Let Django users customize FORMAT_SETTINGS (a feature request)

[אורי]

I customized FORMAT_SETTINGS in Speedy Net, you can see more information in this commit:
​https://github.com/speedy-net/speedy-net/commit/f5dc4896c136a816ab9fe0dc360d3fd59d0a5f33  

And on Stack Overflow:
​https://stackoverflow.com/questions/57188435/django-how-do-i-override-default-date-formats-per-locale 

To customize FORMAT_SETTINGS I had to patch 14 files, because the tests failed and I had to patch the tests too. Is it possible to let Django users customize FORMAT_SETTINGS without having to patch files? For example you can check if the settings contain FORMAT_SETTINGS, and if it is - include these settings in the global FORMAT_SETTINGS (a union, like in the above commit).

formats.FORMAT_SETTINGS = formats.FORMAT_SETTINGS.union(django_settings.FORMAT_SETTINGS)

[אורי]

In django/utils/formats the FORMAT_SETTINGS is defined as a frozenset:
​https://github.com/django/django/blob/master/django/utils/formats.py#L31-L46

After this definition, you can add a code such as:

`

if ("FORMAT_SETTINGS" in settings):

FORMAT_SETTINGS = FORMAT_SETTINGS.union(settings.FORMAT_SETTINGS)

`

These 2 lines might do the job.

(I tried but I didn't find how to include code here as code).

[Carlton Gibson]

I see you created a DevelopersMailingList thread:

​https://groups.google.com/d/topic/django-developers/QabCOuVBa1o/discussion

That's good! Let's see if there's an agreement for the change there.
(As per my comment, I'm guessing you should be using ​Custom format files.)

I'll close this for now, but if there's agreement on the list we can re-open.