QToolButton: properly reset the size hint when a menu is set on it

QToolButton::sizeHint() takes into account the presence of a menu.
However, setMenu() doesn't retrigger a size hint recalculation. Hence,
(un)setting a menu on an already sized tool button won't properly
reset the size hint. Since the calculated size hint is cached,
delete the cached value and call updateGeometry to cause a
recalculation.

Task-number: QTBUG-38949
Change-Id: I6e79e5e70e31afdfd129282b3668875eca86f51d
Reviewed-by: Marc Mutz <marc.mutz@kdab.com>

2 files changed, 32 insertions, 0 deletions

diff --git a/src/widgets/widgets/qtoolbutton.cpp b/src/widgets/widgets/qtoolbutton.cpp
index 497bc52109..cb441d6c6e 100644
--- a/src/widgets/widgets/qtoolbutton.cpp
+++ b/src/widgets/widgets/qtoolbutton.cpp
@@ -652,6 +652,10 @@ void QToolButton::setMenu(QMenu* menu)
     } else {
         d->menuAction = 0;
     }
+
+    // changing the menu set may change the size hint, so reset it
+    d->sizeHint = QSize();
+    updateGeometry();
     update();
 }
 
diff --git a/tests/auto/widgets/widgets/qtoolbutton/tst_qtoolbutton.cpp b/tests/auto/widgets/widgets/qtoolbutton/tst_qtoolbutton.cpp
index 168a17773e..650f189309 100644
--- a/tests/auto/widgets/widgets/qtoolbutton/tst_qtoolbutton.cpp
+++ b/tests/auto/widgets/widgets/qtoolbutton/tst_qtoolbutton.cpp
@@ -66,6 +66,7 @@ private slots:
     void task230994_iconSize();
     void task176137_autoRepeatOfAction();
     void qtbug_26956_popupTimerDone();
+    void qtbug_34759_sizeHintResetWhenSettingMenu();
 
 protected slots:
     void sendMouseClick();
@@ -265,5 +266,32 @@ void tst_QToolButton::qtbug_26956_popupTimerDone()
     tb->showMenu();
 }
 
+void tst_QToolButton::qtbug_34759_sizeHintResetWhenSettingMenu()
+{
+    // There is no reliable way of checking what's ultimately a style-dependent
+    // sizing. So the idea is checking if the size is the "correct" size w.r.t.
+    // another toolbutton which has had a menu set before it was shown for the first time
+
+    QToolButton button1;
+    QToolButton button2;
+
+    button1.setToolButtonStyle(Qt::ToolButtonIconOnly);
+    button1.setPopupMode(QToolButton::MenuButtonPopup);
+
+    button2.setToolButtonStyle(Qt::ToolButtonIconOnly);
+    button2.setPopupMode(QToolButton::MenuButtonPopup);
+
+    button2.setMenu(new QMenu(&button2));
+
+    button1.show();
+    button2.show();
+
+    QVERIFY(QTest::qWaitForWindowExposed(&button1));
+    QVERIFY(QTest::qWaitForWindowExposed(&button2));
+
+    button1.setMenu(new QMenu(&button1));
+    QTRY_COMPARE(button1.sizeHint(), button2.sizeHint());
+}
+
 QTEST_MAIN(tst_QToolButton)
 #include "tst_qtoolbutton.moc"