@jhsoby @Amire80 Could you chime in?

@jhsoby Ping? :)

Note that we already use sr-ec and sr-el for terms (see language stats). The problem here is not that the codes are missing, it's that adding those codes to your Babel box does not cause them to appear in the term box.

I notice that after adding sr-ec and sr-el to the Babel box, the Babel box shows sr-Cyrl and sr-Latn and puts the user into categories for sr-Cyrl and sr-Latn. I suspect what's happening is that the codes get turned into sr-cyrl and sr-latn at some point before being passed to the term box and, since we don't support sr-cyrl or sr-latn, the term box fails to find a matching language and can't display them.

The opposite happens when loading a page using ?uselang=, both ?uselang=sr-el and ?uselang=sr-latn display the sr-el terms in the first row.

Thanks for the investigation, @Nikki! Yeah, I was confused when I saw this task because they *should* be available already. So if you have any idea how to fix it @Lydia_Pintscher, a fix would be appreciated!

Task Inspection notes:

Install Babel and add sr-el.
What does UserPreferredContentLanguagesLookup getLanguages() return? Does it have sr-el?
If not, look at places that pass data into UserPreferredContentLanguagesLookup. Look at the filtering or getAllUserLanguages.
If yes, look at places that consume that response.

Check if the language appears with JS disabled (differences between the lists of languages in the ui and on the server).

Change 673532 had a related patch set uploaded (by Tonina Zhelyazkova; owner: Tonina Zhelyazkova):
[mediawiki/core@master] Add sr-latn to Names of languages

https://gerrit.wikimedia.org/r/673532

Some findings:

As @Nikki commented, Termbox receives the code sr-latn, but Wikibase does not recognize it as a content language, therefor it's not visible in the termbox.
Wikibase uses MediaWiki's LanguageNameUtils to get a list of content languages. And from what I can tell the utils read from Names.php which is a list of language codes and their names. That list currently does not contain sr-latn but rather sr-el (see https://github.com/wikimedia/mediawiki/blob/master/languages/data/Names.php#L422). There are some mapping mechanisms which turn sr-el into sr-latn but that is of no use to us since we send sr-latn to the language util.

The only fix I could find (see the above gerrit change) is to add sr-latn to this Names.php list. I'm not sure that's the right place to solve the problem so I'll wait for a review from some WMF language people.

In T262269#6928952, @Tonina_Zhelyazkova_WMDE wrote:

Some findings:

As @Nikki commented, Termbox receives the code sr-latn, but Wikibase does not recognize it as a content language, therefor it's not visible in the termbox.
Wikibase uses MediaWiki's LanguageNameUtils to get a list of content languages. And from what I can tell the utils read from Names.php which is a list of language codes and their names. That list currently does not contain sr-latn but rather sr-el (see https://github.com/wikimedia/mediawiki/blob/master/languages/data/Names.php#L422). There are some mapping mechanisms which turn sr-el into sr-latn but that is of no use to us since we send sr-latn to the language util.

The only fix I could find (see the above gerrit change) is to add sr-latn to this Names.php list. I'm not sure that's the right place to solve the problem so I'll wait for a review from some WMF language people.

That sounds like it will add sr-latn alongside sr-el, i.e. without migrating the sr-el data to sr-latn, without preventing people from using sr-el instead of sr-latn and without sr-el in a user's Babel box causing the sr-el data to be shown in the termbox. If so, the problem would still exist - we would still have/allow data stored using a language code which users can't add to the termbox.

Change 673532 abandoned by Tonina Zhelyazkova:

[mediawiki/core@master] Add sr-latn to Names of languages

Reason:

https://gerrit.wikimedia.org/r/673532