Fix QQmlProperty and Connections for properties starting with '_'

We do a weird renaming for the change handler of properties starting
with '_', now we do it at least in a consistent way.

Fixes: QTBUG-82017
Change-Id: I1535a5ee462f3a344c972461f1fb954f039aa854
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

3 files changed, 49 insertions, 0 deletions

diff --git a/tests/auto/qml/qqmlconnections/data/underscore.qml b/tests/auto/qml/qqmlconnections/data/underscore.qml
new file mode 100644
index 0000000000..0f73dc8f17
--- /dev/null
+++ b/tests/auto/qml/qqmlconnections/data/underscore.qml
@@ -0,0 +1,14 @@
+import QtQuick 2.12
+
+Item {
+    id: item
+    property bool success: false
+    property bool sanityCheck: false
+    property int __underscore_property: 0
+    on__Underscore_propertyChanged: item.sanityCheck = true
+
+    Connections {
+        target: item
+        on__Underscore_propertyChanged: item.success = true
+    }
+}
diff --git a/tests/auto/qml/qqmlconnections/tst_qqmlconnections.cpp b/tests/auto/qml/qqmlconnections/tst_qqmlconnections.cpp
index 07af519a3d..f144002875 100644
--- a/tests/auto/qml/qqmlconnections/tst_qqmlconnections.cpp
+++ b/tests/auto/qml/qqmlconnections/tst_qqmlconnections.cpp
@@ -77,6 +77,8 @@ private slots:
     void noAcceleratedGlobalLookup_data() { prefixes(); }
     void noAcceleratedGlobalLookup();
 
+    void bindToPropertyWithUnderscoreChangeHandler();
+
 private:
     QQmlEngine engine;
     void prefixes();
@@ -474,6 +476,19 @@ void tst_qqmlconnections::noAcceleratedGlobalLookup()
     QCOMPARE(val.toInt(), int(Proxy::EnumValue));
 }
 
+void tst_qqmlconnections::bindToPropertyWithUnderscoreChangeHandler()
+{
+    QQmlEngine engine;
+    QQmlComponent component(&engine, testFileUrl("underscore.qml"));
+    QScopedPointer<QObject> root {component.create()};
+    QVERIFY(root);
+    QQmlProperty underscoreProperty(root.get(), "__underscore_property");
+    QVERIFY(underscoreProperty.isValid());
+    underscoreProperty.write(42);
+    QVERIFY(root->property("sanityCheck").toBool());
+    QVERIFY(root->property("success").toBool());
+}
+
 QTEST_MAIN(tst_qqmlconnections)
 
 #include "tst_qqmlconnections.moc"
diff --git a/tests/auto/qml/qqmlproperty/tst_qqmlproperty.cpp b/tests/auto/qml/qqmlproperty/tst_qqmlproperty.cpp
index a15c00ad62..864a47e998 100644
--- a/tests/auto/qml/qqmlproperty/tst_qqmlproperty.cpp
+++ b/tests/auto/qml/qqmlproperty/tst_qqmlproperty.cpp
@@ -158,6 +158,8 @@ private slots:
     void copy();
 
     void nestedQQmlPropertyMap();
+
+    void underscorePropertyChangeHandler();
 private:
     QQmlEngine engine;
 };
@@ -2230,6 +2232,24 @@ void tst_qqmlproperty::nestedQQmlPropertyMap()
     QCOMPARE(success.read().toString(), QLatin1String("success"));
 }
 
+void tst_qqmlproperty::underscorePropertyChangeHandler()
+{
+    QQmlEngine engine;
+    QQmlComponent component(&engine);
+    component.setData(R"(
+        import QtQuick 2.12
+
+        Item {
+            property int __withUnderScore
+        }
+    )", QUrl::fromLocalFile("."));
+    QScopedPointer<QObject> root { component.create() };
+    QVERIFY(root);
+    QQmlProperty changeHandler(root.get(), "on__WithUnderScoreChanged");
+    QVERIFY(changeHandler.isValid());
+    QVERIFY(changeHandler.isSignalProperty());
+}
+
 QTEST_MAIN(tst_qqmlproperty)
 
 #include "tst_qqmlproperty.moc"