From 04f1b67a05c832a9ae9d9d50914ef58b8d4240b9 Mon Sep 17 00:00:00 2001
From: Dmitry Batkovich <dmitry.batkovich@jetbrains.com>
Date: Fri, 5 May 2017 14:47:06 +0300
Subject: [PATCH] javac ast indices: fix possible deadlock

---
 .../compiler/backwardRefs/CompilerReferenceServiceImpl.java     | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/java/compiler/impl/src/com/intellij/compiler/backwardRefs/CompilerReferenceServiceImpl.java b/java/compiler/impl/src/com/intellij/compiler/backwardRefs/CompilerReferenceServiceImpl.java
index 9d9e8d5e5741..3ce2edfec32d 100644
--- a/java/compiler/impl/src/com/intellij/compiler/backwardRefs/CompilerReferenceServiceImpl.java
+++ b/java/compiler/impl/src/com/intellij/compiler/backwardRefs/CompilerReferenceServiceImpl.java
@@ -343,9 +343,9 @@ public class CompilerReferenceServiceImpl extends CompilerReferenceServiceEx imp
 
   @Override
   public int getInheritorCount(@NotNull LightRef.LightClassHierarchyElementDef baseClass) throws ReferenceIndexUnavailableException {
-    if (myReader == null) throw new ReferenceIndexUnavailableException();
     myReadDataLock.lock();
     try {
+      if (myReader == null) throw new ReferenceIndexUnavailableException();
       LightRef.NamedLightRef[] hierarchy = myReader.getHierarchy(baseClass, false, true, -1);
       return hierarchy == null ? -1 : hierarchy.length;
     } catch (Exception e) {