optimization: do not rebuild RootIndex when roots-unrelated directories changed

java/java-tests/testSrc/com/intellij/java/openapi/roots/impl/DirectoryIndexTest.java

@@ -2,6 +2,7 @@
 package com.intellij.java.openapi.roots.impl;
 
 import com.intellij.openapi.application.ApplicationManager;
+import com.intellij.openapi.application.WriteAction;
 import com.intellij.openapi.command.WriteCommandAction;
 import com.intellij.openapi.fileTypes.FileTypeManager;
 import com.intellij.openapi.fileTypes.ex.FileTypeManagerEx;
@@ -988,4 +989,24 @@ public class DirectoryIndexTest extends DirectoryIndexTestCase {
       assertEquals("Invalid package name for dir " + dir + ": " + packageName, packageName, actualName);
     }
   }
+
+  public void testUnrelatedDirectoriesCreationMustNotLeadToDirectoryIndexRebuildToImproveCheckoutPerformance() {
+    VirtualFile root = ModuleRootManager.getInstance(myModule).getContentRoots()[0];
+    WriteAction.run(()->ModuleRootModificationUtil.updateModel(myModule, model -> {
+      ContentEntry rootEntry = model.getContentEntries()[0];
+      for (int i=0;i<10_000;i++) {
+        VirtualFile src = createChildDirectory(root, "extsrc" + i);
+        rootEntry.addSourceFolder(src, false);
+      }
+    }));
+
+    ProjectFileIndex fileIndex = ProjectFileIndex.getInstance(getProject());
+    PlatformTestUtil.startPerformanceTest("dir creation must not lead to dirindex rebuild", 30_000, ()->{
+      for (int i=0; i<5_000; i++) {
+        VirtualFile xxx = createChildDirectory(root, "xxx");
+        assertFalse(fileIndex.isInSource(xxx));
+        delete(xxx);
+      }
+    }).assertTiming();
+  }
 }

platform/core-impl/src/com/intellij/openapi/roots/impl/PackageDirectoryCache.java

@@ -52,6 +52,11 @@ public class PackageDirectoryCache {
     }
   }
 
+  void clear() {
+    myNonExistentPackages.clear();
+    myDirectoriesByPackageNameCache.clear();
+  }
+
   public void onLowMemory() {
     myNonExistentPackages.clear();
   }
@@ -86,7 +91,7 @@ public class PackageDirectoryCache {
       }
 
       for (VirtualFile file : myRootsByPackagePrefix.get(packageName)) {
-        if (file.isDirectory()) {
+        if (file.isDirectory() && file.isValid()) {
           result.add(file);
         }
       }

platform/lang-impl/src/com/intellij/openapi/roots/impl/DirectoryIndexImpl.java

@@ -6,6 +6,7 @@ import com.intellij.openapi.diagnostic.Logger;
 import com.intellij.openapi.fileTypes.FileTypeEvent;
 import com.intellij.openapi.fileTypes.FileTypeListener;
 import com.intellij.openapi.fileTypes.FileTypeManager;
+import com.intellij.openapi.fileTypes.FileTypeRegistry;
 import com.intellij.openapi.module.Module;
 import com.intellij.openapi.progress.ProgressManager;
 import com.intellij.openapi.project.Project;
@@ -17,9 +18,12 @@ import com.intellij.openapi.util.Disposer;
 import com.intellij.openapi.util.LowMemoryWatcher;
 import com.intellij.openapi.vfs.VirtualFile;
 import com.intellij.openapi.vfs.VirtualFileManager;
+import com.intellij.openapi.vfs.ex.temp.TempFileSystem;
 import com.intellij.openapi.vfs.newvfs.BulkFileListener;
 import com.intellij.openapi.vfs.newvfs.NewVirtualFile;
 import com.intellij.openapi.vfs.newvfs.events.VFileEvent;
+import com.intellij.openapi.vfs.newvfs.events.VFileMoveEvent;
+import com.intellij.openapi.vfs.newvfs.events.VFilePropertyChangeEvent;
 import com.intellij.util.Query;
 import com.intellij.util.messages.MessageBusConnection;
 import org.jetbrains.annotations.NotNull;
@@ -64,6 +68,11 @@ public class DirectoryIndexImpl extends DirectoryIndex {
     });
 
     myConnection.subscribe(ProjectTopics.PROJECT_ROOTS, new ModuleRootListener() {
+      @Override
+      public void beforeRootsChange(@NotNull ModuleRootEvent event) {
+        myRootIndex = null;
+      }
+
       @Override
       public void rootsChanged(@NotNull ModuleRootEvent event) {
         myRootIndex = null;
@@ -75,7 +84,15 @@ public class DirectoryIndexImpl extends DirectoryIndex {
       public void after(@NotNull List<? extends VFileEvent> events) {
         RootIndex rootIndex = myRootIndex;
         if (rootIndex != null && shouldResetOnEvents(events)) {
-          myRootIndex = null;
+          rootIndex.myPackageDirectoryCache.clear();
+          for (VFileEvent event : events) {
+            // TempFileSystem doesn't properly support virtual file pointers, so reset unconditionally
+            if (event.getFileSystem() instanceof TempFileSystem ||
+                isIgnoredFileCreated(event)) {
+              myRootIndex = null;
+              break;
+            }
+          }
         }
       }
     });
@@ -91,6 +108,12 @@ public class DirectoryIndexImpl extends DirectoryIndex {
     return false;
   }
 
+  private static boolean isIgnoredFileCreated(@NotNull VFileEvent event) {
+    return event instanceof VFileMoveEvent && FileTypeRegistry.getInstance().isFileIgnored(((VFileMoveEvent)event).getNewParent()) ||
+           event instanceof VFilePropertyChangeEvent &&
+           ((VFilePropertyChangeEvent)event).getPropertyName().equals(VirtualFile.PROP_NAME) &&
+           FileTypeRegistry.getInstance().isFileIgnored(((VFilePropertyChangeEvent)event).getFile());
+  }
 
   private void dispatchPendingEvents() {
     myConnection.deliverImmediately();

platform/projectModel-impl/src/com/intellij/openapi/roots/impl/RootIndex.java

@@ -49,7 +49,7 @@ public class RootIndex {
   private final Map<VirtualFile, DirectoryInfo> myRootInfos = ContainerUtil.newHashMap();
   private final ConcurrentBitSet myNonInterestingIds = new ConcurrentBitSet();
   @NotNull private final Project myProject;
-  private final PackageDirectoryCache myPackageDirectoryCache;
+  final PackageDirectoryCache myPackageDirectoryCache;
   private OrderEntryGraph myOrderEntryGraph;
 
   public RootIndex(@NotNull Project project) {