IDEA-177899 Exception thrown when removing valid FoldRegion

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

@@ -315,10 +315,8 @@ public class FoldingModelImpl implements FoldingModelEx, PrioritizedInternalDocu
     }
     FoldRegion[] regions = getAllFoldRegions();
     for (FoldRegion region : regions) {
-      if (!region.isExpanded()) {
-        notifyListenersOnFoldRegionStateChange(region);
-        myFoldRegionsProcessed = true;
-      }
+      if (!region.isExpanded()) notifyListenersOnFoldRegionStateChange(region);
+      region.dispose();
     }
     doClearFoldRegions();
   }

platform/platform-tests/testSrc/com/intellij/openapi/editor/impl/EditorStressTest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2016 JetBrains s.r.o.
+ * Copyright 2000-2017 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.
@@ -22,6 +22,7 @@ import com.intellij.openapi.editor.FoldingModel;
 import com.intellij.openapi.editor.Inlay;
 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.util.Disposer;
 
 import javax.swing.*;
@@ -45,6 +46,7 @@ public class EditorStressTest extends AbstractEditorTest {
                                                                          new RemoveFoldRegion(),
                                                                          new CollapseFoldRegion(),
                                                                          new ExpandFoldRegion(),
+                                                                         new ClearFoldRegions(),
                                                                          new ChangeBulkModeState(),
                                                                          new ChangeEditorVisibility(),
                                                                          new AddInlay(),
@@ -197,6 +199,16 @@ public class EditorStressTest extends AbstractEditorTest {
     }
   }
   
+  private static class ClearFoldRegions implements Action {
+    @Override
+    public void perform(final EditorEx editor, Random random) {
+      DocumentEx document = editor.getDocument();
+      if (document.isInBulkUpdate()) return;
+      FoldingModelEx foldingModel = editor.getFoldingModel();
+      foldingModel.runBatchFoldingOperation(() -> foldingModel.clearFoldRegions());
+    }
+  }
+  
   private static class ChangeBulkModeState implements Action {
     @Override
     public void perform(EditorEx editor, Random random) {

platform/platform-tests/testSrc/com/intellij/openapi/editor/impl/FoldingTest.java

@@ -357,4 +357,10 @@ public class FoldingTest extends AbstractEditorTest {
     WriteCommandAction.runWriteCommandAction(ourProject, () -> myEditor.getDocument().deleteString(15, 20));
     Assert.assertArrayEquals(new FoldRegion[]{inner}, myModel.fetchTopLevel());
   }
+  
+  public void testClearingInvalidatesFoldRegions() {
+    FoldRegion region = addCollapsedFoldRegion(5, 10, "...");
+    myModel.runBatchFoldingOperation(() -> myModel.clearFoldRegions());
+    assertFalse(region.isValid());
+  }
 }