IJPL-149752 Scanning should increase mod count only when dumb indexing won't be scheduled

GitOrigin-RevId: 6db0454e2eb414923d2c081529cc7a9582286bbb

platform/lang-impl/src/com/intellij/util/indexing/PerProjectIndexingQueue.kt

@@ -152,18 +152,20 @@ class PerProjectIndexingQueue(private val project: Project) {
   @Volatile
   private var allowFlushing: Boolean = true
 
-  fun flushNow(reason: String) {
+  fun flushNow(reason: String): Boolean {
     if (!allowFlushing) {
       LOG.info("Flushing is not allowed at the moment")
-      return
+      return false
     }
     val snapshot = getAndResetQueuedFiles()
-    if (snapshot.size > 0) {
+    return if (snapshot.size > 0) {
       // note that DumbModeWhileScanningTrigger will not finish dumb mode until scanning is finished
       UnindexedFilesIndexer(project, snapshot, reason).queue(project)
+      true
     }
     else {
       LOG.info("Finished for " + project.name + ". No files to index with loading content.")
+      false
     }
   }
 

platform/lang-impl/src/com/intellij/util/indexing/UnindexedFilesScannerExecutorImpl.kt

@@ -109,7 +109,10 @@ class UnindexedFilesScannerExecutorImpl(private val project: Project, cs: Corout
                 } finally {
                   // Scanning may throw exception (or error).
                   // In this case, we should either clear or flush the indexing queue; otherwise, dumb mode will not end in the project.
-                  project.service<PerProjectIndexingQueue>().flushNow(task.task.indexingReason)
+                  val indexingScheduled = project.service<PerProjectIndexingQueue>().flushNow(task.task.indexingReason)
+                  if (!indexingScheduled) {
+                    modCount.incrementAndGet()
+                  }
                 }
               }
             }
@@ -139,7 +142,6 @@ class UnindexedFilesScannerExecutorImpl(private val project: Project, cs: Corout
           // We don't care about finishing scanning without a write action. This looks harmless at the moment
           isRunning.value = false
           startedOrStoppedEvent.getAndUpdate(Int::inc)
-          modCount.incrementAndGet()
         }
       }
     }