From 0b15a1dd5f557a4d70dd3f8b629d50023e21b7de Mon Sep 17 00:00:00 2001
From: "Denis.Zhdanov" <Denis.Zhdanov@jetbrains.com>
Date: Fri, 25 May 2012 11:05:59 +0400
Subject: [PATCH] IDEA-86084 Foldings drop after 'rename file'

---
 .../folding/impl/FoldingUpdate.java           | 25 ++++++++++++++++---
 1 file changed, 22 insertions(+), 3 deletions(-)

diff --git a/platform/lang-impl/src/com/intellij/codeInsight/folding/impl/FoldingUpdate.java b/platform/lang-impl/src/com/intellij/codeInsight/folding/impl/FoldingUpdate.java
index 32d11c7fa6ed..51cf80b83161 100644
--- a/platform/lang-impl/src/com/intellij/codeInsight/folding/impl/FoldingUpdate.java
+++ b/platform/lang-impl/src/com/intellij/codeInsight/folding/impl/FoldingUpdate.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2009 JetBrains s.r.o.
+ * Copyright 2000-2012 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.
@@ -32,6 +32,7 @@ import com.intellij.openapi.project.Project;
 import com.intellij.openapi.util.Key;
 import com.intellij.openapi.util.Pair;
 import com.intellij.openapi.util.TextRange;
+import com.intellij.openapi.vfs.VirtualFile;
 import com.intellij.psi.*;
 import com.intellij.psi.impl.source.tree.injected.InjectedLanguageUtil;
 import com.intellij.psi.util.CachedValueProvider;
@@ -49,6 +50,7 @@ public class FoldingUpdate {
   private static final Logger LOG = Logger.getInstance("#com.intellij.codeInsight.folding.impl.FoldingUpdate");
 
   private static final Key<ParameterizedCachedValue<Runnable, Pair<Boolean,Boolean>>> CODE_FOLDING_KEY = Key.create("code folding");
+  private static final Key<String> CODE_FOLDING_FILE_EXTENSION_KEY = Key.create("code folding file extension");
 
   private static final Comparator<PsiElement> COMPARE_BY_OFFSET = new Comparator<PsiElement>() {
     public int compare(PsiElement element, PsiElement element1) {
@@ -67,13 +69,30 @@ public class FoldingUpdate {
     final Project project = file.getProject();
     final Document document = editor.getDocument();
     LOG.assertTrue(!PsiDocumentManager.getInstance(project).isUncommited(document));
+    
+    String currentFileExtension = null;
+    final VirtualFile virtualFile = file.getVirtualFile();
+    if (virtualFile != null) {
+      currentFileExtension = virtualFile.getExtension();
+    }
 
     ParameterizedCachedValue<Runnable, Pair<Boolean,Boolean>> value = editor.getUserData(CODE_FOLDING_KEY);
+    if (value != null) {
+      // There was a problem that old fold regions have been cached on file extension change (e.g. *.java -> *.groovy).
+      // We want to drop them in such circumstances.
+      final String oldExtension = editor.getUserData(CODE_FOLDING_FILE_EXTENSION_KEY);
+      if (oldExtension == null ? currentFileExtension != null : !oldExtension.equals(currentFileExtension)) {
+        value = null;
+        editor.putUserData(CODE_FOLDING_KEY, null);
+      }
+    }
+    editor.putUserData(CODE_FOLDING_FILE_EXTENSION_KEY, currentFileExtension);
+    
     if (value != null && value.hasUpToDateValue() && !applyDefaultState) return null;
     if (quick) return getUpdateResult(file, document, quick, project, editor, applyDefaultState).getValue();
     
-    return CachedValuesManager.getManager(project).getParameterizedCachedValue(editor, CODE_FOLDING_KEY,
-                                                                               new ParameterizedCachedValueProvider<Runnable, Pair<Boolean,Boolean>>() {
+    return CachedValuesManager.getManager(project).getParameterizedCachedValue(
+      editor, CODE_FOLDING_KEY, new ParameterizedCachedValueProvider<Runnable, Pair<Boolean, Boolean>>() {
       public CachedValueProvider.Result<Runnable> compute(Pair<Boolean,Boolean> param) {
         Document document = editor.getDocument();
         PsiFile file = PsiDocumentManager.getInstance(project).getPsiFile(document);