Context manager for temporarily switching fallbacks on or off.

modeltranslation/fields.py

@@ -156,7 +156,7 @@ class TranslationFieldDescriptor(object):
             # Here we check only for None and '', because e.g. 0 should not fall back.
             if val is not None and val != '':
                 return val
-        if self.fallback_value is None:
+        if self.fallback_value is None or not mt_settings.ENABLE_FALLBACKS:
             return self.field.get_default()
         else:
             return self.fallback_value

modeltranslation/settings.py

@@ -51,3 +51,4 @@ for key, value in FALLBACK_LANGUAGES.iteritems():
         if lang not in AVAILABLE_LANGUAGES:
             raise ImproperlyConfigured(
                 'MODELTRANSLATION_FALLBACK_LANGUAGES: "%s" not in LANGUAGES setting.' % lang)
+ENABLE_FALLBACKS = getattr(settings, 'MODELTRANSLATION_ENABLE_FALLBACKS', True)

modeltranslation/utils.py

@@ -90,6 +90,8 @@ def resolution_order(lang, override=None):
     First is always the parameter language, later are fallback languages.
     Override parameter has priority over FALLBACK_LANGUAGES.
     """
+    if not settings.ENABLE_FALLBACKS:
+        return (lang,)
     if override is None:
         override = {}
     fallback_for_lang = override.get(lang, settings.FALLBACK_LANGUAGES.get(lang, ()))
@@ -123,3 +125,25 @@ def auto_populate(mode='all'):
         yield
     finally:
         settings.AUTO_POPULATE = current_population_mode
+
+
+@contextmanager
+def fallbacks(enable=True):
+    """
+    Temporarily switch all language fallbacks on or off.
+
+    Example:
+
+        with fallbacks(False):
+            lang_has_slug = bool(self.slug)
+
+    May be used to enable fallbacks just when they're needed saving on some
+    processing or check if there is a value for the current language (not
+    knowing the language)
+    """
+    current_enable_fallbacks = settings.ENABLE_FALLBACKS
+    settings.ENABLE_FALLBACKS = enable
+    try:
+        yield
+    finally:
+        settings.ENABLE_FALLBACKS = current_enable_fallbacks