Uninstalling language pack for current display language does not update display language setting

[Colengms]

This is similar to #79741 , but this is not a feature request. It's a bug. The language used in the UI becomes an inconsistent mix of 2 languages, and the current language setting remains set to something no longer valid and no longer available to the user.

Steps to repro:

1. Install a language pack.
2. Use 'Configure Display Language' command to set current display language to that language
3. Restart VS Code, as prompted
4. Uninstall the language pack
5. Restart VS Code

Seeing: VS Code has mostly fallen back to the default language, however there are still various strings in the other language. Extensions that use vscode-nls still display strings in the other language. (For example, all strings coming from the C/C++ Extension such as IntelliSense, are in the removed language. This appears to be true for some built-in VS Code extensions as well.).

Expected: When uninstalling the language pack for the currently selected display language, the setting should be reverted to the default language. Extensions that use vscode-nls should not still display the removed language. Note that the available languages in Configure Display Language only include languages there are language packs for, so it doesn't make sense for the current language setting to remain something not on that list.

Version: 1.39.2 (user setup)
Commit: 6ab5985
Date: 2019-10-15T15:35:18.241Z
Electron: 4.2.10
Chrome: 69.0.3497.128
Node.js: 10.11.0
V8: 6.9.427.31-electron.0
OS: Windows_NT x64 10.0.18362

[dbaeumer]

The problem here is that the setting still points to the removed language and that for example C++ ships with its own language bundle, hence that still wins.

@sandy081 is there an event that I can listen to when an extension is uninstalled. Then I could reset the setting.

[sandy081]

@dbaeumer What setting is this and how this is set? Where does this setting exists?

[dbaeumer]

It is not a setting. It is in its own file locale.json stored at the user data level (side by side to the settings.josn file).

[sandy081]

@dbaeumer This can be done here - https://github.com/microsoft/vscode/blob/master/src/vs/workbench/contrib/localizations/browser/localizations.contribution.ts#L48

I have code to check when a lang pack is installed, we can add here to check if a lang pack extension is uninstalled and it is currently active. Let me know if you want to handle this or I can do it.

[dbaeumer]

@sandy081 feel free to do the change. Is appreciated!

[sandy081]

@dbaeumer just to be sure, extensions are directly reading this file? If so why are not getting locale id from us?

[dbaeumer]

No, extension never read that file. They get the language id from us. It is more around removing a language id from the file if the LP gets uninstalled.