manage.py app commands enumeration fails silently when MEDIA_URL doesn't end with a slash

[peter.davis8@…]

When the MEDIA_URL setting in settings.py does not contain a forward slash at the end, calling manage.py without arguments will result in only django core commands being displayed, but no application commands (as specified in INSTALLED_APPS) are shown.

This is presumably due to the parsing of the settings.py file failing silently on the incorrect MEDIA_URL setting. Although it is explicitly called out within the settings.py file (within comments above the MEDIA_URL setting), having it fail loudly when running manage.py is potentially a more expected behaviour.

[Aymeric Augustin]

I can reproduce the problem and I think it's caused by:

        try:
            apps = settings.INSTALLED_APPS
        except ImproperlyConfigured:
            # Still useful for commands that do not require functional settings,
            # like startproject or help
            apps = []

in django.core.management.get_commands, as an invalid MEDIA_URL raises ImproperlyConfigured when the settings are first accessed.

[Claude Paroz]

Ouptut error message on sys.stderr if settings contain errors

[Julien Phalip]

That looks great to me! Just one nitpicky comment: it'd be useful to emphasize the causality between the two statements:

Project settings contain errors: <ERROR>
As a result, only the core Django commands are available.

[Claude Paroz <claude@…>]

In 40ca99097f34b2180b2afe6d0056cade4c732618:

Fixed #19724 -- Output error when settings are improperly configured

...during retrieval of available management commands.
Thanks Peter Davis for the report and Julien Phalip for the review.

[Claude Paroz <claude@…>]

In 2edef932ff4ffc766c7abe18bde2cc77babd8fef:

Revert "Fixed #19724 -- Output error when settings are improperly configured"

This reverts commit 40ca99097f34b2180b2afe6d0056cade4c732618.
Outputting error is not always suitable, for example this shouldn't
happen for the 'startproject' command.

[Claude Paroz]

The patch was not good.
For example, when running django-admin.py startproject, accessing settings.INSTALLED_APPS will always raise ImproperlyConfigured and this is the regular behaviour (no errors should be shown).

[Claude Paroz <claude@…>]

In a098bee1b9fa4df64f3fd72ff5cbae43bf27e539:

Fixed #19724 -- Output note when showing only core management commands

When listing available management commands, only core commands are
listed if settings have any error. This commit adds a note in this
case so errors are not totally silently skipped.
Thanks Peter Davis for the report.