconfig/autoconfig.py

@@ -91,7 +91,7 @@ def apply_changes(self, settings):
 
         return changes
 
-def merge_dictionaries(current, new, only_defaults=False):
+def merge_dictionaries(current, new, only_defaults=False, template_special_case=False):
     '''
     Merge two settings dictionaries, recording how many changes were needed.
 
@@ -115,9 +115,20 @@ def merge_dictionaries(current, new, only_defaults=False):
         elif isinstance(current_value, (list, tuple)):
             for element in value:
                 if element not in current_value:
-                    current[key] = list(current_value) + [element]
-                    LOGGER.debug("Added %r to %r.", element, key)
-                    changes += 1
+                    if template_special_case and key == 'TEMPLATES':
+                        existing_matches = [
+                            template for template in current_value if template['BACKEND'] == element['BACKEND']
+                        ]
+                        if existing_matches:
+                            changes += merge_dictionaries(existing_matches[0], element)
+                        else:
+                            current[key] = list(current_value) + [element]
+                            LOGGER.debug("Added %r to %r.", element, key)
+                            changes += 1
+                    else:
+                        current[key] = list(current_value) + [element]
+                        LOGGER.debug("Added %r to %r.", element, key)
+                        changes += 1
         else:
             # If we don't know what to do with it, replace it.
             if current_value is not value:
@@ -154,6 +165,7 @@ def configure_settings(settings, environment_settings=True):
             changes += merge_dictionaries(
                 settings,
                 getattr(module, 'SETTINGS', {}),
+                template_special_case=True,
             )
             changes += merge_dictionaries(
                 settings,

django_autoconfig/tests/app_18templates1/autoconfig.py

@@ -0,0 +1,13 @@
+SETTINGS = {
+    'TEMPLATES': [
+        {
+            'BACKEND': 'django.template.backends.django.DjangoTemplates',
+            'APP_DIRS': True,
+            'OPTIONS': {
+                'context_processors': [
+                    'django.template.context_processors.request',
+                ],
+            },
+        },
+    ],
+}

django_autoconfig/tests/app_18templates2/autoconfig.py

@@ -0,0 +1,12 @@
+SETTINGS = {
+    'TEMPLATES': [
+        {
+            'BACKEND': 'django.template.backends.django.DjangoTemplates',
+            'OPTIONS': {
+                'context_processors': [
+                    'context.processor.2',
+                ],
+            },
+        },
+    ],
+}

django_autoconfig/tests/test_autoconfig.py

@@ -210,6 +210,31 @@ def test_environment_settings(self):
         )
         self.assertEqual(results, {'BLAH': 'test-value'})
 
+    def test_django18_templates(self):
+        '''
+        Check that the Django 1.8 TEMPLATES setting works.
+        '''
+        self.settings_dict['INSTALLED_APPS'] = [
+            'django_autoconfig.tests.app_18templates1',
+            'django_autoconfig.tests.app_18templates2',
+        ]
+        autoconfig.configure_settings(self.settings_dict)
+        self.assertEqual(
+            self.settings_dict['TEMPLATES'],
+            [
+                {
+                    'BACKEND': 'django.template.backends.django.DjangoTemplates',
+                    'APP_DIRS': True,
+                    'OPTIONS': {
+                        'context_processors': [
+                            'django.template.context_processors.request',
+                            'context.processor.2',
+                        ],
+                    },
+                },
+            ],
+        )
+
 
 class ConfigureUrlsTestCase(test.TestCase):
     '''Test the autoconfiguration of the urlconf.'''