Ticket #8033: better_error_handling_for_ugettext_r8377.diff

django/db/models/loading.py

@@ -9 +9 @@
 import threading
 
 __all__ = ('get_apps', 'get_app', 'get_models', 'get_model', 'register_models',
-        'load_app', 'app_cache_ready')
+        'load_app', 'app_cache_ready', 'app_cache_loading')
 
 class AppCache(object):
     """
@@ -30 +30 @@
 
         # -- Everything below here is only used when populating the cache --
         loaded = False,
+        loading = False,
         handled = {},
         postponed = [],
         nesting_level = 0,
@@ -51 +52 @@
         try:
             if self.loaded:
                 return
+            self.loading = True
             for app_name in settings.INSTALLED_APPS:
                 if app_name in self.handled:
                     continue
@@ -59 +61 @@
                 for app_name in self.postponed:
                     self.load_app(app_name)
                 self.loaded = True
+                self.loading = False
         finally:
             self.write_lock.release()
 
@@ -92 +95 @@
         """
         return self.loaded
 
+    def app_cache_loading(self):
+        """
+        Returns true if the model cache is now loading.
+        """
+        return self.loading
+
+
     def get_apps(self):
         "Returns a list of all installed modules that contain models."
         self._populate()
@@ -187 +197 @@
 register_models = cache.register_models
 load_app = cache.load_app
 app_cache_ready = cache.app_cache_ready
+app_cache_loading = cache.app_cache_loading

django/core/exceptions.py

@@ -28 +28 @@
     "Django is somehow improperly configured"
     pass
 
+class ImproperlyImplemented(Exception):
+    "Django is somehow improperly implemented"
+    pass
+
 class FieldError(Exception):
     """Some kind of problem with a model field."""
     pass

django/views/debug.py

@@ -60 +60 @@
 
     def get_traceback_html(self):
         "Return HTML code for traceback."
+        from django.utils import translation
+        translation.deactivate_all() # avoid possible translation errors in 500 error handling
 
         if issubclass(self.exc_type, TemplateDoesNotExist):
             from django.template.loader import template_source_loaders

django/utils/translation/trans_real.py

@@ -7 +7 @@
 import gettext as gettext_module
 from cStringIO import StringIO
 
+from django.core.exceptions import ImproperlyImplemented
+from django.db.models.loading import app_cache_loading, get_apps
 from django.utils.safestring import mark_safe, SafeData
 from django.utils.thread_support import currentThread
 
@@ -270 +272 @@
     """
     global _default, _active
     t = _active.get(currentThread(), None)
+    if app_cache_loading() and \
+       not isinstance(t, gettext_module.NullTranslations):
+        raise ImproperlyImplemented(
+            "django.utils.translation.%(func_name)s function called for "
+            "translation of '%(message)s' when Django apps is still loading."
+            "%(func_name)s function must be called after "
+            "applications loading." % {'func_name': translation_function,
+                                       'message': message})
     if t is not None:
         result = getattr(t, translation_function)(message)
     else: