LocalizationService.GetLanguageByIsoCode my return language different to the one requested

[KevinJump]

Calling the LocalizationService GetLanguageByIsoCode may return a 'parent' language to the one requested if it can't find it.

e.g GetLanguageByIsoCode("en-US") will return the "en" language if the en-US language is missing.

this may or may not be a bug but the method should be at least annotated to tell you that you might not get what you asked for - maybe there should be a fallback option exposed?

ultimately it happens in the repo:

Umbraco-CMS/src/Umbraco.Core/Persistence/Repositories/Implement/LanguageRepository.cs

Line 240 in e5956e4

public int? GetIdByIsoCode(string isoCode, bool throwOnNotFound = true)

[kjac]

For reference: The reason for doing so is described in #4519

The new option to localize the backoffice using the language files (#5358) may also weigh in on any decision to undo #4519 😄

[ronaldbarendse]

Ouch, that's not a change you would add to a repository, especially without opt-in! 😮

And PR #4519 doesn't correctly get the parent culture for cultures that contain multiple dashes or just different names (e.g. zh-Hans-HK, which parents are zh-CHS > zh-Hans > zh).

[kjac]

I'll pick this one up 👍

[kjac]

OK so... we can't solve this with an opt-in/overload on the affected method(s) without causing a breaking change on ILanguageRepository.

Given how #5358 now allows us to localize the backoffice independently of the dictionary and the active languages, perhaps the best approach here is to simply revert #4519 and no longer (attempt to) support fallbacks to culture invariant translations in the dictionary? Unless there is some Cloud implication I am unaware of here - can you have user defined language overrides on Cloud?

[nul800sebastiaan]

Thanks @kjac - I know you slept on it and had some more clever ideas, look forward to seeing those!

[kjac]

@nul800sebastiaan you got it 😆 new PR in #6090 reverts the changes from #4519 and adds the same feature by other means.

[nul800sebastiaan]

Fixed in #6090

Cherry picked to 8.1.3 in 87845ee