app registry error when running startproject with a template containing DATE_FORMAT

[jarshwah]

Repro:

django-admin startproject --template=template/ fail

Where template/project.py contains:

{% now "DATE_FORMAT" %}

And the traceback:

Traceback (most recent call last):
  File "/usr/local/bin/django-admin", line 9, in <module>
    load_entry_point('Django==1.7b4', 'console_scripts', 'django-admin')()
  File "/usr/local/lib/python3.4/site-packages/django/core/management/__init__.py", line 427, in execute_from_command_line
    utility.execute()
  File "/usr/local/lib/python3.4/site-packages/django/core/management/__init__.py", line 419, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/usr/local/lib/python3.4/site-packages/django/core/management/base.py", line 288, in run_from_argv
    self.execute(*args, **options.__dict__)
  File "/usr/local/lib/python3.4/site-packages/django/core/management/base.py", line 337, in execute
    output = self.handle(*args, **options)
  File "/usr/local/lib/python3.4/site-packages/django/core/management/commands/startproject.py", line 31, in handle
    super(Command, self).handle('project', project_name, target, **options)
  File "/usr/local/lib/python3.4/site-packages/django/core/management/templates.py", line 158, in handle
    content = template.render(context)
  File "/usr/local/lib/python3.4/site-packages/django/template/base.py", line 148, in render
    return self._render(context)
  File "/usr/local/lib/python3.4/site-packages/django/template/base.py", line 142, in _render
    return self.nodelist.render(context)
  File "/usr/local/lib/python3.4/site-packages/django/template/base.py", line 844, in render
    bit = self.render_node(node, context)
  File "/usr/local/lib/python3.4/site-packages/django/template/base.py", line 858, in render_node
    return node.render(context)
  File "/usr/local/lib/python3.4/site-packages/django/template/defaulttags.py", line 393, in render
    return date(datetime.now(tz=tzinfo), self.format_string)
  File "/usr/local/lib/python3.4/site-packages/django/template/defaultfilters.py", line 766, in date
    return formats.date_format(value, arg)
  File "/usr/local/lib/python3.4/site-packages/django/utils/formats.py", line 126, in date_format
    return dateformat.format(value, get_format(format or 'DATE_FORMAT', use_l10n=use_l10n))
  File "/usr/local/lib/python3.4/site-packages/django/utils/dateformat.py", line 343, in format
    return df.format(format_string)
  File "/usr/local/lib/python3.4/site-packages/django/utils/dateformat.py", line 35, in format
    pieces.append(force_text(getattr(self, piece)()))
  File "/usr/local/lib/python3.4/site-packages/django/utils/encoding.py", line 83, in force_text
    s = six.text_type(s)
  File "/usr/local/lib/python3.4/site-packages/django/utils/functional.py", line 144, in __text_cast
    return func(*self.__args, **self.__kw)
  File "/usr/local/lib/python3.4/site-packages/django/utils/translation/__init__.py", line 91, in pgettext
    return _trans.pgettext(context, message)
  File "/usr/local/lib/python3.4/site-packages/django/utils/translation/trans_real.py", line 322, in pgettext
    result = ugettext(msg_with_ctxt)
  File "/usr/local/lib/python3.4/site-packages/django/utils/translation/trans_real.py", line 311, in gettext
    return do_translate(message, 'gettext')
  File "/usr/local/lib/python3.4/site-packages/django/utils/translation/trans_real.py", line 298, in do_translate
    _default = translation(settings.LANGUAGE_CODE)
  File "/usr/local/lib/python3.4/site-packages/django/utils/translation/trans_real.py", line 201, in translation
    default_translation = _fetch(settings.LANGUAGE_CODE)
  File "/usr/local/lib/python3.4/site-packages/django/utils/translation/trans_real.py", line 184, in _fetch
    for app_config in reversed(list(apps.get_app_configs())):
  File "/usr/local/lib/python3.4/site-packages/django/apps/registry.py", line 125, in get_app_configs
    self.check_ready()
  File "/usr/local/lib/python3.4/site-packages/django/apps/registry.py", line 119, in check_ready
    raise RuntimeError("App registry isn't ready yet.")
RuntimeError: App registry isn't ready yet.

Sample template attached.

[Claude Paroz]

DATE_FORMAT contains language-dependent elements, hence the failure because the translation infrastructure cannot be used without configured settings (which startproject cannot obviously provide).

One possible fix would be to deactivate translations when the management command infrastructure detects settings are not available:

diff --git a/django/core/management/__init__.py b/django/core/management/__init__.py
index df21ed9..8d8a4ef 100644
--- a/django/core/management/__init__.py
+++ b/django/core/management/__init__.py
@@ -388,7 +388,10 @@ class ManagementUtility(object):
             settings.INSTALLED_APPS
         except ImproperlyConfigured:
             # Some commands are supposed to work without configured settings
-            pass
+            # Still, let's deactivate translations
+            from django.utils import translation
+            from django.utils.translation import trans_null
+            translation._trans = trans_null
         else:
             django.setup()

[Aymeric Augustin]

What about configuring Django with the default settings (from global_settings.py) when no settings module is available?

[Claude Paroz]

Very interesting idea, indeed. That would give:

diff --git a/django/core/management/__init__.py b/django/core/management/__init__.py
index df21ed9..00c1a1f 100644
--- a/django/core/management/__init__.py
+++ b/django/core/management/__init__.py
@@ -388,9 +388,10 @@ class ManagementUtility(object):
             settings.INSTALLED_APPS
         except ImproperlyConfigured:
             # Some commands are supposed to work without configured settings
-            pass
-        else:
-            django.setup()
+            # Use default settings instead
+            settings.configure()
+
+        django.setup()
 
         self.autocomplete()

[jarshwah]

When I raised the bug I imagined the fix would look something like above (enabling default settings and calling setup()). If there are other lingering bugs that involve configuring django that does not use translations, you'd be in trouble with the first patch that only disables translations.

[Aymeric Augustin]

Claude, that's the kind of change I imagined. I'll have a bit more time to think about it and commit it tomorrow. Thanks for your help.

[Aymeric Augustin]

PR: ​https://github.com/django/django/pull/2722

What do you think of this refactoring?

[Aymeric Augustin <aymeric.augustin@…>]

In 4865326f2200aa1c480526feef5428cf780ab3c6:

Fixed #22699 -- Configure default settings in some management commands.

This makes it possible to run django.setup() in management commands that
don't need a settings module. In addition it simplifies error handling.

Thanks Claude for the review.

[Aymeric Augustin <aymeric.augustin@…>]

In 430faebe3baa3daecc0ea083c1259c2b43b0557f:

[1.7.x] Fixed #22699 -- Configure default settings in some management commands.

This makes it possible to run django.setup() in management commands that
don't need a settings module. In addition it simplifies error handling.

Thanks Claude for the review.

Backport of 4865326f from master.