The problem

Date format localization is currently handled by the system module, which provides its own UI not consistent with the rest of the localization system and requires features -config translation- provided by locale module. This causes multiple issues ranging from usability to some ugly workarounds to update localized formats, to hidden functional dependencies (and maybe the feature being in the wrong module).

Proposed solution

- Move Date format localization to locale module (#2059835: Implement translation interface for date formats as part of locale UI)
- Use the right API, aka config translation, to update and handle date format localization.
- Integrate the UI with Regional and Language / User Interface translation.
- Make it consistent with interface translation respecting locale settings like 'translate english'.

Related issues

While there are multiple related issues, none of them is trying to address the problem as a whole, but just a few symptoms/sides of it.
The main patch, that needs review and UI discussion, #2059835: Implement translation interface for date formats as part of locale UI
#2003892: Convert date formats to config entities
#2003802: Under Configuration => regional and language, merge Regional settings and date and time formats
#987534: Default installed vocabulary name, tags, date types, block region names, timezone locations, tabs and menus not translatable
#2015021: Update configuration schema of system date formats
#1966538: Translation is not updated for configuration, when the config changes
#1267520: Improve date and time localization user experience
#2098089: Date formats cannot be translated (the core UIs are useless)
#2100351: Date format name 'custom' is reserved but not checked for

Remaining Tasks

  • click through the UI and figure out the features, a full UI / feature comparison of D7 and D8, so we know what regressed in fact.

Comments

The purpose of the date formats to languages feature is to assign languages to different date formats. It does not actually make it possible to assign different date formats for different languages I believe. I don't fully grasp how it uses the language overrides and if so why it stores language copies that may be the same. I think I posted several things to this effect on the original issue, but it was a big conversion either way. I may have understood it at one point but cannot recall :(

Issue summary:View changes

Removed issue retagged for D7 instead of D8 #939392: Localized date formats are initialized too late

Title:[META] Clean up, add consistency, fix dependencies for Localized Date Formats[META] Date format localisation is a huge mess, conflicts, does not work
Priority:Normal» Major
Issue tags:+sprint

Retitling so the problem is more evident, also raising to major.

Title:[META] Date format localisation is a huge mess, conflicts, does not work[META] Date format localisation is a huge mess, conflicts, does not work, regressed
Issue tags:+regression

Also a regression.

Issue summary:View changes

Updated issue summary.

Issue tags:+language-config

Issue summary:View changes

added task to do a full feature comparison to identify regressions

Issue summary:View changes

Added subtask

Closing that as duplicated, added #2059835: Implement translation interface for date formats as part of locale UI to the summary instead.

I opened #2098089: Date formats cannot be translated (the core UIs are useless) to cover this with schema. IMHO there is a very quick way in config_translation to solve it, and that would be the first step.

Issue summary:View changes

Removing duplicated

Issue tags:-sprint

Several other subissues are on sprint.

Issue summary:View changes

Added #2100351