From 492f13578e7d42c5f2fbb56f7a46b7fe1e6f2182 Mon Sep 17 00:00:00 2001
From: Jarek Kobus <jaroslaw.kobus@qt.io>
Date: Tue, 11 May 2021 09:26:15 +0200
Subject: [PATCH] Fix a possible crash in FindReferences on shutdown

Cancel and wait for all threads started by FindReferences
in its destructor.

Task-number: QTCREATORBUG-25711
Change-Id: I83c3ea832a173a7fff5c52e0c0136dfff2234afe
Reviewed-by: Eike Ziller <eike.ziller@qt.io>
---
 src/plugins/qmljseditor/qmljsfindreferences.cpp | 3 +++
 src/plugins/qmljseditor/qmljsfindreferences.h   | 3 +++
 2 files changed, 6 insertions(+)

diff --git a/src/plugins/qmljseditor/qmljsfindreferences.cpp b/src/plugins/qmljseditor/qmljsfindreferences.cpp
index a251e823062..06afc62d8a5 100644
--- a/src/plugins/qmljseditor/qmljsfindreferences.cpp
+++ b/src/plugins/qmljseditor/qmljsfindreferences.cpp
@@ -815,6 +815,7 @@ FindReferences::FindReferences(QObject *parent)
     m_watcher.setPendingResultsLimit(1);
     connect(&m_watcher, &QFutureWatcherBase::resultsReadyAt, this, &FindReferences::displayResults);
     connect(&m_watcher, &QFutureWatcherBase::finished, this, &FindReferences::searchFinished);
+    m_synchronizer.setCancelOnWait(true);
 }
 
 FindReferences::~FindReferences() = default;
@@ -922,6 +923,7 @@ void FindReferences::findUsages(const QString &fileName, quint32 offset)
     QFuture<Usage> result = Utils::runAsync(&find_helper, ModelManagerInterface::workingCopy(),
                                             modelManager->snapshot(), fileName, offset, QString());
     m_watcher.setFuture(result);
+    m_synchronizer.addFuture(result);
 }
 
 void FindReferences::renameUsages(const QString &fileName, quint32 offset,
@@ -937,6 +939,7 @@ void FindReferences::renameUsages(const QString &fileName, quint32 offset,
     QFuture<Usage> result = Utils::runAsync(&find_helper, ModelManagerInterface::workingCopy(),
                                             modelManager->snapshot(), fileName, offset, newName);
     m_watcher.setFuture(result);
+    m_synchronizer.addFuture(result);
 }
 
 QList<FindReferences::Usage> FindReferences::findUsageOfType(const QString &fileName, const QString &typeName)
diff --git a/src/plugins/qmljseditor/qmljsfindreferences.h b/src/plugins/qmljseditor/qmljsfindreferences.h
index ebfdad5a233..30c120503df 100644
--- a/src/plugins/qmljseditor/qmljsfindreferences.h
+++ b/src/plugins/qmljseditor/qmljsfindreferences.h
@@ -27,6 +27,8 @@
 
 #include "qmljseditor_global.h"
 
+#include <utils/futuresynchronizer.h>
+
 #include <QObject>
 #include <QFutureWatcher>
 #include <QPointer>
@@ -81,6 +83,7 @@ private:
 
     QPointer<Core::SearchResult> m_currentSearch;
     QFutureWatcher<Usage> m_watcher;
+    Utils::FutureSynchronizer m_synchronizer;
 };
 
 } // namespace QmlJSEditor