Unguarded navigation calls crash app with IllegalArgumentException

[sande11]

Summary

Two fatal crashes were reported in Crashlytics where Jetpack Navigation throws IllegalArgumentException because a navigation action is called from the wrong current destination. Both crashes occur on the same device session date (Apr 9 2026) and share the same root cause.

Crashes

Issue 522fe5fc — SubChapterFragment → BodyFragment

IllegalArgumentException: Navigation action/destination
action_subChapterFragment_to_bodyFragment cannot be found
from the current destination bodyFragment
at SubChapterFragment.onViewCreated$lambda$2(SubChapterFragment.kt:77)
Issue 5bd6be20 — MainFragment → SavedFragment

IllegalArgumentException: Navigation action/destination
action_mainFragment_to_savedFragment cannot be found
from the current destination chapterFragment
at MainFragment.onViewCreated$lambda$0(MainFragment.kt:237)

Root cause

Both crashes are triggered by a stale onKeyUp event (hardware key / D-pad) firing after a touch event has already completed the navigation. By the time the key-up fires, the current destination has changed and the action no longer exists from it.

Neither call site guards against this:

// SubChapterFragment.kt:77 — no destination check
findNavController().navigate(subChapterFragmentDirections)

// MainFragment.kt:237 — no destination check
findNavController().navigate(this)

Fix
Wrap each navigate() call with a current destination check before navigating:

// SubChapterFragment.kt
if (findNavController().currentDestination?.id == R.id.subChapterFragment) {
    findNavController().navigate(subChapterFragmentDirections)
}

// MainFragment.kt
if (findNavController().currentDestination?.id == R.id.mainFragment) {
    findNavController().navigate(MainFragmentDirections.actionMainFragmentToSavedFragment())
}

Scope

• MainFragment.kt
• BodyFragment.kt
• SubChapterFragment.kt
• ChapterFragment.kt, ChartFragment.kt, SavedFragment.kt, GlobalSearchFragment.kt, SettingsFragment.kt,

All of these are vulnerable to the same crash. The fix should be applied consistently across all call sites.