qqmlengine: Fix crash when encountering bad singletons

Previously errors occurring when parsing QML singletons would just be ignored resulting in a crash.
The errors are now properly printed and the execution is aborted in time.

Fixes: QTBUG-85932
Change-Id: I61cef5f97546ce2e0753bc46c548838a21b1f506
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>

4 files changed, 43 insertions, 0 deletions

diff --git a/tests/auto/qml/qqmllanguage/data/SingletonTest.qml b/tests/auto/qml/qqmllanguage/data/SingletonTest.qml
new file mode 100644
index 0000000000..70e1671754
--- /dev/null
+++ b/tests/auto/qml/qqmllanguage/data/SingletonTest.qml
@@ -0,0 +1,14 @@
+pragma Singleton
+
+import QtQml 2.0
+
+// This causes a duplicate id error on purpose
+QtObject {
+    id: foo
+
+    QtObject {
+        id: foo
+    }
+
+    function test() { return "Foobar"; }
+}
diff --git a/tests/auto/qml/qqmllanguage/data/qmldir b/tests/auto/qml/qqmllanguage/data/qmldir
new file mode 100644
index 0000000000..c946de657c
--- /dev/null
+++ b/tests/auto/qml/qqmllanguage/data/qmldir
@@ -0,0 +1,2 @@
+singleton SingletonTest 1.0 SingletonTest.qml
+
diff --git a/tests/auto/qml/qqmllanguage/data/qtbug_85932.qml b/tests/auto/qml/qqmllanguage/data/qtbug_85932.qml
new file mode 100644
index 0000000000..aa21558220
--- /dev/null
+++ b/tests/auto/qml/qqmllanguage/data/qtbug_85932.qml
@@ -0,0 +1,5 @@
+import QtQml 2.0
+
+QtObject {
+    Component.onCompleted: console.log(SingletonTest.test())
+}
diff --git a/tests/auto/qml/qqmllanguage/tst_qqmllanguage.cpp b/tests/auto/qml/qqmllanguage/tst_qqmllanguage.cpp
index 448ecaa5b3..4f4ee45f68 100644
--- a/tests/auto/qml/qqmllanguage/tst_qqmllanguage.cpp
+++ b/tests/auto/qml/qqmllanguage/tst_qqmllanguage.cpp
@@ -344,6 +344,7 @@ private slots:
     void extendedNamespace();
     void factorySingleton();
     void extendedSingleton();
+    void qtbug_85932();
 
 private:
     QQmlEngine engine;
@@ -6095,6 +6096,27 @@ void tst_qqmllanguage::extendedSingleton()
     QCOMPARE(obj->property("d").toInt(), 9);
 }
 
+void tst_qqmllanguage::qtbug_85932()
+{
+    QString warning1 = QLatin1String("%1:10:9: id is not unique").arg(testFileUrl("SingletonTest.qml").toString());
+    QString warning2 = QLatin1String("%1:4: Error: Due to the preceding error(s), Singleton \"SingletonTest\" could not be loaded.").arg(testFileUrl("qtbug_85932.qml").toString());
+
+    QTest::ignoreMessage(QtMsgType::QtWarningMsg, qPrintable(warning1));
+    QTest::ignoreMessage(QtMsgType::QtWarningMsg, qPrintable(warning2));
+
+    QQmlEngine engine;
+    QList<QQmlError> allWarnings;
+    QObject::connect(&engine, &QQmlEngine::warnings, [&allWarnings](const QList<QQmlError> &warnings) {
+        allWarnings.append(warnings);
+    });
+
+    QQmlComponent c(&engine, testFileUrl("qtbug_85932.qml"));
+    QScopedPointer<QObject> obj(c.create());
+    QTRY_COMPARE(allWarnings.count(), 2);
+    QCOMPARE(allWarnings.at(0).toString(), warning1);
+    QCOMPARE(allWarnings.at(1).toString(), warning2);
+}
+
 QTEST_MAIN(tst_qqmllanguage)
 
 #include "tst_qqmllanguage.moc"