From b86efb1ab9daa76965cda5bdebb225c9e3762e8e Mon Sep 17 00:00:00 2001
From: Edward Welbourne <edward.welbourne@theqtcompany.com>
Date: Thu, 24 Sep 2015 11:03:38 +0200
Subject: [PATCH] Initialize QFutureWatcherBasePrivate::finished and test
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It's accessed by QFutureWatcherBase::isFinished(), potentially before
anything has set it.  It gets to be initially true until setFuture()
has given it us unfinished future and set it false.

Add a regression test for matching state in future and watcher.

Task-number: QTBUG-12358
Change-Id: Iae7bdaa434ab80f518afe4d7d55df99c391991a4
Reviewed-by: Frederik Gladhorn <frederik.gladhorn@theqtcompany.com>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Jędrzej Nowacki <jedrzej.nowacki@theqtcompany.com>
---
 src/corelib/thread/qfuturewatcher.cpp               |  7 ++++---
 .../thread/qfuturewatcher/tst_qfuturewatcher.cpp    | 13 +++++++++++++
 2 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/src/corelib/thread/qfuturewatcher.cpp b/src/corelib/thread/qfuturewatcher.cpp
index 3056216f6e..3863a47673 100644
--- a/src/corelib/thread/qfuturewatcher.cpp
+++ b/src/corelib/thread/qfuturewatcher.cpp
@@ -248,7 +248,7 @@ bool QFutureWatcherBase::isStarted() const
 /*! \fn bool QFutureWatcher::isFinished() const
 
     Returns \c true if the asynchronous computation represented by the future()
-    has finished; otherwise returns \c false.
+    has finished, or if no future has been set; otherwise returns \c false.
 */
 bool QFutureWatcherBase::isFinished() const
 {
@@ -379,7 +379,8 @@ void QFutureWatcherBase::disconnectNotify(const QMetaMethod &signal)
 */
 QFutureWatcherBasePrivate::QFutureWatcherBasePrivate()
     : maximumPendingResultsReady(QThread::idealThreadCount() * 2),
-      resultAtConnected(0)
+      resultAtConnected(0),
+      finished(true) /* the initial m_future is a canceledResult(), with Finished set */
 { }
 
 /*!
@@ -400,7 +401,7 @@ void QFutureWatcherBase::disconnectOutputInterface(bool pendingAssignment)
         d->pendingResultsReady.store(0);
         qDeleteAll(d->pendingCallOutEvents);
         d->pendingCallOutEvents.clear();
-        d->finished = false;
+        d->finished = false; /* May soon be amended, during connectOutputInterface() */
     }
 
     futureInterface().d->disconnectOutputInterface(d_func());
diff --git a/tests/auto/corelib/thread/qfuturewatcher/tst_qfuturewatcher.cpp b/tests/auto/corelib/thread/qfuturewatcher/tst_qfuturewatcher.cpp
index 60a4d749c9..5ec32b1d02 100644
--- a/tests/auto/corelib/thread/qfuturewatcher/tst_qfuturewatcher.cpp
+++ b/tests/auto/corelib/thread/qfuturewatcher/tst_qfuturewatcher.cpp
@@ -68,6 +68,7 @@ private slots:
     void incrementalFilterResults();
     void qfutureSynchronizer();
     void warnRace();
+    void matchFlags();
 };
 
 void sleeper()
@@ -930,5 +931,17 @@ void tst_QFutureWatcher::warnRace()
     future.waitForFinished();
 }
 
+void tst_QFutureWatcher::matchFlags()
+{
+    /* Regression test: expect a default watcher to be in the same state as a
+     * default future. */
+    QFutureWatcher<int> watcher;
+    QFuture<int> future;
+    QCOMPARE(watcher.isStarted(), future.isStarted());
+    QCOMPARE(watcher.isCanceled(), future.isCanceled());
+    QCOMPARE(watcher.isFinished(), future.isFinished());
+}
+
+
 QTEST_MAIN(tst_QFutureWatcher)
 #include "tst_qfuturewatcher.moc"