Deprecate FILE_CHARSET setting

[Jon Dufresne]

The setting was introduced in ​953badbea5a04159adbfa970f5805c0232b6a401.

It looks as settings.FILE_CHARSET is no longer necessary and could easily be deprecated. Its existence is ​justified as:

But the common case is to read templates from the filesystem, and this creates a slight complication: not all filesystems store their data encoded as UTF-8. If your template files are not stored with a UTF-8 encoding, set the FILE_CHARSET setting to the encoding of the files on disk. When Django reads in a template file, it will convert the data from this encoding to Unicode.

Which seems suspect to me. I'm not aware of any modern environment that can't UTF-8 encode files to disk.

Its use is extremely limited in the code. After removal, we could instead document that files must be encoded using UTF-8.

Much like DEFAULT_CONTENT_TYPE, this setting doesn't play well with third-party libraries. If a project were to use this setting, it might be unable to load templates from third-party libraries that used the default UTF-8 encoding.

Further, this setting is entirely untested.

[Jon Dufresne]

​PR

Additionally, there was some discussion of this in ​PR#10428 which motivated this work.

[Carlton Gibson]

This would be nice. Django-developers thread asking for input: ​https://groups.google.com/d/topic/django-developers/7bZbYVV6hg4/discussion — lets see if there are any issues raised.

[Carlton Gibson]

Initial feedback on the thread is that this probably IS needed. I'm going to close as wontfix on that basis, but happy to reopen if the discussion develops there.

[Carlton Gibson]

So the discussion evolves such that it looks like the only issue here would be enforcing the use of UTF-8 in editors (for template files etc).

Is that something we want to do? (Not, as yet, answers on the thread re that.)

[Tim Graham <timograham@…>]

In 0cd465b:

Fixed #29817 -- Deprecated settings.FILE_CHARSET.

[Mariusz Felisiak <felisiak.mariusz@…>]

In 3d716467:

Refs #29817 -- Removed settings.FILE_CHARSET per deprecation timeline.