Add a Pragma for list assign behavior

[ChangeLog][QtQml] You can now specify the list property assignment
behavior in QML using the "ListPropertyAssignBehavior" pragma. This is
analogous to the macros you can use in C++.

Fixes: QTBUG-93642
Change-Id: I9bdcf198031f1e24891f947b0990a3253d29a998
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>

6 files changed, 174 insertions, 0 deletions

diff --git a/tests/auto/qml/qqmlproperty/data/listBehaviorAppendPragma.qml b/tests/auto/qml/qqmlproperty/data/listBehaviorAppendPragma.qml
new file mode 100644
index 0000000000..f7844564a8
--- /dev/null
+++ b/tests/auto/qml/qqmlproperty/data/listBehaviorAppendPragma.qml
@@ -0,0 +1,39 @@
+pragma ListPropertyAssignBehavior: Append
+
+import QtQml
+
+QtObject {
+    component WithDefault: QtObject {
+        default property list<QtObject> defaultList
+    }
+
+    component MyChild: WithDefault {
+        QtObject { objectName: "default1" }
+
+        property list<QtObject> myList: [
+            QtObject { objectName: "test1" }
+        ]
+    }
+
+    property MyChild myChild1: MyChild {
+        myList: [
+            QtObject { objectName: "test2" }
+        ]
+
+        QtObject { objectName: "default2" }
+    }
+
+    property MyChild myChild2: MyChild {
+        property list<QtObject> myOwnList: [
+            QtObject { property string str: "test3" }
+        ]
+        myList: myOwnList
+        defaultList: myOwnList
+    }
+
+    property int length1: myChild1.myList.length
+    property int length2: myChild2.myList.length
+
+    property int default1: myChild1.defaultList.length
+    property int default2: myChild2.defaultList.length
+}
diff --git a/tests/auto/qml/qqmlproperty/data/listBehaviorFail1.qml b/tests/auto/qml/qqmlproperty/data/listBehaviorFail1.qml
new file mode 100644
index 0000000000..2723249e48
--- /dev/null
+++ b/tests/auto/qml/qqmlproperty/data/listBehaviorFail1.qml
@@ -0,0 +1,3 @@
+pragma ListPropertyAssignBehavior: Foo
+import QtQml
+QtObject {}
diff --git a/tests/auto/qml/qqmlproperty/data/listBehaviorFail2.qml b/tests/auto/qml/qqmlproperty/data/listBehaviorFail2.qml
new file mode 100644
index 0000000000..63b79f85d1
--- /dev/null
+++ b/tests/auto/qml/qqmlproperty/data/listBehaviorFail2.qml
@@ -0,0 +1,5 @@
+pragma ListPropertyAssignBehavior: Append
+pragma Singleton
+pragma ListPropertyAssignBehavior: Replace
+import QtQml
+QtObject {}
diff --git a/tests/auto/qml/qqmlproperty/data/listBehaviorReplaceIfNotDefaultPragma.qml b/tests/auto/qml/qqmlproperty/data/listBehaviorReplaceIfNotDefaultPragma.qml
new file mode 100644
index 0000000000..ea4de1d8a4
--- /dev/null
+++ b/tests/auto/qml/qqmlproperty/data/listBehaviorReplaceIfNotDefaultPragma.qml
@@ -0,0 +1,39 @@
+pragma ListPropertyAssignBehavior: ReplaceIfNotDefault
+
+import QtQml
+
+QtObject {
+    component WithDefault: QtObject {
+        default property list<QtObject> defaultList
+    }
+
+    component MyChild: WithDefault {
+        QtObject { objectName: "default1" }
+
+        property list<QtObject> myList: [
+            QtObject { objectName: "test1" }
+        ]
+    }
+
+    property MyChild myChild1: MyChild {
+        myList: [
+            QtObject { objectName: "test2" }
+        ]
+
+        QtObject { objectName: "default2" }
+    }
+
+    property MyChild myChild2: MyChild {
+        property list<QtObject> myOwnList: [
+            QtObject { property string str: "test3" }
+        ]
+        myList: myOwnList
+        defaultList: myOwnList
+    }
+
+    property int length1: myChild1.myList.length
+    property int length2: myChild2.myList.length
+
+    property int default1: myChild1.defaultList.length
+    property int default2: myChild2.defaultList.length
+}
diff --git a/tests/auto/qml/qqmlproperty/data/listBehaviorReplacePragma.qml b/tests/auto/qml/qqmlproperty/data/listBehaviorReplacePragma.qml
