ComboBox: don't open on key release unless press was handled

If a Keys handler eats the press of the activation key, then the release
event shouldn't show the popup. The default keyPressEvent handler sets
the pressed state to true, so we can test that state to see if we should
act on the corresponding release. The key release event should still be
accepted to stop propagation.

Add a test case.

Pick-to: 6.5 6.2
Fixes: QTBUG-109721
Change-Id: Icb76453733d05cba59fdfb365b0cebf710be5f01
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>

src/quicktemplates/qquickcombobox.cpp

@@ -2064,7 +2064,7 @@ void QQuickComboBox::keyReleaseEvent(QKeyEvent *event)
     if (!isEditable()) {
         const auto buttonPressKeys = QGuiApplicationPrivate::platformTheme()->themeHint(QPlatformTheme::ButtonPressKeys).value<QList<Qt::Key>>();
         if (buttonPressKeys.contains(key)) {
-            if (!isEditable())
+            if (!isEditable() && isPressed())
                 d->togglePopup(true);
             setPressed(false);
             event->accept();

tests/auto/quickcontrols/controls/data/tst_combobox.qml

@@ -2277,6 +2277,35 @@ TestCase {
         compare(control.currentIndex, 1)
     }
 
+    // QTBUG-109721 - verify that an eaten press event for the space key
+    // doesn't open the popup when the key is released.
+    Component {
+        id: comboboxEatsSpace
+        ComboBox {
+            id: nonEditableComboBox
+            editable: false
+            model: ["NonEditable", "Delta", "Echo", "Foxtrot"]
+            Keys.onSpacePressed: (event) => event.accept
+        }
+    }
+
+    function test_spacePressEaten() {
+        let control = createTemporaryObject(comboboxEatsSpace, testCase)
+        verify(control)
+        control.forceActiveFocus()
+
+        var visibleChangedSpy = signalSpy.createObject(control, {target: control.popup, signalName: "visibleChanged"})
+        verify(visibleChangedSpy.valid)
+
+        // press doesn't open
+        keyPress(Qt.Key_Space)
+        verify(!control.pressed)
+        compare(visibleChangedSpy.count, 0)
+        // neither does release
+        keyRelease(Qt.Key_Space)
+        compare(visibleChangedSpy.count, 0)
+    }
+
     Component {
         id: listOfGadgets
         QtObject {