Fix value-type semantics in variant properties

Previously, variant properties storing value-type values would be
treated as value-type-copy values rather than value-type-reference
values.  This caused inconsistency in behaviour with value-type
subproperty assignment.

Task-number: QTBUG-26562
Change-Id: I524ee06ab8e02bf9582c1a88f3317278199225e0
Reviewed-by: Martin Jones <martin.jones@nokia.com>

3 files changed, 87 insertions, 0 deletions

diff --git a/tests/auto/qml/qqmlvaluetypes/data/variant_write.1.qml b/tests/auto/qml/qqmlvaluetypes/data/variant_write.1.qml
new file mode 100644
index 0000000000..6063917dd4
--- /dev/null
+++ b/tests/auto/qml/qqmlvaluetypes/data/variant_write.1.qml
@@ -0,0 +1,25 @@
+import QtQuick 2.0
+
+Item {
+    property bool complete: false
+    property bool success: false
+
+    property variant v1: Qt.vector3d(1,2,3)
+    property variant v2: Qt.vector3d(4,5,6)
+    property variant v3: v1.plus(v2) // set up doomed binding
+
+    Component.onCompleted: {
+        complete = false;
+        success = true;
+
+        v1 = Qt.vector2d(1,2) // changing the type of the property shouldn't cause crash
+
+        v1.x = 8;
+        v2.x = 9;
+
+        if (v1 != Qt.vector2d(8,2)) success = false;
+        if (v2 != Qt.vector3d(9,5,6)) success = false;
+
+        complete = true;
+    }
+}
diff --git a/tests/auto/qml/qqmlvaluetypes/data/variant_write.2.qml b/tests/auto/qml/qqmlvaluetypes/data/variant_write.2.qml
new file mode 100644
index 0000000000..0dbfd2a012
--- /dev/null
+++ b/tests/auto/qml/qqmlvaluetypes/data/variant_write.2.qml
@@ -0,0 +1,40 @@
+import QtQuick 2.0
+
+Item {
+    property bool complete: false
+    property bool success: false
+
+    property variant v1
+
+    Component.onCompleted: {
+        complete = false;
+        success = true;
+
+        // store a js reference to the VariantReference vt in a temp var.
+        v1 = Qt.vector3d(1,2,3)
+        var ref = v1;
+        ref.z = 5
+        if (v1 != Qt.vector3d(1,2,5)) success = false;
+
+        // now change the type of a reference, and attempt a valid write.
+        v1 = Qt.vector2d(1,2);
+        ref.x = 5;
+        if (v1 != Qt.vector2d(5,2)) success = false;
+
+        // now change the type of a reference, and attempt an invalid write.
+        v1 = Qt.rgba(1,0,0,1);
+        ref.x = 5;
+        if (v1.toString() != Qt.rgba(1,0,0,1).toString()) success = false;
+        v1 = 6;
+        ref.x = 5;
+        if (v1 != 6) success = false;
+
+        // now change the type of a reference, and attempt an invalid read.
+        v1 = Qt.vector3d(1,2,3);
+        ref = v1;
+        v1 = Qt.vector2d(1,2);
+        if (ref.z == 3) success = false;
+
+        complete = true;
+    }
+}
diff --git a/tests/auto/qml/qqmlvaluetypes/tst_qqmlvaluetypes.cpp b/tests/auto/qml/qqmlvaluetypes/tst_qqmlvaluetypes.cpp
index af5e914290..a323db5d5f 100644
--- a/tests/auto/qml/qqmlvaluetypes/tst_qqmlvaluetypes.cpp
+++ b/tests/auto/qml/qqmlvaluetypes/tst_qqmlvaluetypes.cpp
@@ -290,6 +290,7 @@ void tst_qqmlvaluetypes::sizef()
 
 void tst_qqmlvaluetypes::variant()
 {
+    {
     QQmlComponent component(&engine, testFileUrl("variant_read.qml"));
     MyTypeObject *object = qobject_cast<MyTypeObject *>(component.create());
     QVERIFY(object != 0);
@@ -299,6 +300,27 @@ void tst_qqmlvaluetypes::variant()
     QCOMPARE(object->property("copy"), QVariant(QSizeF(0.1, 100923.2)));
 
     delete object;
+    }
+
+    {
+    QString w1 = testFileUrl("variant_write.1.qml").toString() + QLatin1String(":9: TypeError: Object QVector2D(8, 2) has no method 'plus'");
+    QTest::ignoreMessage(QtWarningMsg, qPrintable(w1));
+    QQmlComponent component(&engine, testFileUrl("variant_write.1.qml"));
+    QObject *object = component.create();
+    QVERIFY(object != 0);
+    QVERIFY(object->property("complete").toBool());
+    QVERIFY(object->property("success").toBool());
+    delete object;
+    }
+
+    {
+    QQmlComponent component(&engine, testFileUrl("variant_write.2.qml"));
+    QObject *object = component.create();
+    QVERIFY(object != 0);
+    QVERIFY(object->property("complete").toBool());
+    QVERIFY(object->property("success").toBool());
+    delete object;
+    }
 }
 
 void tst_qqmlvaluetypes::sizereadonly()