Ticket #16938: 16938.empty-string-locale-format.diff

django/utils/formats.py

@@ -71 +71 @@
             lang = get_language()
         cache_key = (format_type, lang)
         try:
-            return _format_cache[cache_key] or getattr(settings, format_type)
+            cached = _format_cache[cache_key]
+            if cached is not None:
+                return cached
+            else:
+                # Return the general setting by default
+                return getattr(settings, format_type)
         except KeyError:
             for module in get_format_modules(lang):
                 try:

tests/regressiontests/i18n/tests.py

@@ -14 +14 @@
 from django.test.utils import override_settings
 from django.utils import translation
 from django.utils.formats import (get_format, date_format, time_format,
-    localize, localize_input, iter_format_modules, get_format_modules)
+    localize, localize_input, iter_format_modules, get_format_modules,
+    number_format)
 from django.utils.importlib import import_module
 from django.utils.numberformat import format as nformat
 from django.utils.safestring import mark_safe, SafeString, SafeUnicode
@@ -397 +398 @@
                 self.assertEqual(u'66666.67', Template('{{ n|floatformat:2 }}').render(self.ctxt))
                 self.assertEqual(u'100000.0', Template('{{ f|floatformat }}').render(self.ctxt))
 
+    def test_empty_string_format(self):
+        """
+        Ensure that the active locale's formats take precedence over the
+        default settings even if they are empty strings.
+        Refs #16938.
+        """
+        from django.conf.locale.fr import formats as fr_formats
+        backup = fr_formats.THOUSAND_SEPARATOR
+        fr_formats.THOUSAND_SEPARATOR = ''
+        with self.settings(USE_L10N = True, USE_THOUSAND_SEPARATOR=True,
+                           THOUSAND_SEPARATOR='!'):
+            with translation.override('fr'):
+                self.assertEqual(number_format(999999), '999999')
+                # Even a second time (after the format has been cached)...
+                self.assertEqual(number_format(999999), '999999')
+        fr_formats.THOUSAND_SEPARATOR = backup
+
     def test_l10n_enabled(self):
         settings.USE_L10N = True
         # Catalan locale