AttributeError: NullTranslationsBabel instance has no attribute 'isactive' with Babel 1.3

[Jun Omae]

Reproduced accessing /about or /prefs/language page if installed Trac 1.0.1 and Babel 1.3 with no compiled catalogs. 0.12-stable has the same issue.

Traceback (most recent call last):
  File "/home/jun66j5/src/trac/edgewall/git/trac/web/main.py", line 497, in _dispatch_request
    dispatcher.dispatch(req)
  File "/home/jun66j5/src/trac/edgewall/git/trac/web/main.py", line 233, in dispatch
    content_type)
  File "/home/jun66j5/src/trac/edgewall/git/trac/web/chrome.py", line 976, in render_template
    data = self.populate_data(req, data)
  File "/home/jun66j5/src/trac/edgewall/git/trac/web/chrome.py", line 837, in populate_data
    'footer': Markup(footer and translation.gettext(footer))
  File "/home/jun66j5/src/trac/edgewall/git/trac/util/translation.py", line 195, in gettext
    if not self.isactive:
  File "/home/jun66j5/src/trac/edgewall/git/trac/util/translation.py", line 190, in __getattr__
    return getattr(self.active, name)
AttributeError: NullTranslationsBabel instance has no attribute 'isactive'

The issue is Translations.add() raises AttributeError: 'NullTranslations' object has no attribute 'add'.

After modified def isactive(self) with the following;

trac/util/translation.py

@@ -175 +175 @@
 
         @property
         def isactive(self):
-            if self._current.args is not None:
-                get_locale, env_path = self._current.args
-                self._current.args = None
-                self.activate(get_locale(), env_path)
-            # FIXME: The following always returns True: either a translation is
-            # active, or activation has failed.
-            return self._current.translations is not None \
-                   or self._activate_failed
+            try:
+                if self._current.args is not None:
+                    get_locale, env_path = self._current.args
+                    self._current.args = None
+                    self.activate(get_locale(), env_path)
+                # FIXME: The following always returns True: either a translation is
+                # active, or activation has failed.
+                return self._current.translations is not None \
+                       or self._activate_failed
+            except AttributeError, e:
+                import sys
+                exc_info = sys.exc_info()
+                raise Exception, unicode(e), exc_info[2]
 
         # Delegated methods
 

We can retrieve the following traceback.

2013-10-22 23:13:50,205 Trac[main] ERROR: Internal Server Error:
Traceback (most recent call last):
  File "/home/jun66j5/src/trac/edgewall/git/trac/web/main.py", line 497, in _dispatch_request
    dispatcher.dispatch(req)
  File "/home/jun66j5/src/trac/edgewall/git/trac/web/main.py", line 233, in dispatch
    content_type)
  File "/home/jun66j5/src/trac/edgewall/git/trac/web/chrome.py", line 976, in render_template
    data = self.populate_data(req, data)
  File "/home/jun66j5/src/trac/edgewall/git/trac/web/chrome.py", line 837, in populate_data
    'footer': Markup(footer and translation.gettext(footer))
  File "/home/jun66j5/src/trac/edgewall/git/trac/util/translation.py", line 199, in gettext
    if not self.isactive:
  File "/home/jun66j5/src/trac/edgewall/git/trac/util/translation.py", line 182, in isactive
    self.activate(get_locale(), env_path)
  File "/home/jun66j5/src/trac/edgewall/git/trac/util/translation.py", line 152, in activate
    t.add(Translations.load(locale_dir, locale or 'en_US',
Exception: 'NullTranslations' object has no attribute 'add'

But, if 1.0.2dev (r12205), reproduced only if Accept-Language header is missing or unsupported locale and 2 plugins with catalogs are installed.

Traceback (most recent call last):
  File "/home/jun66j5/src/trac/edgewall/git/trac/web/main.py", line 497, in _dispatch_request
    dispatcher.dispatch(req)
  File "/home/jun66j5/src/trac/edgewall/git/trac/web/main.py", line 233, in dispatch
    content_type)
  File "/home/jun66j5/src/trac/edgewall/git/trac/web/chrome.py", line 990, in render_template
    data = self.populate_data(req, data)
  File "/home/jun66j5/src/trac/edgewall/git/trac/web/chrome.py", line 851, in populate_data
    'footer': Markup(footer and translation.gettext(footer))
  File "/home/jun66j5/src/trac/edgewall/git/trac/util/translation.py", line 200, in gettext
    if not self.isactive:
  File "/home/jun66j5/src/trac/edgewall/git/trac/util/translation.py", line 182, in isactive
    self.activate(get_locale(), env_path)
  File "/home/jun66j5/src/trac/edgewall/git/trac/util/translation.py", line 159, in activate
    t.add(Translations.load(dirname, locale, domain))
  File "/home/jun66j5/venv/py26-babel1/lib/python2.6/site-packages/babel/support.py", line 571, in add
    existing.merge(translations)
Exception: 'NullTranslations' object has no attribute 'merge'

[Jun Omae]

0.12-stable has the same issue with Babel 1.0+.

Proposed fix for 0.12.6 can be found in log:jomae.git:ticket11345_0.12.6dev, for 1.0.2 in log:jomae.git:ticket11345.

[Jun Omae]

Committed in [12274] and merged in [12275,12276].