ChangeManager: handling multiple exceptions in `notifySubscribers`

[david-allison]

If an exception is thrown by ref.opExecuted, other subscribers are not notified of a change

Anki-Android/AnkiDroid/src/main/java/com/ichi2/anki/observability/ChangeManager.kt

Lines 73 to 86 in 34878f0

	for (subscriber in subscribers) {
	val ref =
	try {
	subscriber.get()
	} catch (e: Exception) {
	CrashReportService.sendExceptionReport(e, "notifySubscribers", "16217: invalid subscriber")
	null
	}
	if (ref == null) {
	expired.add(subscriber)
	} else {
	ref.opExecuted(changes, handler)
	}
	}

What to do is open for discussion

This should likely be updated to:

• notify all subscribers
• Potentially throw an aggregate/composite exception
  • Should the caller of notifySubscribers care, or be fully decoupled from the subscribers

Related:

• [BUG] CongratsPage: onExecuted fails if not run on Main thread #19492

[xenonnn4w]

My plan: wrapping ref.opExecuted(changes, handler) in a try-catch, similar to how we handle subscriber.get() at line 75-80. This ensures all subscribers get notified even if one fails, and we still get crash reports via ACRA.
The caller shouldnt need to handle individual subscriber failures, it's more in line with the observer pattern to keep them decoupled.