backwards-compatibility issue in LocaleSwitcher.vue

[EffakT]

Description of the bug

Looks like commit 56c8393 caused a backwards compatibility issue.
When changing the clientSettings.locale.value default from auto to undefined, this caused a bug where if you don't re-select the locale from the dropdown the audio/subtitle selectors don't work, therefore you are unable to play a video.

Error caused is invalid language tag: "auto" in new Intl.DisplayNames() calls, where the first parameter is "auto", instead of "undefined".

Adding a logic of toCode !== "auto" ? toCode : undefined to the utils/i18n.ts file would likely work as a fallback.

Seeing how this UI is still experimental, I understand if this bug is not resolved, as it only affects past releases updating to the latest.

Steps to reproduce

1. Update from an older version, prior to 56c8393
2. Set locale to "auto"
3. Update to a version newer than 56c8393
4. Attempt to load a video
5. See select boxes failing to load

Expected behavior

Update should be backwards compatible.
After updating, settings should have updated automatically, or had a fallback.

Logs

Screenshots

No response

Platform

macOS

Browser

Firefox

Jellyfin server version

N/A

Additional context

[ferferga]

Seeing how this UI is still experimental, I understand if this bug is not resolved, as it only affects past releases updating to the latest.

Yeah, was going to pretty much say this :). Hopefully at some point everybody gets the data updated (this only affects english users as well, since users with other locales would see their client in English, hence manually changing the option (and having the new correct schema already).

Once we reach the stable status, we should make data migration paths for any changes as you say.

I will leave this open for reference in case some cames across the same problem. Thank you very much for your report!