Popup: ensure that "palette" is reevaluated when enabled state changes

When changing the enabled state of a Menu after component completion,
the background would not change. The problem was that
QQuickPopup::paletteChanged() was not being emitted when the enabled
state changed, resulting in QQuickControl::palette() (which
QQuickPopup::palette() forwards calls to via its popupItem) not
being called. QQuickControl::palette() changes the palette's current
color group to QPalette::Disabled when it is disabled, so if it's not
called, the popup's colors won't change.

Fix the issue by adding a virtual enabledChange() function to
QQuickControl, which QQuickPopupItem can override to emit both
QQuickPopup::enabledChanged() (saving a connection in the process)
and QQuickPopup::paletteChanged(). This ensures that bindings to
QQuickPopup::palette are re-evaluated.

The patch adds a virtual instead of just emitting paletteChanged()
in QQuickPopup::setEnabled(), because we also want to be notified
of indirect enabled state changes, such as those coming from
parent items.

Change-Id: Ibdbd05f27b5a74fe731bda9d6698cbf6b8f81785
Fixes: QTBUG-73447
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@qt.io>

1 files changed, 72 insertions, 0 deletions

diff --git a/tests/auto/qquickpopup/data/disabledPalette.qml b/tests/auto/qquickpopup/data/disabledPalette.qml
new file mode 100644
index 00000000..f080f5e8
--- /dev/null
+++ b/tests/auto/qquickpopup/data/disabledPalette.qml
@@ -0,0 +1,72 @@
+/****************************************************************************
+**
+** Copyright (C) 2019 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the test suite of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
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+**
+** BSD License Usage
+** Alternatively, you may use this file under the terms of the BSD license
+** as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
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+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+import QtQuick 2.12
+import QtQuick.Controls 2.12
+
+ApplicationWindow {
+    width: 400
+    height: 400
+
+    property alias popup: popup
+
+    function disableOverlay() {
+        popup.Overlay.overlay.enabled = false
+    }
+
+    Popup {
+        id: popup
+        width: 200
+        height: 200
+        background: Rectangle {
+            color: popup.palette.base
+        }
+    }
+}