From 4c471669ee7397a5593b6afc5e714220ff7ddcfe Mon Sep 17 00:00:00 2001
From: Alexey Kudravtsev <cdr@intellij.com>
Date: Thu, 16 Feb 2017 10:28:14 +0300
Subject: [PATCH] concurrency bug: cached value can be set to null while the
 other thread has already computed it in the meantime. This leads to multiple
 unnecessary re-computations.

---
 .../src/com/intellij/util/CachedValuesManagerImpl.java   | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/platform/core-impl/src/com/intellij/util/CachedValuesManagerImpl.java b/platform/core-impl/src/com/intellij/util/CachedValuesManagerImpl.java
index c837e564841e..28c2a6cd69e7 100644
--- a/platform/core-impl/src/com/intellij/util/CachedValuesManagerImpl.java
+++ b/platform/core-impl/src/com/intellij/util/CachedValuesManagerImpl.java
@@ -59,9 +59,12 @@ public class CachedValuesManagerImpl extends CachedValuesManager {
     if (dataHolder instanceof UserDataHolderEx) {
       UserDataHolderEx dh = (UserDataHolderEx)dataHolder;
       value = dh.getUserData(key);
-      if (isOutdated(value)) {
-        value = null;
-        dh.putUserData(key, null);
+      while (isOutdated(value)) {
+        if (dh.replace(key, value, null)) {
+          value = null;
+          break;
+        }
+        value = dh.getUserData(key);
       }
       if (value == null) {
         value = createCachedValue(provider, trackValue);