From 4257264826a95a03a7848dd2afafef6bf0961d98 Mon Sep 17 00:00:00 2001
From: peter <peter@jetbrains.com>
Date: Fri, 2 Dec 2016 15:10:08 +0100
Subject: [PATCH] remember background vfs refresh start trace in tests

to diagnose flaky "PSI/document/model changes are not allowed during highlighting"
---
 .../daemon/impl/FileStatusMap.java            |  4 +++-
 .../vfs/newvfs/RefreshSessionImpl.java        | 19 ++++++++++++++-----
 2 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/platform/analysis-impl/src/com/intellij/codeInsight/daemon/impl/FileStatusMap.java b/platform/analysis-impl/src/com/intellij/codeInsight/daemon/impl/FileStatusMap.java
index bca837742ed3..1b20d204087f 100644
--- a/platform/analysis-impl/src/com/intellij/codeInsight/daemon/impl/FileStatusMap.java
+++ b/platform/analysis-impl/src/com/intellij/codeInsight/daemon/impl/FileStatusMap.java
@@ -46,6 +46,8 @@ import java.util.concurrent.ConcurrentMap;
 
 public class FileStatusMap implements Disposable {
   private static final Logger LOG = Logger.getInstance("#com.intellij.codeInsight.daemon.impl.FileStatusMap");
+  public static final String CHANGES_NOT_ALLOWED_DURING_HIGHLIGHTING =
+    "PSI/document/model changes are not allowed during highlighting";
   private final Project myProject;
   private final Map<Document,FileStatus> myDocumentToStatusMap = new WeakHashMap<>(); // all dirty if absent
   private volatile boolean myAllowDirt = true;
@@ -170,7 +172,7 @@ public class FileStatusMap implements Disposable {
 
   private void assertAllowModifications() {
     try {
-      assert myAllowDirt : "PSI/document/model changes are not allowed during highlighting";
+      assert myAllowDirt : CHANGES_NOT_ALLOWED_DURING_HIGHLIGHTING;
     }
     finally {
       myAllowDirt = true; //give next test a chance
diff --git a/platform/platform-impl/src/com/intellij/openapi/vfs/newvfs/RefreshSessionImpl.java b/platform/platform-impl/src/com/intellij/openapi/vfs/newvfs/RefreshSessionImpl.java
index 285b077b4ed5..73f55d98c98c 100644
--- a/platform/platform-impl/src/com/intellij/openapi/vfs/newvfs/RefreshSessionImpl.java
+++ b/platform/platform-impl/src/com/intellij/openapi/vfs/newvfs/RefreshSessionImpl.java
@@ -15,6 +15,7 @@
  */
 package com.intellij.openapi.vfs.newvfs;
 
+import com.intellij.codeInsight.daemon.impl.FileStatusMap;
 import com.intellij.openapi.application.*;
 import com.intellij.openapi.diagnostic.Logger;
 import com.intellij.openapi.project.DumbServiceImpl;
@@ -63,13 +64,15 @@ public class RefreshSessionImpl extends RefreshSession {
     myModalityState = modalityState;
     myTransaction = ((TransactionGuardImpl)TransactionGuard.getInstance()).getModalityTransaction(modalityState);
     LOG.assertTrue(modalityState == ModalityState.NON_MODAL || modalityState != ModalityState.any(), "Refresh session should have a specific modality");
+    myStartTrace = rememberStartTrace();
+  }
 
-    if (modalityState == ModalityState.NON_MODAL) {
-      myStartTrace = null;
-    }
-    else {
-      myStartTrace = new Throwable(); // please report exceptions here to peter
+  private Throwable rememberStartTrace() {
+    if (ApplicationManager.getApplication().isUnitTestMode() &&
+        (myIsAsync || !ApplicationManager.getApplication().isDispatchThread())) {
+      return new Throwable();
     }
+    return myModalityState == ModalityState.NON_MODAL ? null : new Throwable();
   }
 
   public RefreshSessionImpl(@NotNull List<VFileEvent> events) {
@@ -194,6 +197,12 @@ public class RefreshSessionImpl extends RefreshSession {
         scan();
       }
     }
+    catch (AssertionError e) {
+      if (FileStatusMap.CHANGES_NOT_ALLOWED_DURING_HIGHLIGHTING.equals(e.getMessage())) {
+        throw new AssertionError("VFS changes are not allowed during highlighting", myStartTrace);
+      }
+      throw e;
+    }
     finally {
       try {
         manager.fireAfterRefreshFinish(myIsAsync);