Rejecting promise in `registerSave` callback should revert changes to options page

[tdulcet]

Rejecting the promise in a registerSave callback should automatically revert any changes to the option page.

This line assumes that the promises will always resolve:

AutomaticSettings/internal/LoadAndSave.js

Line 54 in c88ded6

const saveTriggerValue = await Trigger.runSaveTrigger(option, optionValue, event);

It produces an "uncaught exception" error if they do not, which leaves the options page in an invalid state:

This is particularity an issue when using the PermissionRequest library.

The solution is probably for the library to call preventDefault() whenever the promise is rejected.

[rugk]

Did not look into the code too deeply, but what you say makes sense. Feel free to create a pr.

Just note initially that was not intended to fail/it could never fail or was expected to.

AutomaticSettings/internal/Trigger.js

Line 57 in c88ded6

* @return {Promise|void} optionally, to use await

Also it should probably not revert all changes but only the single option it is called for. In general ootions saving should always work.
Or to make it explicit we could introduce a new symbol.
Though in case of an error, i agree, it kinda makes sense to revert the setting to the currently saved one. (Though such logic can always fail and make stuff complex with custom options triggers etc.)

[rugk]

Also do you have a specific use case for that or is it just an idea in general?

[tdulcet]

Also do you have a specific use case for that or is it just an idea in general?

With the PermissionRequest library, if the user denies the permission request, the promise is rejected, which produces this issue. For example, try enabling the Omnibox option in the Awesome Emoji Picker, but then deny the clipboard write permission. The Omnibox option appears to still be enabled, when it is actually disabled.

Anyway, my specific use case was allowing the user to confirm a potenchally dangerous option change with window.confirm(). See: rugk/unicodify#72