From 472d02996944c4fc73b2c13cf0ef48a44f4b76d1 Mon Sep 17 00:00:00 2001
From: Dmitry Batrak <Dmitry.Batrak@jetbrains.com>
Date: Tue, 20 Mar 2018 16:21:02 +0300
Subject: [PATCH] prevent fold regions from 'disappearing' if no one references
 them

supposedly fixes EA-107809 - AIOOBE: TIntArrayList.insert
---
 .../openapi/editor/impl/FoldRegionImpl.java   |  8 +++++++-
 .../openapi/editor/impl/FoldingModelImpl.java | 20 ++++++++++++++++++-
 2 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/platform/platform-impl/src/com/intellij/openapi/editor/impl/FoldRegionImpl.java b/platform/platform-impl/src/com/intellij/openapi/editor/impl/FoldRegionImpl.java
index a997cb37d67d..b4a0e062763e 100644
--- a/platform/platform-impl/src/com/intellij/openapi/editor/impl/FoldRegionImpl.java
+++ b/platform/platform-impl/src/com/intellij/openapi/editor/impl/FoldRegionImpl.java
@@ -7,11 +7,12 @@ import com.intellij.openapi.editor.Editor;
 import com.intellij.openapi.editor.FoldRegion;
 import com.intellij.openapi.editor.FoldingGroup;
 import com.intellij.openapi.editor.event.DocumentEvent;
+import com.intellij.openapi.util.Getter;
 import com.intellij.util.DocumentUtil;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
-class FoldRegionImpl extends RangeMarkerImpl implements FoldRegion {
+class FoldRegionImpl extends RangeMarkerImpl implements FoldRegion, Getter<FoldRegionImpl> {
   private boolean myIsExpanded;
   private final EditorImpl myEditor;
   private final String myPlaceholderText;
@@ -65,6 +66,11 @@ class FoldRegionImpl extends RangeMarkerImpl implements FoldRegion {
     }
   }
 
+  @Override
+  public FoldRegionImpl get() {
+    return this;
+  }
+
   private static void doSetExpanded(boolean expanded, FoldingModelImpl foldingModel, FoldRegion region, boolean notify) {
     if (expanded) {
       foldingModel.expandFoldRegion(region, notify);
diff --git a/platform/platform-impl/src/com/intellij/openapi/editor/impl/FoldingModelImpl.java b/platform/platform-impl/src/com/intellij/openapi/editor/impl/FoldingModelImpl.java
index 7040c5b6cb9d..00a9317e3bc2 100644
--- a/platform/platform-impl/src/com/intellij/openapi/editor/impl/FoldingModelImpl.java
+++ b/platform/platform-impl/src/com/intellij/openapi/editor/impl/FoldingModelImpl.java
@@ -15,6 +15,7 @@ import com.intellij.openapi.editor.ex.FoldingModelEx;
 import com.intellij.openapi.editor.ex.PrioritizedInternalDocumentListener;
 import com.intellij.openapi.editor.markup.TextAttributes;
 import com.intellij.openapi.util.Disposer;
+import com.intellij.openapi.util.Getter;
 import com.intellij.openapi.util.Key;
 import com.intellij.openapi.util.ModificationTracker;
 import com.intellij.util.DocumentUtil;
@@ -59,7 +60,24 @@ public class FoldingModelImpl implements FoldingModelEx, PrioritizedInternalDocu
     myIsFoldingEnabled = true;
     myIsBatchFoldingProcessing = false;
     myDoNotCollapseCaret = false;
-    myRegionTree = new RangeMarkerTree<>(editor.getDocument());
+    myRegionTree = new RangeMarkerTree<FoldRegionImpl>(editor.getDocument()) {
+      @NotNull
+      @Override
+      protected RMNode<FoldRegionImpl> createNewNode(@NotNull FoldRegionImpl key,
+                                                     int start,
+                                                     int end,
+                                                     boolean greedyToLeft,
+                                                     boolean greedyToRight,
+                                                     boolean stickingToRight,
+                                                     int layer) {
+        return new RMNode<FoldRegionImpl>(this, key, start, end, greedyToLeft, greedyToRight, stickingToRight) {
+          @Override
+          protected Getter<FoldRegionImpl> createGetter(@NotNull FoldRegionImpl region) {
+            return region;
+          }
+        };
+      }
+    };
     myFoldTree = new FoldRegionsTree(myRegionTree) {
       @Override
       protected boolean isFoldingEnabled() {