Account for QPolygonF type when loading/saving the QVariant

When the QPolygonF type was added to QMetaType it did not bump up the
values in load() and save() for QVariant.

Task-number: QTBUG-33981

Change-Id: I7ad99cda70620c5449c15527c3daf920972d047f
Reviewed-by: Jędrzej Nowacki <jedrzej.nowacki@digia.com>
Reviewed-by: Stephen Kelly <stephen.kelly@kdab.com>

src/corelib/kernel/qvariant.cpp

@@ -1892,6 +1892,7 @@ void QVariant::load(QDataStream &s)
 void QVariant::save(QDataStream &s) const
 {
     quint32 typeId = type();
+    bool fakeUserType = false;
     if (s.version() < QDataStream::Qt_4_0) {
         int i;
         for (i = 0; i <= MapFromThreeCount - 1; ++i) {
@@ -1916,12 +1917,16 @@ void QVariant::save(QDataStream &s) const
         } else if (typeId >= QMetaType::QKeySequence && typeId <= QMetaType::QQuaternion) {
             // and as a result these types received lower ids too
             typeId +=1;
+        } else if (typeId == QMetaType::QPolygonF) {
+            // This existed in Qt 4 only as a custom type
+            typeId = 127;
+            fakeUserType = true;
         }
     }
     s << typeId;
     if (s.version() >= QDataStream::Qt_4_2)
         s << qint8(d.is_null);
-    if (d.type >= QVariant::UserType) {
+    if (d.type >= QVariant::UserType || fakeUserType) {
         s << QMetaType::typeName(userType());
     }
 

tests/auto/gui/kernel/qguivariant/test/qguivariant.qrc

@@ -0,0 +1,5 @@
+<!DOCTYPE RCC><RCC version="1.0">
+<qresource>
+    <file>data</file>
+</qresource>
+</RCC>

tests/auto/gui/kernel/qguivariant/test/test.pro

@@ -4,3 +4,4 @@ TARGET = tst_qguivariant
 SOURCES  += tst_qguivariant.cpp
 INCLUDEPATH += $$PWD/../../../../other/qvariant_common
 QT += testlib
+RESOURCES += qguivariant.qrc

tests/auto/gui/kernel/qguivariant/test/tst_qguivariant.cpp

@@ -114,6 +114,7 @@ private slots:
 
     void writeToReadFromDataStream_data();
     void writeToReadFromDataStream();
+    void writeToReadFromOldDataStream();
 
     void colorInteger();
     void invalidQColor();
@@ -525,6 +526,7 @@ void tst_QGuiVariant::writeToReadFromDataStream_data()
     QTest::newRow( "pointarray_valid" ) << QVariant::fromValue( QPolygon( QRect( 10, 10, 20, 20 ) ) ) << false;
     QTest::newRow( "region_invalid" ) << QVariant::fromValue( QRegion() ) << true;
     QTest::newRow( "region_valid" ) << QVariant::fromValue( QRegion( 10, 10, 20, 20 ) ) << false;
+    QTest::newRow("polygonf_valid") << QVariant::fromValue(QPolygonF(QRectF(10, 10, 20, 20))) << false;
 }
 
 void tst_QGuiVariant::invalidQColor()
@@ -609,6 +611,46 @@ void tst_QGuiVariant::writeToReadFromDataStream()
     }
 }
 
+void tst_QGuiVariant::writeToReadFromOldDataStream()
+{
+    QPolygonF polyF(QRectF(10, 10, 50, 50));
+    QVariant testVariant(polyF);
+    {
+        // Read into a variant and compare
+        QFile file(":/data/qpolygonf.bin");
+        QVERIFY(file.open(QIODevice::ReadOnly));
+        QDataStream dataFileStream(&file);
+        dataFileStream.setVersion(QDataStream::Qt_4_9);
+        QVariant readVariant;
+        dataFileStream >> readVariant;
+        QVERIFY(readVariant.type() == QMetaType::QPolygonF);
+        QCOMPARE(testVariant, readVariant);
+        file.close();
+    }
+    {
+        QByteArray variantData;
+        {
+            QDataStream varDataStream(&variantData, QIODevice::WriteOnly);
+            varDataStream << testVariant;
+        }
+        // Read into a bytearray and compare
+        QFile file(":/data/qpolygonf.bin");
+        QVERIFY(file.open(QIODevice::ReadOnly));
+        QDataStream dataFileStream(&file);
+        dataFileStream.setVersion(QDataStream::Qt_4_9);
+        int dummy;
+        dataFileStream >> dummy;
+        QByteArray polyData49;
+        dataFileStream >> polyData49;
+        file.close();
+        QByteArray polyData50;
+        QDataStream readVarData(variantData);
+        readVarData >> dummy;
+        readVarData >> polyData50;
+        QVERIFY(polyData49 == polyData50);
+    }
+}
+
 void tst_QGuiVariant::debugStream_data()
 {
     QTest::addColumn<QVariant>("variant");