IDEA-150943 Strange code folding in a method with lambda

java/java-tests/testSrc/com/intellij/codeInsight/folding/JavaFoldingTest.groovy

@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2015 JetBrains s.r.o.
+ * Copyright 2000-2016 JetBrains s.r.o.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -24,6 +24,7 @@ import com.intellij.openapi.application.ex.PathManagerEx
 import com.intellij.openapi.command.WriteCommandAction
 import com.intellij.openapi.editor.FoldRegion
 import com.intellij.openapi.editor.ex.DocumentEx
+import com.intellij.openapi.editor.ex.EditorEx
 import com.intellij.openapi.editor.ex.FoldingModelEx
 import com.intellij.openapi.editor.impl.FoldingModelImpl
 import com.intellij.openapi.fileEditor.impl.text.TextEditorProvider
@@ -36,7 +37,6 @@ import com.intellij.psi.search.GlobalSearchScope
 import com.intellij.testFramework.EditorTestUtil
 import com.intellij.testFramework.LightProjectDescriptor
 import com.intellij.testFramework.fixtures.LightCodeInsightFixtureTestCase
-
 /**
  * @author Denis Zhdanov
  * @since 1/17/11 1:00 PM
@@ -1185,6 +1185,38 @@ class Foo {
     myFixture.doHighlighting()
     assertTopLevelFoldRegionsState "[FoldRegion +(57:144), placeholder='(Runnable) () → { ', FoldRegion +(165:189), placeholder=' }']"
   }
+  
+  public void "test folding update after external change"() {
+    configure """\
+class Foo {
+  void m1() {
+    System.out.println(1);
+    System.out.println(2);
+  }
+  
+  void m2() {
+    System.out.println(3);
+    System.out.println(4);
+  }
+}
+"""
+    myFixture.performEditorAction(IdeActions.ACTION_COLLAPSE_ALL_REGIONS)
+    assertTopLevelFoldRegionsState "[FoldRegion +(24:83), placeholder='{...}', FoldRegion +(99:158), placeholder='{...}']"
+    
+    def virtualFile = ((EditorEx)myFixture.getEditor()).virtualFile
+    myFixture.saveText(virtualFile, """\
+class Foo {
+  void m1() {
+    System.out.println(1);
+    System.out.println(4);
+  }
+}
+""")
+    virtualFile.refresh(false, false)
+    
+    myFixture.doHighlighting()
+    assertTopLevelFoldRegionsState "[FoldRegion +(24:83), placeholder='{...}']"
+  }
 
   private void assertTopLevelFoldRegionsState(String expectedState) {
     assertEquals(expectedState, myFixture.editor.foldingModel.toString())

platform/lang-impl/src/com/intellij/codeInsight/folding/impl/UpdateFoldRegionsOperation.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2015 JetBrains s.r.o.
+ * Copyright 2000-2016 JetBrains s.r.o.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -93,6 +93,8 @@ class UpdateFoldRegionsOperation implements Runnable {
     List<FoldRegion> newRegions = addNewRegions(info, foldingModel, elementsToFold, rangeToExpandStatusMap, shouldExpand, groupExpand);
 
     applyExpandStatus(newRegions, shouldExpand, groupExpand);
+    
+    foldingModel.clearExternalChangeFlag();
   }
 
   private static void applyExpandStatus(@NotNull List<FoldRegion> newRegions,
@@ -248,7 +250,10 @@ class UpdateFoldRegionsOperation implements Runnable {
   }
 
   private boolean regionCanBeRemovedWhenCollapsed(FoldRegion region) {
-    return Boolean.TRUE.equals(region.getUserData(CAN_BE_REMOVED_WHEN_COLLAPSED)) || !region.isValid() || isRegionInCaretLine(region);
+    return Boolean.TRUE.equals(region.getUserData(CAN_BE_REMOVED_WHEN_COLLAPSED)) || 
+           ((FoldingModelEx)myEditor.getFoldingModel()).documentHasBeenChangedExternally() || 
+           !region.isValid() || 
+           isRegionInCaretLine(region);
   }
 
   private boolean isRegionInCaretLine(FoldRegion region) {

platform/lang-impl/src/com/intellij/injected/editor/FoldingModelWindow.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2015 JetBrains s.r.o.
+ * Copyright 2000-2016 JetBrains s.r.o.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -200,6 +200,15 @@ class FoldingModelWindow implements FoldingModelEx{
     return result;
   }
 
