Misleading doc regarding language_code fallback

[pascal chambon]

The docs state that LANGUAGE_CODE will be used as fallback if a specific string has no translation in the active request language (​https://docs.djangoproject.com/en/1.7/ref/settings/#language-code).

However, my tests and my exploration of "real_trans.py" suggest that LANGUAGE_CODE is only used as a global fallback if the whole selected language is missing. Per-string fallback doesn't work it seems, on django <=1.7 at least (on current dev branch, lots of stuffs have moved in that code, so it seems a real fallback is getting implemented).

Example of a test output:

2015-03-18_14:48:34 UTC - INFO - <722724742146458> Language active for request: 'de' (LANGUAGE_CODE: 'fr-FR')

Translated string received : "'invalid input parameters'" (so no translation occurred)

When forcing active language to fr or fr-FR, the string is properly translated to "Paramètres invalides" in french.

Is that a bug of django, an error in the docs, or an error on my side ? I may provide a patch to fix django<=1.7 docs, if it occurs that per-string language fallback was actually never implemented yet.

[Claude Paroz]

You are right, this is fixed in Django 1.8/master. Documentation patch welcome.

[pascal chambon]

Attached is a patch for django <= 1.7,

regarding the patching of 1.8 docs, I don't know what the status is exactly (work in progress ? followed in another ticket ?), I guess the person(s) refactoring i18n will be best placed to update the doc, below is just a draft sample in case it helps.

.. versionchanged:: 1.8

  The ``LANGUAGE_CODE`` is now  also used to provide a fallback translation, 
  when no translation exists for a given literal in the user's preferred language.

[Tim Graham <timograham@…>]

In b2a80f9:

[1.7.x] Fixed #24503 -- Corrected docs on how LANGUAGE_CODE works as a fallback.

[Tim Graham]

Adding a patch for master/1.8 for Claude's review.

[Claude Paroz]

LGTM

[Tim Graham <timograham@…>]

In 8219eabb:

Fixed #24503 -- Added docs on LANGUAGE_CODE fallback change in 1.8.

Thanks Pakal and Claude.

[Tim Graham <timograham@…>]

In 5cd55140:

[1.8.x] Fixed #24503 -- Added docs on LANGUAGE_CODE fallback change in 1.8.

Thanks Pakal and Claude.

Backport of 8219eabbba6e8f6d8569792615935011b5cf0771 from master

[Claude Paroz <claude@…>]

In 1046c8af:

Fixed #24739 -- Documented translation fallback change

Refs #24503.

[Claude Paroz <claude@…>]

In 7915cbb:

[1.8.x] Fixed #24739 -- Documented translation fallback change

Refs #24503.
Backport of 1046c8afec from master.