fix(media-check): show errors instead of crashing

[criticalAY]

Note

Assisted-by: Opus 5.5 (Analysis of root cause)

Purpose / Description

Opening Check Media crashes the app if the backend throws. On GrapheneOS with Storage Scopes, listing an empty folder (usually media.trash) fails with Operation not permitted (os error 1), so every check crashes.

All five MediaCheckViewModel ops were a bare viewModelScope.launch, so a failure went straight to the uncaught exception handler. The fragment's launchCatchingTask { op().join() } couldn't catch it, because join() returns normally when the job fails. The check on open wasn't wrapped at all. This has been broken since 2.21alpha14.

Fixes

• Fixes [checkMedia] BackendIoException: Operation not permitted (os error 1) #22075

Approach

The ViewModel ran its operations with viewModelScope.launch, so a failure went straight to the uncaught exception handler. Wrapping them in launchCatchingTask did not help: join() returns normally when the job fails, and the check on open was not wrapped at all.

So the operations now return a Deferred which the fragment awaits, so failures reach launchCatchingTask and show the usual error dialog. sThe result dialogs are no longer shown after a failure.

How Has This Been Tested?

• New MediaCheckFragmentTest

Learning (optional, can help others)

NA

Checklist

Please, go through these checks before submitting the PR.

• You have a descriptive commit message with a short title (first line, max 50 chars).
• You have commented your code, particularly in hard-to-understand areas
• You have performed a self-review of your own code
• UI changes: include screenshots of all affected screens (in particular showing any new or changed strings)
• UI Changes: You have tested your change using the Google Accessibility Scanner

[david-allison]

Sure! Can you add a TODO to move this error handling into the ViewModel?

Or if you have the capacity, do it here

[lukstbit]

LGTM!

[criticalAY]

Added a TODO for now

[david-allison]

e: file:///home/runner/work/Anki-Android/Anki-Android/AnkiDroid/src/test/java/com/ichi2/anki/mediacheck/MediaCheckFragmentTest.kt:72:36 Argument type mismatch: actual type is 'Int', but 'Boolean' was expected.
> Task :AnkiDroid:compilePlayDebugUnitTestKotlin FAILED
e: file:///home/runner/work/Anki-Android/Anki-Android/AnkiDroid/src/test/java/com/ichi2/anki/mediacheck/MediaCheckFragmentTest.kt:72:69 Argument already passed for this parameter.
e: file:///home/runner/work/Anki-Android/Anki-Android/AnkiDroid/src/test/java/com/ichi2/anki/mediacheck/MediaCheckFragmentTest.kt:72:69 No value passed for parameter 'button'.