201: proper implementation for AsyncFileChangeListenerHelper.kt

updateFile is called before changes in vfs, so the timestamp is old there.
The proper implementation is to collect changed files in list and get timestamp in apply.

idea/idea-gradle/src/org/jetbrains/kotlin/idea/scripting/gradle/AsyncFileChangeListenerHelper.kt.201

@@ -6,6 +6,7 @@
 package org.jetbrains.kotlin.idea.scripting.gradle
 
 import com.intellij.openapi.externalSystem.autoimport.AsyncFileChangeListenerBase
+import com.intellij.openapi.vfs.LocalFileSystem
 import com.intellij.openapi.vfs.VirtualFile
 import com.intellij.openapi.vfs.VirtualFileManager
 import com.intellij.openapi.vfs.newvfs.events.VFileEvent
@@ -17,18 +18,27 @@ fun addVfsListener(
 ) {
     VirtualFileManager.getInstance().addAsyncFileListener(
         object : AsyncFileChangeListenerBase() {
+            val changedFiles = mutableListOf<String>()
+
+            override fun init() {
+                changedFiles.clear()
+            }
+
             override fun isRelevant(path: String): Boolean {
                 return buildRootsManager.maybeAffectedGradleProjectFile(path)
             }
 
             override fun updateFile(file: VirtualFile, event: VFileEvent) {
-                watcher.fileChanged(event.path, file.timeStamp)
+                changedFiles.add(event.path)
             }
 
-            // do nothing
-            override fun apply() {}
-            override fun init() {}
-
+            override fun apply() {
+                changedFiles.forEach {
+                    LocalFileSystem.getInstance().findFileByPath(it)?.let { f ->
+                        watcher.fileChanged(f.path, f.timeStamp)
+                    }
+                }
+            }
         },
         watcher.project
     )