id summary reporter owner description type status component version severity resolution keywords cc stage has_patch needs_docs needs_tests needs_better_patch easy ui_ux 26743 DeserializationError local variable 'pk' referenced before assignment (which hides real error) Lakin Wecker nobody "The first error is this: {{{ Environment: Request Method: GET Request URL: http://localhost:8000/admin/artcollection/artobject/2298/history/734/ Django Version: 1.9.6 Python Version: 2.7.10 Installed Applications: ['saskartsboard.artcollection', 'saskartsboard.options', 'saskartsboard.descriptive_and_visual_dictionary', 'grappelli', 'versatileimagefield', 'select2', 'ckeditor', 'django.contrib.admin', 'django.contrib.auth', 'django.contrib.contenttypes', 'django.contrib.sessions', 'django.contrib.messages', 'django.contrib.staticfiles', 'reversion'] Installed Middleware: ['django.middleware.security.SecurityMiddleware', 'django.contrib.sessions.middleware.SessionMiddleware', 'django.middleware.common.CommonMiddleware', 'django.middleware.csrf.CsrfViewMiddleware', 'django.contrib.auth.middleware.AuthenticationMiddleware', 'django.contrib.auth.middleware.SessionAuthenticationMiddleware', 'django.contrib.messages.middleware.MessageMiddleware', 'django.middleware.clickjacking.XFrameOptionsMiddleware'] Traceback: File ""/media/mausoleum/Work/Development/saskartsboard-collections/env/local/lib/python2.7/site-packages/django/core/handlers/base.py"" in get_response 149. response = self.process_exception_by_middleware(e, request) File ""/media/mausoleum/Work/Development/saskartsboard-collections/env/local/lib/python2.7/site-packages/django/core/handlers/base.py"" in get_response 147. response = wrapped_callback(request, *callback_args, **callback_kwargs) File ""/media/mausoleum/Work/Development/saskartsboard-collections/env/local/lib/python2.7/site-packages/django/utils/decorators.py"" in _wrapped_view 149. response = view_func(request, *args, **kwargs) File ""/media/mausoleum/Work/Development/saskartsboard-collections/env/local/lib/python2.7/site-packages/django/views/decorators/cache.py"" in _wrapped_view_func 57. response = view_func(request, *args, **kwargs) File ""/media/mausoleum/Work/Development/saskartsboard-collections/env/local/lib/python2.7/site-packages/django/contrib/admin/sites.py"" in inner 244. return view(request, *args, **kwargs) File ""/media/mausoleum/Work/Development/saskartsboard-collections/env/local/lib/python2.7/site-packages/reversion/admin.py"" in revision_view 228. return self.revisionform_view(request, version, self.revision_form_template or self._get_template_list(""revision_form.html""), context) File ""/media/mausoleum/Work/Development/saskartsboard-collections/env/local/lib/python2.7/site-packages/reversion/admin.py"" in revisionform_view 191. version.revision.revert(delete=True) File ""/media/mausoleum/Work/Development/saskartsboard-collections/env/local/lib/python2.7/site-packages/reversion/models.py"" in revert 92. safe_revert(version_set) File ""/media/mausoleum/Work/Development/saskartsboard-collections/env/local/lib/python2.7/site-packages/reversion/models.py"" in safe_revert 31. version.revert() File ""/media/mausoleum/Work/Development/saskartsboard-collections/env/local/lib/python2.7/site-packages/reversion/models.py"" in revert 207. self.object_version.save() File ""/media/mausoleum/Work/Development/saskartsboard-collections/env/local/lib/python2.7/site-packages/reversion/models.py"" in object_version 168. return list(serializers.deserialize(self.format, data, ignorenonexistent=True))[0] File ""/media/mausoleum/Work/Development/saskartsboard-collections/env/local/lib/python2.7/site-packages/django/core/serializers/json.py"" in Deserializer 85. six.reraise(DeserializationError, DeserializationError(e), sys.exc_info()[2]) File ""/media/mausoleum/Work/Development/saskartsboard-collections/env/local/lib/python2.7/site-packages/django/core/serializers/json.py"" in Deserializer 79. for obj in PythonDeserializer(objects, **options): File ""/media/mausoleum/Work/Development/saskartsboard-collections/env/local/lib/python2.7/site-packages/django/core/serializers/python.py"" in Deserializer 142. raise base.DeserializationError.WithData(e, d['model'], d.get('pk'), pk) Exception Type: DeserializationError at /admin/artcollection/artobject/2298/history/734/ Exception Value: local variable 'pk' referenced before assignment }}} Which is caused by referring to the 'pk' variable on line 142, which is only set in the first iteration of the for loop on line 139. If you add a {{{raise}}} before line 142 you can see the real exception which is: {{{ Environment: Request Method: GET Request URL: http://localhost:8000/admin/artcollection/artobject/2298/history/734/ Django Version: 1.9.6 Python Version: 2.7.10 Installed Applications: ['saskartsboard.artcollection', 'saskartsboard.options', 'saskartsboard.descriptive_and_visual_dictionary', 'grappelli', 'versatileimagefield', 'select2', 'ckeditor', 'django.contrib.admin', 'django.contrib.auth', 'django.contrib.contenttypes', 'django.contrib.sessions', 'django.contrib.messages', 'django.contrib.staticfiles', 'reversion'] Installed Middleware: ['django.middleware.security.SecurityMiddleware', 'django.contrib.sessions.middleware.SessionMiddleware', 'django.middleware.common.CommonMiddleware', 'django.middleware.csrf.CsrfViewMiddleware', 'django.contrib.auth.middleware.AuthenticationMiddleware', 'django.contrib.auth.middleware.SessionAuthenticationMiddleware', 'django.contrib.messages.middleware.MessageMiddleware', 'django.middleware.clickjacking.XFrameOptionsMiddleware'] Traceback: File ""/media/mausoleum/Work/Development/saskartsboard-collections/env/local/lib/python2.7/site-packages/django/core/handlers/base.py"" in get_response 149. response = self.process_exception_by_middleware(e, request) File ""/media/mausoleum/Work/Development/saskartsboard-collections/env/local/lib/python2.7/site-packages/django/core/handlers/base.py"" in get_response 147. response = wrapped_callback(request, *callback_args, **callback_kwargs) File ""/media/mausoleum/Work/Development/saskartsboard-collections/env/local/lib/python2.7/site-packages/django/utils/decorators.py"" in _wrapped_view 149. response = view_func(request, *args, **kwargs) File ""/media/mausoleum/Work/Development/saskartsboard-collections/env/local/lib/python2.7/site-packages/django/views/decorators/cache.py"" in _wrapped_view_func 57. response = view_func(request, *args, **kwargs) File ""/media/mausoleum/Work/Development/saskartsboard-collections/env/local/lib/python2.7/site-packages/django/contrib/admin/sites.py"" in inner 244. return view(request, *args, **kwargs) File ""/media/mausoleum/Work/Development/saskartsboard-collections/env/local/lib/python2.7/site-packages/reversion/admin.py"" in revision_view 228. return self.revisionform_view(request, version, self.revision_form_template or self._get_template_list(""revision_form.html""), context) File ""/media/mausoleum/Work/Development/saskartsboard-collections/env/local/lib/python2.7/site-packages/reversion/admin.py"" in revisionform_view 191. version.revision.revert(delete=True) File ""/media/mausoleum/Work/Development/saskartsboard-collections/env/local/lib/python2.7/site-packages/reversion/models.py"" in revert 92. safe_revert(version_set) File ""/media/mausoleum/Work/Development/saskartsboard-collections/env/local/lib/python2.7/site-packages/reversion/models.py"" in safe_revert 31. version.revert() File ""/media/mausoleum/Work/Development/saskartsboard-collections/env/local/lib/python2.7/site-packages/reversion/models.py"" in revert 207. self.object_version.save() File ""/media/mausoleum/Work/Development/saskartsboard-collections/env/local/lib/python2.7/site-packages/reversion/models.py"" in object_version 168. return list(serializers.deserialize(self.format, data, ignorenonexistent=True))[0] File ""/media/mausoleum/Work/Development/saskartsboard-collections/env/local/lib/python2.7/site-packages/django/core/serializers/json.py"" in Deserializer 85. six.reraise(DeserializationError, DeserializationError(e), sys.exc_info()[2]) File ""/media/mausoleum/Work/Development/saskartsboard-collections/env/local/lib/python2.7/site-packages/django/core/serializers/json.py"" in Deserializer 79. for obj in PythonDeserializer(objects, **options): File ""/media/mausoleum/Work/Development/saskartsboard-collections/env/local/lib/python2.7/site-packages/django/core/serializers/python.py"" in Deserializer 139. for pk in field_value: Exception Type: DeserializationError at /admin/artcollection/artobject/2298/history/734/ Exception Value: 'NoneType' object is not iterable }}} Which is caused by not dealing with None values. I'm not exactly certain why the None value is set for this field value, but it is. My best guess at this point is that this field used to be a ForeignKey but has been migrated migrated into a ManyToMany and when the object was first saved, the FK was None, but now the ManyToMany is empty. If you believe this is an issue with django reversion, I will happily move it there, but I'm not so sure. Changing line 139 to: {{{ for pk in field_value or []: }}} Seems to get around the error." Bug closed Core (Serialization) 1.9 Normal fixed Accepted 1 0 0 0 0 0