vcs: work around 'coroutineToIndicator' cancellation

GitOrigin-RevId: 91a873513decc6fec836654310e3e3f3b6b44e7a

platform/vcs-impl/src/com/intellij/openapi/vcs/changes/ui/AsyncChangesTree.kt

@@ -124,7 +124,7 @@ abstract class AsyncChangesTree : ChangesTree {
 
   private fun start() {
     scope.launch {
-      _requests.collectLatest { request ->
+      _requests.asyncCollectLatest(scope) { request ->
         handleRequest(request)
       }
     }
@@ -287,3 +287,19 @@ abstract class TwoStepAsyncChangesTreeModel<T>(val scope: CoroutineScope) : Asyn
     return newJob.await()
   }
 }
+
+/**
+ * [coroutineToIndicator]-friendly [collectLatest] implementation. Otherwise, indicator will never be cancelled.
+ */
+private suspend fun <T> Flow<T>.asyncCollectLatest(scope: CoroutineScope, action: suspend (value: T) -> Unit) {
+  var lastJob: Job? = null
+  collect { request ->
+    lastJob?.let {
+      it.cancel()
+      it.join()
+    }
+    lastJob = scope.launch {
+      action(request)
+    }
+  }
+}