NavigatorObserver: fix race condition on invoking TripSession#updateLegIndex for voice instructions (#6689)

Author: RingerJK

CHANGELOG.md

@@ -5,7 +5,8 @@ Mapbox welcomes participation and contributions from everyone.
 ## Unreleased
 #### Features
 #### Bug fixes and improvements
-- Fixed `BannerInstructions` issue where the banner instruction might have been removed from `RouteProgress` at some point around a edge's leg. [#6684](https://github.com/mapbox/mapbox-navigation-android/pull/6684)
+- Fixed an issue where `RouteProgress#BannerInstructions` could've become `null` when `MapboxNavigation#updateLegIndex` was called. [#6684](https://github.com/mapbox/mapbox-navigation-android/pull/6684)
+- Fixed an issue where `RouteProgress#VoiceInstructions` could've become `null` when `MapboxNavigation#updateLegIndex` was called. [#6689](https://github.com/mapbox/mapbox-navigation-android/pull/6689)
 
 ## Mapbox Navigation SDK 2.10.0-beta.2 - 01 December, 2022
 ### Changelog

libnavigation-core/src/main/java/com/mapbox/navigation/core/trip/session/MapboxTripSession.kt

@@ -179,7 +179,10 @@ internal class MapboxTripSession(
             this@MapboxTripSession.primaryRoute = newPrimaryRoute
             roadObjects = newPrimaryRoute?.upcomingRoadObjects ?: emptyList()
             isOffRoute = false
-            invalidateLatestInstructions(bannerInstructionEvent.latestInstructionWrapper)
+            invalidateLatestInstructions(
+                bannerInstructionEvent.latestInstructionWrapper,
+                lastVoiceInstruction
+            )
             routeProgress = null
         }.mapValue {
             it.alternatives
@@ -204,7 +207,9 @@ internal class MapboxTripSession(
     private val fallbackVersionsObservers = CopyOnWriteArraySet<FallbackVersionsObserver>()
 
     private val bannerInstructionEvent = BannerInstructionEvent()
-    private var lastVoiceInstruction: VoiceInstructions? = null
+
+    @VisibleForTesting
+    internal var lastVoiceInstruction: VoiceInstructions? = null
 
     private var state: TripSessionState = TripSessionState.STOPPED
         set(value) {
@@ -590,9 +595,10 @@ internal class MapboxTripSession(
         updateLegIndexJob = mainJobController.scope.launch {
             try {
                 val latestInstructionWrapper = bannerInstructionEvent.latestInstructionWrapper
+                val lastVoiceInstruction = lastVoiceInstruction
                 legIndexUpdated = navigator.updateLegIndex(legIndex)
                 if (legIndexUpdated) {
-                    invalidateLatestInstructions(latestInstructionWrapper)
+                    invalidateLatestInstructions(latestInstructionWrapper, lastVoiceInstruction)
                 }
             } finally {
                 callback.onLegIndexUpdatedCallback(legIndexUpdated)
@@ -701,14 +707,18 @@ internal class MapboxTripSession(
     }
 
     /**
-     * Invalidate latest banner instruction. To get the latest banner instruction wrapper call
-     * [BannerInstructionEvent.latestInstructionWrapper]
+     * Invalidate latest banner and voice instruction. To get the latest banner instruction wrapper call
+     * [BannerInstructionEvent.latestInstructionWrapper], to get the latest voice instruction
+     * call [lastVoiceInstruction]
      */
     private fun invalidateLatestInstructions(
-        latestInstructionWrapper: BannerInstructionEvent.LatestInstructionWrapper?
+        latestInstructionWrapper: BannerInstructionEvent.LatestInstructionWrapper?,
+        voiceInstruction: VoiceInstructions?,
     ) {
         bannerInstructionEvent.invalidateLatestBannerInstructions(latestInstructionWrapper)
-        lastVoiceInstruction = null
+        if (lastVoiceInstruction == voiceInstruction) {
+            lastVoiceInstruction = null
+        }
     }
 
     private fun checkBannerInstructionEvent(

libnavigation-core/src/test/java/com/mapbox/navigation/core/trip/session/MapboxTripSessionTest.kt

@@ -1670,7 +1670,7 @@ class MapboxTripSessionTest {
         latest banner instructions to remove legacy instructions only
      */
     @Test
-    fun `updateLegIndex latest banner instructions pre-save to later clen up them`() =
+    fun `updateLegIndex latest banner and voice instructions pre-save to later clean up them`() =
         coroutineRule.runBlockingTest {
             val idx = -1
             val mockLatestInstructionWrapper =
@@ -1681,15 +1681,19 @@ class MapboxTripSessionTest {
             coEvery { navigator.updateLegIndex(idx) } coAnswers {
                 true
             }
+            val mockVoiceInstruction = mockk<VoiceInstructions>()
 
+            tripSession.lastVoiceInstruction = mockVoiceInstruction
             tripSession.updateLegIndex(idx, mockk(relaxUnitFun = true))
 
             coVerifyOrder {
                 bannerInstructionEvent.latestInstructionWrapper
                 navigator.updateLegIndex(idx)
                 bannerInstructionEvent
                     .invalidateLatestBannerInstructions(mockLatestInstructionWrapper)
+                tripSession.lastVoiceInstruction = null
             }
+            assertNull(tripSession.lastVoiceInstruction)
         }
 
     @After