Remove bilingual files removed from repository

[bugzilla-to-github]

This issue was created automatically by a script.

Bug 1345431

Bug Reporter: @mathjazz
CC: @TheoChevalier

Projects using bilingual file formats (xliff, po, lang...) can have different files exposed for each locale. If the file is added to the locale folder in repository, we detect it and enable it Pontoon. If it's removed, we also detect it, but don't remove it from Pontoon.

This doesn't happen often, but it still does:
mozilla-l10n/engagement-l10n@7bac95f

Implementations notes:
Files are represented with an instance of the TranslatedResource model. If an instance exist for the given locale, we expose the file in Pontoon. When a file is removed from the repository, we need to remove the TranslatedResource instance and aggregate denormalized stats for the corresponding Project, Locale and ProjectLocale instance.

Unlike changed_source_files(), changed_locales_files() ignores removed_files:
https://github.com/mozilla/pontoon/blob/master/pontoon/sync/vcs/models.py#L129

[bugzilla-to-github]

Comment Author: @mathjazz

*** Bug #1427767 has been marked as a duplicate of this bug. ***

[mathjazz]

Bumping priority, because the bug might hit us again soon after we stop using project configuration for "Foundation website - content".

[flodolo]

@mathjazz
Is it expected to have a P1 issue open for so long?

[mathjazz]

No. :)

This should be taken care of as part of the "Improve Pontoon sync reliability" OKR.

Also, P1 was probably to high priority in first place.