From 188d739400e10fc8571bbf2ec86d5cd338b04a5d Mon Sep 17 00:00:00 2001
From: Volker Hilsheimer <volker.hilsheimer@qt.io>
Date: Wed, 21 Jul 2021 16:31:29 +0200
Subject: [PATCH] Sync default action when checking tool button
 programmatically

QAbstractButton::setChecked is not virtual, so QToolButton cannot
override to synchronize the default action's checked state. This resulted
in button and default action not being in sync when the checked state
of the button was changed programmatically, while changing the checked
state on the action kept the button in sync.

Connect to the button's own toggled signal instead to keep the state of
the default action in sync. Make it a unique connection to allow multiple
calls to setDefaultAction, which are used by QToolButton to keep the
button updated if properties of the default action change.

Add a test that confirms that button and action are synchronized both
ways, and that we only get single signal emissions when changing either
programmatically.

Fixes: QTBUG-95255
Pick-to: 6.2 6.1
Change-Id: I0e027faf1da763ef1878e46e85bfa70073c8bf82
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>
---
 src/widgets/widgets/qtoolbutton.cpp           |  6 ++
 .../widgets/qtoolbutton/tst_qtoolbutton.cpp   | 59 +++++++++++++++++++
 2 files changed, 65 insertions(+)

diff --git a/src/widgets/widgets/qtoolbutton.cpp b/src/widgets/widgets/qtoolbutton.cpp
index b9d31bd657d..ee58797d3c4 100644
--- a/src/widgets/widgets/qtoolbutton.cpp
+++ b/src/widgets/widgets/qtoolbutton.cpp
@@ -961,6 +961,12 @@ void QToolButton::setDefaultAction(QAction *action)
     }
 #endif
     setCheckable(action->isCheckable());
+    if (action->isCheckable()) {
+        connect(this, &QAbstractButton::toggled, this, [this](bool checked) {
+            if (defaultAction())
+                defaultAction()->setChecked(checked);
+        }, Qt::UniqueConnection);
+    }
     setChecked(action->isChecked());
     setEnabled(action->isEnabled());
     if (action->d_func()->fontSet)
diff --git a/tests/auto/widgets/widgets/qtoolbutton/tst_qtoolbutton.cpp b/tests/auto/widgets/widgets/qtoolbutton/tst_qtoolbutton.cpp
index d6142dfcdcb..12a9ec3de0c 100644
--- a/tests/auto/widgets/widgets/qtoolbutton/tst_qtoolbutton.cpp
+++ b/tests/auto/widgets/widgets/qtoolbutton/tst_qtoolbutton.cpp
@@ -56,6 +56,7 @@ private slots:
     void task176137_autoRepeatOfAction();
     void qtbug_26956_popupTimerDone();
     void qtbug_34759_sizeHintResetWhenSettingMenu();
+    void defaultActionSynced();
 
 protected slots:
     void sendMouseClick();
@@ -280,5 +281,63 @@ void tst_QToolButton::qtbug_34759_sizeHintResetWhenSettingMenu()
     QTRY_COMPARE(button1.sizeHint(), button2.sizeHint());
 }
 
+void tst_QToolButton::defaultActionSynced()
+{
+    QAction a;
+    a.setCheckable(true);
+
+    QToolButton tb;
+    tb.setDefaultAction(&a);
+    QVERIFY(tb.isCheckable());
+
+    QSignalSpy tbSpy(&tb, SIGNAL(toggled(bool)));
+    QSignalSpy aSpy(&a, SIGNAL(toggled(bool)));
+
+    int tbToggledCount = 0;
+    int aToggledCount = 0;
+
+    tb.setChecked(true);
+    QVERIFY(a.isChecked());
+    QCOMPARE(tbSpy.count(), ++tbToggledCount);
+    QCOMPARE(aSpy.count(), ++aToggledCount);
+    tb.setChecked(false);
+    QVERIFY(!a.isChecked());
+    QCOMPARE(tbSpy.count(), ++tbToggledCount);
+    QCOMPARE(aSpy.count(), ++aToggledCount);
+
+    a.setChecked(true);
+    QVERIFY(tb.isChecked());
+    QCOMPARE(tbSpy.count(), ++tbToggledCount);
+    QCOMPARE(aSpy.count(), ++aToggledCount);
+    a.setChecked(false);
+    QVERIFY(!tb.isChecked());
+    QCOMPARE(tbSpy.count(), ++tbToggledCount);
+    QCOMPARE(aSpy.count(), ++aToggledCount);
+
+    QAction b;
+    QSignalSpy bSpy(&b, SIGNAL(toggled(bool)));
+    int bToggledCount = 0;
+    tb.setDefaultAction(&b);
+    QVERIFY(!tb.isCheckable());
+    b.setCheckable(true);
+    QVERIFY(tb.isCheckable());
+
+    tb.setChecked(true);
+    QVERIFY(!a.isChecked());
+    QVERIFY(b.isChecked());
+
+    QCOMPARE(tbSpy.count(), ++tbToggledCount);
+    QCOMPARE(aSpy.count(), aToggledCount);
+    QCOMPARE(bSpy.count(), ++bToggledCount);
+
+    tb.click();
+    QVERIFY(!a.isChecked());
+    QVERIFY(!tb.isChecked());
+    QVERIFY(!b.isChecked());
+    QCOMPARE(tbSpy.count(), ++tbToggledCount);
+    QCOMPARE(aSpy.count(), aToggledCount);
+    QCOMPARE(bSpy.count(), ++bToggledCount);
+}
+
 QTEST_MAIN(tst_QToolButton)
 #include "tst_qtoolbutton.moc"