new file mode 100644
index 0000000000..e960a7cac5
--- /dev/null
+++ b/tests/auto/qml/qqmlproperty/data/listBehaviorReplacePragma.qml
@@ -0,0 +1,39 @@
+pragma ListPropertyAssignBehavior: Replace
+
+import QtQml
+
+QtObject {
+    component WithDefault: QtObject {
+        default property list<QtObject> defaultList
+    }
+
+    component MyChild: WithDefault {
+        QtObject { objectName: "default1" }
+
+        property list<QtObject> myList: [
+            QtObject { objectName: "test1" }
+        ]
+    }
+
+    property MyChild myChild1: MyChild {
+        myList: [
+            QtObject { objectName: "test2" }
+        ]
+
+        QtObject { objectName: "default2" }
+    }
+
+    property MyChild myChild2: MyChild {
+        property list<QtObject> myOwnList: [
+            QtObject { property string str: "test3" }
+        ]
+        myList: myOwnList
+        defaultList: myOwnList
+    }
+
+    property int length1: myChild1.myList.length
+    property int length2: myChild2.myList.length
+
+    property int default1: myChild1.defaultList.length
+    property int default2: myChild2.defaultList.length
+}
diff --git a/tests/auto/qml/qqmlproperty/tst_qqmlproperty.cpp b/tests/auto/qml/qqmlproperty/tst_qqmlproperty.cpp
index fc045b777c..9cf622c2d7 100644
--- a/tests/auto/qml/qqmlproperty/tst_qqmlproperty.cpp
+++ b/tests/auto/qml/qqmlproperty/tst_qqmlproperty.cpp
@@ -1724,6 +1724,55 @@ void tst_qqmlproperty::listOverrideBehavior()
     QVERIFY(alwaysReplaceContainer != nullptr);
     QQmlListReference alwaysReplaceChildrenList(alwaysReplaceContainer, "children");
     QCOMPARE(alwaysReplaceChildrenList.count(), 2);
+
+    {
+        QQmlComponent appendQml(&engine, testFileUrl("listBehaviorAppendPragma.qml"));
+        QVERIFY2(appendQml.isReady(), qPrintable(appendQml.errorString()));
+        QScopedPointer<QObject> o(appendQml.create());
+        QVERIFY(o);
+        QCOMPARE(o->property("length1").toInt(), 2);
+        QCOMPARE(o->property("length2").toInt(), 1);
+        QCOMPARE(o->property("default1").toInt(), 2);
+        QCOMPARE(o->property("default2").toInt(), 1);
+    }
+
+    {
+        QQmlComponent replaceQml(&engine, testFileUrl("listBehaviorReplacePragma.qml"));
+        QVERIFY2(replaceQml.isReady(), qPrintable(replaceQml.errorString()));
+        QScopedPointer<QObject> o(replaceQml.create());
+        QVERIFY(o);
+        QCOMPARE(o->property("length1").toInt(), 1);
+        QCOMPARE(o->property("length2").toInt(), 1);
+        QCOMPARE(o->property("default1").toInt(), 1);
+        QCOMPARE(o->property("default2").toInt(), 1);
+    }
+
+    {
+        QQmlComponent replaceIfNotDefaultQml(
+                    &engine, testFileUrl("listBehaviorReplaceIfNotDefaultPragma.qml"));
+        QVERIFY2(replaceIfNotDefaultQml.isReady(),
+                 qPrintable(replaceIfNotDefaultQml.errorString()));
+        QScopedPointer<QObject> o(replaceIfNotDefaultQml.create());
+        QVERIFY(o);
+        QCOMPARE(o->property("length1").toInt(), 1);
+        QCOMPARE(o->property("length2").toInt(), 1);
+        QCOMPARE(o->property("default1").toInt(), 2);
+        QCOMPARE(o->property("default2").toInt(), 1);
+    }
+
+    {
+        QQmlComponent fail1(&engine, testFileUrl("listBehaviorFail1.qml"));
+        QVERIFY(fail1.isError());
+        QVERIFY(fail1.errorString().contains(
+                 QStringLiteral("Unknown list property assign behavior 'Foo' in pragma")));
+    }
+
+    {
+        QQmlComponent fail2(&engine, testFileUrl("listBehaviorFail2.qml"));
+        QVERIFY(fail2.isError());
+        QVERIFY(fail2.errorString().contains(
+                 QStringLiteral("Multiple list property assign behavior pragmas found")));
+    }
 }
 
 void tst_qqmlproperty::urlHandling_data()