From 1e263274720ea7b73530bd9f249655f783b56efe Mon Sep 17 00:00:00 2001
From: Jarek Kobus <jaroslaw.kobus@qt.io>
Date: Mon, 10 May 2021 18:05:50 +0200
Subject: [PATCH] Synchronize all started threads in SemanticHighlighter d'tor

This fixes a possible crash on session switch or on shutdown.

Task-number: QTCREATORBUG-25708
Change-Id: I5dcc2420dca27b9856f47616c6f465ae8f059942
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>
---
 src/plugins/qmljseditor/qmljssemantichighlighter.cpp | 6 ++++--
 src/plugins/qmljseditor/qmljssemantichighlighter.h   | 2 ++
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/plugins/qmljseditor/qmljssemantichighlighter.cpp b/src/plugins/qmljseditor/qmljssemantichighlighter.cpp
index b7e98ad0b7c..8fac6e91ec9 100644
--- a/src/plugins/qmljseditor/qmljssemantichighlighter.cpp
+++ b/src/plugins/qmljseditor/qmljssemantichighlighter.cpp
@@ -560,8 +560,10 @@ void SemanticHighlighter::rerun(const QmlJSTools::SemanticInfo &semanticInfo)
     m_watcher.cancel();
 
     m_startRevision = m_document->document()->revision();
-    m_watcher.setFuture(Utils::runAsync(QThread::LowestPriority,
-                                        &SemanticHighlighter::run, this, semanticInfo));
+    auto future = Utils::runAsync(QThread::LowestPriority, &SemanticHighlighter::run,
+                                  this, semanticInfo);
+    m_watcher.setFuture(future);
+    m_futureSynchronizer.addFuture(future);
 }
 
 void SemanticHighlighter::cancel()
diff --git a/src/plugins/qmljseditor/qmljssemantichighlighter.h b/src/plugins/qmljseditor/qmljssemantichighlighter.h
index 77ea2a7c122..ffa45bbaace 100644
--- a/src/plugins/qmljseditor/qmljssemantichighlighter.h
+++ b/src/plugins/qmljseditor/qmljssemantichighlighter.h
@@ -27,6 +27,7 @@
 
 #include <qmljseditor/qmljseditor_global.h>
 #include <texteditor/semantichighlighter.h>
+#include <QFutureSynchronizer>
 #include <QFutureWatcher>
 #include <QTextLayout>
 #include <QVector>
@@ -89,6 +90,7 @@ private:
     QHash<int, QTextCharFormat> m_formats;
     QHash<int, QTextCharFormat> m_extraFormats;
     QVector<QTextLayout::FormatRange> m_diagnosticRanges;
+    QFutureSynchronizer<void> m_futureSynchronizer;
 };
 
 } // namespace QmlJSEditor