From 2fa02d1344238b1744ecde5bb364ebcf499aa858 Mon Sep 17 00:00:00 2001
From: Maxim Shafirov <max@jetbrains.com>
Date: Mon, 26 Oct 2009 15:59:33 +0300
Subject: [PATCH] Accessing PSI requires read action.

---
 .../codeInsight/completion/CompletionContributor.java  | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/platform/lang-api/src/com/intellij/codeInsight/completion/CompletionContributor.java b/platform/lang-api/src/com/intellij/codeInsight/completion/CompletionContributor.java
index 49b203ce2c2c..5a78fb069e72 100644
--- a/platform/lang-api/src/com/intellij/codeInsight/completion/CompletionContributor.java
+++ b/platform/lang-api/src/com/intellij/codeInsight/completion/CompletionContributor.java
@@ -19,8 +19,10 @@ import com.intellij.codeInsight.lookup.LookupElement;
 import com.intellij.codeInsight.lookup.LookupElementPresentation;
 import com.intellij.lang.Language;
 import com.intellij.openapi.actionSystem.ActionManager;
+import com.intellij.openapi.application.ApplicationManager;
 import com.intellij.openapi.editor.Editor;
 import com.intellij.openapi.keymap.KeymapUtil;
+import com.intellij.openapi.util.Computable;
 import com.intellij.openapi.util.KeyedExtensionCollector;
 import com.intellij.openapi.util.Pair;
 import com.intellij.patterns.ElementPattern;
@@ -213,8 +215,12 @@ public abstract class CompletionContributor extends AbstractCompletionContributo
     return KeymapUtil.getFirstKeyboardShortcutText(ActionManager.getInstance().getAction(actionId));
   }
 
-  public static List<CompletionContributor> forParameters(CompletionParameters parameters) {
-    return forLanguage(PsiUtilBase.getLanguageAtOffset(parameters.getPosition().getContainingFile(), parameters.getOffset()));
+  public static List<CompletionContributor> forParameters(final CompletionParameters parameters) {
+    return ApplicationManager.getApplication().runReadAction(new Computable<List<CompletionContributor>>() {
+      public List<CompletionContributor> compute() {
+        return forLanguage(PsiUtilBase.getLanguageAtOffset(parameters.getPosition().getContainingFile(), parameters.getOffset()));
+      }
+    });
   }
 
   public static List<CompletionContributor> forLanguage(Language language) {