+  @Override
+  public boolean documentHasBeenChangedExternally() {
+    return false;
+  }
+
+  @Override
+  public void clearExternalChangeFlag() {
+  }
+
   @Override
   public void clearFoldRegions() {
     myDelegate.clearFoldRegions();

platform/platform-impl/src/com/intellij/openapi/editor/ex/FoldingModelEx.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2015 JetBrains s.r.o.
+ * Copyright 2000-2016 JetBrains s.r.o.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -64,4 +64,8 @@ public interface FoldingModelEx extends FoldingModel {
   
   @NotNull
   List<FoldRegion> getGroupedRegions(FoldingGroup group);
+  
+  boolean documentHasBeenChangedExternally();
+  
+  void clearExternalChangeFlag();
 }

platform/platform-impl/src/com/intellij/openapi/editor/impl/FoldingModelImpl.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2015 JetBrains s.r.o.
+ * Copyright 2000-2016 JetBrains s.r.o.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -26,6 +26,7 @@ package com.intellij.openapi.editor.impl;
 
 import com.intellij.diagnostic.Dumpable;
 import com.intellij.openapi.Disposable;
+import com.intellij.openapi.application.ApplicationManager;
 import com.intellij.openapi.application.ex.ApplicationManagerEx;
 import com.intellij.openapi.diagnostic.Logger;
 import com.intellij.openapi.editor.*;
@@ -36,6 +37,7 @@ import com.intellij.openapi.editor.markup.TextAttributes;
 import com.intellij.openapi.util.Disposer;
 import com.intellij.openapi.util.Key;
 import com.intellij.openapi.util.ModificationTracker;
+import com.intellij.psi.ExternalChangeAction;
 import com.intellij.util.containers.ContainerUtil;
 import com.intellij.util.containers.MultiMap;
 import org.jetbrains.annotations.NotNull;
@@ -65,6 +67,7 @@ public class FoldingModelImpl implements FoldingModelEx, PrioritizedInternalDocu
   private int mySavedCaretShift;
   private final MultiMap<FoldingGroup, FoldRegion> myGroups = new MultiMap<FoldingGroup, FoldRegion>();
   private boolean myDocumentChangeProcessed = true;
+  private boolean myDocumentHasBeenChangedExternally;
   private final AtomicLong myExpansionCounter = new AtomicLong();
 
   public FoldingModelImpl(EditorImpl editor) {
@@ -532,6 +535,7 @@ public class FoldingModelImpl implements FoldingModelEx, PrioritizedInternalDocu
       if (!((DocumentEx)event.getDocument()).isInBulkUpdate()) {
         updateCachedOffsets();
       }
+      if (ApplicationManager.getApplication().hasWriteAction(ExternalChangeAction.class)) myDocumentHasBeenChangedExternally = true;
     }
     finally {
       myDocumentChangeProcessed = true;
@@ -593,4 +597,14 @@ public class FoldingModelImpl implements FoldingModelEx, PrioritizedInternalDocu
   public long getModificationCount() {
     return myExpansionCounter.get();
   }
+
+  @Override
+  public boolean documentHasBeenChangedExternally() {
+    return myDocumentHasBeenChangedExternally;
+  }
+
+  @Override
+  public void clearExternalChangeFlag() {
+    myDocumentHasBeenChangedExternally = false;
+  }
 }