Fix deferred execution

If the QML engine refuses to defer execution of a delegate (it contains
an ID), we must make sure to cancel any pending deferred execution for
the same delegate. Otherwise, we may end up overriding a custom (non-
deferred) delegate with a default (deferred) delegate.

This patch adds a new test style "identified" to tst_customization.
This style contains delegates with IDs so we can test the behavior with
IDs in base styles. Furthermore, overriding delegates is now tested
in various ways (with and without IDs in the base and custom styles) in
a separate test method. This is done by generating QML code to override
delegates with dummy Item instances with appropriate IDs and names.

Task-number: QTBUG-65341
Change-Id: Ie6dca287cb74672004d9d8f599760b9d32c3a380
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>

1 files changed, 11 insertions, 1 deletions

diff --git a/src/quicktemplates2/qquickgroupbox.cpp b/src/quicktemplates2/qquickgroupbox.cpp
index 674f5b18..3c7bf715 100644
--- a/src/quicktemplates2/qquickgroupbox.cpp
+++ b/src/quicktemplates2/qquickgroupbox.cpp
@@ -91,6 +91,7 @@ class QQuickGroupBoxPrivate : public QQuickFramePrivate
 public:
     QQuickGroupBoxPrivate() : label(nullptr) { }
 
+    void cancelLabel();
     void executeLabel(bool complete = false);
 
     QString title;
@@ -99,13 +100,19 @@ public:
 
 static inline QString labelName() { return QStringLiteral("label"); }
 
+void QQuickGroupBoxPrivate::cancelLabel()
+{
+    Q_Q(QQuickGroupBox);
+    quickCancelDeferred(q, labelName());
+}
+
 void QQuickGroupBoxPrivate::executeLabel(bool complete)
 {
     Q_Q(QQuickGroupBox);
     if (label.wasExecuted())
         return;
 
-    if (!label)
+    if (!label || complete)
         quickBeginDeferred(q, labelName(), label);
     if (complete)
         quickCompleteDeferred(q, labelName(), label);
@@ -162,6 +169,9 @@ void QQuickGroupBox::setLabel(QQuickItem *label)
     if (d->label == label)
         return;
 
+    if (!d->label.isExecuting())
+        d->cancelLabel();
+
     delete d->label;
     d->label = label;
     if (label && !label->parentItem())