fix: preserve pending description flush during in-flight save

app/src/main/java/space/hackenslacker/kanbn4droid/app/carddetail/CardDetailViewModel.kt

@@ -76,6 +76,7 @@ class CardDetailViewModel(
     private var lastAttemptedComment: String? = null
 
     private var inFlightDescriptionPayload: String? = null
+    private var pendingDescriptionPayload: String? = null
     private var descriptionDebounceJob: Job? = null
 
     fun load() {
@@ -367,16 +368,20 @@ class CardDetailViewModel(
         }
         val normalized = rawDescription
         if (!fromRetry && normalized == persistedDescription) {
-            _uiState.update { it.copy(isDescriptionDirty = false) }
+            _uiState.update { it.copy(isDescriptionDirty = it.description != persistedDescription) }
             return
         }
         if (!fromRetry && normalized == inFlightDescriptionPayload) {
             return
         }
         if (_uiState.value.isDescriptionSaving) {
+            if (normalized != inFlightDescriptionPayload) {
+                pendingDescriptionPayload = normalized
+            }
             return
         }
         lastAttemptedDescription = normalized
+        pendingDescriptionPayload = null
 
         viewModelScope.launch {
             inFlightDescriptionPayload = normalized
@@ -385,10 +390,10 @@ class CardDetailViewModel(
                 is CardDetailRepository.Result.Success -> {
                     persistedDescription = normalized
                     _uiState.update {
+                        val stillDirty = it.description != persistedDescription
                         it.copy(
-                            description = normalized,
                             isDescriptionSaving = false,
-                            isDescriptionDirty = false,
+                            isDescriptionDirty = stillDirty,
                             descriptionErrorMessage = null,
                         )
                     }
@@ -408,13 +413,18 @@ class CardDetailViewModel(
                     _uiState.update {
                         it.copy(
                             isDescriptionSaving = false,
-                            isDescriptionDirty = true,
+                            isDescriptionDirty = it.description != persistedDescription,
                             descriptionErrorMessage = result.message,
                         )
                     }
                 }
             }
             inFlightDescriptionPayload = null
+
+            val pending = pendingDescriptionPayload
+            if (!_uiState.value.isSessionExpired && pending != null && pending != persistedDescription) {
+                saveDescription(pending)
+            }
         }
     }
 

app/src/test/java/space/hackenslacker/kanbn4droid/app/carddetail/CardDetailViewModelTest.kt

@@ -181,6 +181,44 @@ class CardDetailViewModelTest {
         assertFalse(viewModel.uiState.value.isDescriptionDirty)
     }
 
+    @Test
+    fun onStopDuringInflightSave_preservesPendingLatest_andDirtyUntilLatestCompletes() = runTest {
+        val firstGate = CompletableDeferred<Unit>()
+        val secondGate = CompletableDeferred<Unit>()
+        val repository = FakeCardDetailDataSource(
+            loadCardResult = CardDetailRepository.Result.Success(sampleCardDetail()),
+            listActivitiesResult = CardDetailRepository.Result.Success(emptyList()),
+            updateDescriptionGates = ArrayDeque(listOf(firstGate, secondGate)),
+        )
+        val viewModel = loadedViewModel(this, repository)
+
+        viewModel.onDescriptionChanged("first")
+        advanceTimeBy(800)
+        runCurrent()
+        assertEquals(listOf("first"), repository.updateDescriptionPayloads)
+
+        viewModel.onDescriptionChanged("second")
+        viewModel.onStop()
+        runCurrent()
+        assertEquals(1, repository.updateDescriptionCalls)
+
+        firstGate.complete(Unit)
+        runCurrent()
+
+        assertEquals(listOf("first", "second"), repository.updateDescriptionPayloads)
+        assertTrue(viewModel.uiState.value.isDescriptionDirty)
+        assertTrue(viewModel.uiState.value.isDescriptionSaving)
+        assertEquals("second", viewModel.uiState.value.description)
+
+        secondGate.complete(Unit)
+        advanceUntilIdle()
+
+        assertEquals(listOf("first", "second"), repository.updateDescriptionPayloads)
+        assertFalse(viewModel.uiState.value.isDescriptionDirty)
+        assertFalse(viewModel.uiState.value.isDescriptionSaving)
+        assertEquals("second", viewModel.uiState.value.description)
+    }
+
     @Test
     fun addComment_success_closesDialog_showsSnackbar_refreshesActivities() = runTest {
         val repository = FakeCardDetailDataSource(
@@ -328,6 +366,7 @@ class CardDetailViewModelTest {
         var updateDueDateResult: CardDetailRepository.Result<Unit> = CardDetailRepository.Result.Success(Unit),
         var addCommentResult: CardDetailRepository.Result<Unit> = CardDetailRepository.Result.Success(Unit),
         var updateDescriptionGate: CompletableDeferred<Unit>? = null,
+        var updateDescriptionGates: ArrayDeque<CompletableDeferred<Unit>> = ArrayDeque(),
     ) : CardDetailDataSource {
         var loadCalls: Int = 0
         var updateTitleCalls: Int = 0
@@ -355,6 +394,9 @@ class CardDetailViewModelTest {
         override suspend fun updateDescription(cardId: String, description: String): CardDetailRepository.Result<Unit> {
             updateDescriptionCalls += 1
             updateDescriptionPayloads += description
+            if (updateDescriptionGates.isNotEmpty()) {
+                updateDescriptionGates.removeFirst().await()
+            }
             updateDescriptionGate?.await()
             return updateDescriptionResult
         }