Bug 1740067 is adding preferences to enable live language switching in Firefox.

As part of that work, we should check that the search service correctly loads the new configuration for the search engines and applies it appropriately.

I think we shouldn't need to do any extra work, the search service has code to handle it already.

However, we should do some verification work to ensure that is still working, and at a minimum update the comment in the code.

Could you give me an steps to reproduce to verify this?

Uncaught TypeError: can't access property "select", gEngineView.selection is null
    remove chrome://browser/content/preferences/search.js:466
    observe chrome://browser/content/preferences/search.js:359
    notifyAction resource://gre/modules/SearchUtils.jsm:223
    _reloadEngines resource://gre/modules/SearchService.jsm:899

I'm noticing this error, but I'm not familiar with this code particularly.

The error you reference is because we're trying to update the Search Shortcuts tree when it isn't displayed. I'll file a bug for fixing it - it shouldn't actually be breaking anything though.

Generally, this is looking fine to me, however I would like to get our search QA team onto this sometime before we resolve it.

Here's basic steps for things to test:

• Set prefs:
  • browser.search.region: CN (note this will probably only last 2 weeks before it gets reset to your current region)
  • intl.multilingual.downloadEnabled: true
  • intl.multilingual.enabled: true
  • intl.multilingual.liveReload: true
• Assuming an en-US nightly build, download and install the zh-CN, fr and ru langauge packs from here
• Restart FF.
• Go into preferences, and under Language, add the languages.
• Test live switching between the different languages, and check:
  • Search engines change to the expected ones for the region/locale
  • Default search engine changes appropriately for the region/locale
  • Engine updates applied to address bar correctly
  • Engine updates applied to the search pane of preferences correctly
  • Also do some checks with removing the application provided engines, and checking that they don't return when switching back and forth.
    • (The tick to hide the one-off button currently doesn't stay hidden for switching languages - bug 1689986)

I've done various testing on this, and QA has as well - the issues are tracked in bug 1758726.