QCocoaMenu: Force NSMenuValidation when syncing items

When a menu item's enabled state changes after
-[QCocoaMenuDelegate menuWillOpen:] is invoked, i.e.,
during or after QMenu::aboutToShow() is emitted, that
state change may not be taken into account. This is
because the automatic menu validation, upon which Qt
relies, is not made aware of any such change.

By calling -[NSMenu update] when syncing the QPA menu
item, we induce Cocoa to invoke -[QCocoaMenuDelegate
validateMenuItem:] and ensure that previously synced
items, whose state may have changed, will be properly
updated. This, however, has a small side effect, namely
that menu-holding items will also go through the automatic
menu enabling path and may appear disabled since, until
now, they were not properly configured. In order to solve
this, we set the action on those items as well, and make
sure that both of QCocoaMenuDelegate's relevant methods,
validateMenuItem: and itemFired:, properly process
menu-holding items.

Menurama manual test updated accordingly.

Change-Id: I62f955538b8be09b8494ea0ce87fca7910148d38
Task-number: QTBUG-56850
Reviewed-by: Timur Pocheptsov <timur.pocheptsov@qt.io>

1 files changed, 13 insertions, 4 deletions

diff --git a/src/plugins/platforms/cocoa/qcocoamenu.mm b/src/plugins/platforms/cocoa/qcocoamenu.mm
index 566363e01f..88ffd48538 100644
--- a/src/plugins/platforms/cocoa/qcocoamenu.mm
+++ b/src/plugins/platforms/cocoa/qcocoamenu.mm
@@ -147,6 +147,10 @@ QT_NAMESPACE_ALIAS_OBJC_CLASS(QCocoaMenuDelegate);
 - (void) itemFired:(NSMenuItem*) item
 {
     QCocoaMenuItem *cocoaItem = reinterpret_cast<QCocoaMenuItem *>([item tag]);
+    // Menu-holding items also get a target to play nicely
+    // with NSMenuValidation but should not trigger.
+    if (cocoaItem->menu())
+        return;
     QScopedScopeLevelCounter scopeLevelCounter(QGuiApplicationPrivate::instance()->threadData);
     QGuiApplicationPrivate::modifier_buttons = [QNSView convertKeyModifiers:[NSEvent modifierFlags]];
     static QMetaMethod activatedSignal = QMetaMethod::fromSignal(&QCocoaMenuItem::activated);
@@ -156,7 +160,8 @@ QT_NAMESPACE_ALIAS_OBJC_CLASS(QCocoaMenuDelegate);
 - (BOOL)validateMenuItem:(NSMenuItem*)menuItem
 {
     QCocoaMenuItem *cocoaItem = reinterpret_cast<QCocoaMenuItem *>(menuItem.tag);
-    if (!cocoaItem)
+    // Menu-holding items are always enabled, as it's conventional in Cocoa
+    if (!cocoaItem || cocoaItem->menu())
         return YES;
 
     return cocoaItem->isEnabled();
@@ -327,9 +332,9 @@ void QCocoaMenu::insertMenuItem(QPlatformMenuItem *menuItem, QPlatformMenuItem *
 void QCocoaMenu::insertNative(QCocoaMenuItem *item, QCocoaMenuItem *beforeItem)
 {
     item->nsItem().target = m_nativeMenu.delegate;
-    if (!item->menu())
-        [item->nsItem() setAction:@selector(itemFired:)];
-    else if (isOpen() && item->nsItem()) // Someone's adding new items after aboutToShow() was emitted
+    item->nsItem().action = @selector(itemFired:);
+    // Someone's adding new items after aboutToShow() was emitted
+    if (isOpen() && item->menu() && item->nsItem())
         item->menu()->setAttachedItem(item->nsItem());
 
     item->setParentEnabled(isEnabled());
@@ -425,6 +430,10 @@ void QCocoaMenu::syncMenuItem(QPlatformMenuItem *menuItem)
 
         QCocoaMenuItem* beforeItem = itemOrNull(m_menuItems.indexOf(cocoaItem) + 1);
         insertNative(cocoaItem, beforeItem);
+    } else {
+        // Force NSMenuValidation to kick in. This is needed e.g.
+        // when an item's enabled state changes after menuWillOpen:
+        [m_nativeMenu update];
     }
 }