manage.py sqlcustom fails if models are in a submodule

[David Rogers]

This is similar to #6961, from what I've seen. According to ​the docs for 1.2:

Django provides a hook for passing the database arbitrary SQL that's executed just after the CREATE TABLE 
statements when you run syncdb. You can use this hook to populate default records, or you could also create
SQL functions, views, triggers, etc.

The hook is simple: Django just looks for a file called sql/<modelname>.sql, in your app directory, where 
<modelname> is the model's name in lowercase.

This doesn't work when the "models" module is a directory instead of a file, i.e. project/application/models/ vice project/application/models.py. Apparently, sqlcustom is using similar logic to what was described in #6961, since I can move my sql/ directory into the models/ directory - a la project/application/models/sql/ - and everything works.

[Fede Heinz]

Fixes the bug, adds tests

[Fede Heinz]

The attached patch fixes the bug, and adds tests to check that both cases (models module is a directory or a file) work.

[Ramiro Morales]

Reopening. The fixed status is set when a commit lands in the code repository.

[Julien Phalip]

Unittests are now preferred over doctests in the django codebase. Could you rewrite your tests accordingly? Thanks!

[Aymeric Augustin]

Change UI/UX from NULL to False.

[Aymeric Augustin]

Change Easy pickings from NULL to False.

[Claude Paroz]

#19338 and #19358 are duplicates.

[Tim Graham]

​https://github.com/django/django/pull/1359

[Tim Graham]

Also reported in #15519 the ​PR there addresses backwards incompatibility by searching both app/sql and app/models/sql with a DeprecationWarning if the latter is used. I'm not a huge fan of adding extra code and tests to support that for a release or two, but I'll do it if necessary.

[Vlastimil Zíma]

Replying to timo:

Also reported in #15519 the ​PR there addresses backwards incompatibility by searching both app/sql and app/models/sql with a DeprecationWarning if the latter is used. I'm not a huge fan of adding extra code and tests to support that for a release or two, but I'll do it if necessary.

In #15519:comment:2 jacob required to use both locations. My patch also contains a test. The patch does not apply, because of all the changes in tests, but it should be easy to fix.

[Tim Graham <timograham@…>]

In 31c13a99bb9ebdaf12ccab4e880c5da930d86e79:

Fixed #14300 -- Fixed initial SQL location if models is a package.

Thanks al_the_x for the report and fheinz for the draft patch.