Print function identifier when calling toString() on a function

Task-number: QTBUG-50669
Change-Id: Ia0e9491b12ca1db1da2bfa8eb5ca8bbe4658f699
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

3 files changed, 41 insertions, 2 deletions

diff --git a/src/qml/jsruntime/qv4functionobject.cpp b/src/qml/jsruntime/qv4functionobject.cpp
index 8a70715728..1eb56b9c2a 100644
--- a/src/qml/jsruntime/qv4functionobject.cpp
+++ b/src/qml/jsruntime/qv4functionobject.cpp
@@ -311,7 +311,19 @@ ReturnedValue FunctionPrototype::method_toString(const FunctionObject *b, const
     if (!fun)
         return v4->throwTypeError();
 
-    return Encode(v4->newString(QStringLiteral("function() { [code] }")));
+    const Scope scope(fun->engine());
+    const ScopedString scopedFunctionName(scope, fun->name());
+    const QString functionName(scopedFunctionName ? scopedFunctionName->toQString() : QString());
+    QString functionAsString = QStringLiteral("function");
+
+    // If fun->name() is empty, then there is no function name
+    // to append because the function is anonymous.
+    if (!functionName.isEmpty())
+        functionAsString.append(QLatin1Char(' ') + functionName);
+
+    functionAsString.append(QStringLiteral("() { [code] }"));
+
+    return Encode(v4->newString(functionAsString));
 }
 
 ReturnedValue FunctionPrototype::method_apply(const QV4::FunctionObject *b, const Value *thisObject, const Value *argv, int argc)
diff --git a/tests/auto/qml/qjsengine/tst_qjsengine.cpp b/tests/auto/qml/qjsengine/tst_qjsengine.cpp
index 85b4484403..911da1b20c 100644
--- a/tests/auto/qml/qjsengine/tst_qjsengine.cpp
+++ b/tests/auto/qml/qjsengine/tst_qjsengine.cpp
@@ -212,6 +212,9 @@ private slots:
 
     void deleteInsideForIn();
 
+    void functionToString_data();
+    void functionToString();
+
 signals:
     void testSignal();
 };
@@ -4220,6 +4223,30 @@ void tst_QJSEngine::deleteInsideForIn()
     QCOMPARE(iterationCount.toInt(), 4);
 }
 
+void tst_QJSEngine::functionToString_data()
+{
+    QTest::addColumn<QString>("source");
+    QTest::addColumn<QString>("expectedString");
+
+    QTest::newRow("named function") << QString::fromLatin1("function f() {}; f.toString()")
+        << QString::fromLatin1("function f() { [code] }");
+    QTest::newRow("anonymous function") << QString::fromLatin1("(function() {}).toString()")
+        << QString::fromLatin1("function() { [code] }");
+}
+
+// Tests that function.toString() prints the function's name.
+void tst_QJSEngine::functionToString()
+{
+    QFETCH(QString, source);
+    QFETCH(QString, expectedString);
+
+    QJSEngine engine;
+    engine.installExtensions(QJSEngine::AllExtensions);
+    QJSValue evaluationResult = engine.evaluate(source);
+    QVERIFY(!evaluationResult.isError());
+    QCOMPARE(evaluationResult.toString(), expectedString);
+}
+
 QTEST_MAIN(tst_QJSEngine)
 
 #include "tst_qjsengine.moc"
diff --git a/tests/auto/qml/qqmlconsole/tst_qqmlconsole.cpp b/tests/auto/qml/qqmlconsole/tst_qqmlconsole.cpp
index 5391e19f50..40a9295e50 100644
--- a/tests/auto/qml/qqmlconsole/tst_qqmlconsole.cpp
+++ b/tests/auto/qml/qqmlconsole/tst_qqmlconsole.cpp
@@ -75,7 +75,7 @@ void tst_qqmlconsole::logging()
     QTest::ignoreMessage(QtDebugMsg, "{\"a\":\"hello\",\"d\":1}");
     QTest::ignoreMessage(QtDebugMsg, "undefined");
     QTest::ignoreMessage(QtDebugMsg, "12");
-    QTest::ignoreMessage(QtDebugMsg, "function() { [code] }");
+    QTest::ignoreMessage(QtDebugMsg, "function e() { [code] }");
     QTest::ignoreMessage(QtDebugMsg, "true");
     // Printing QML object prints out the class/type of QML object with the memory address
 //    QTest::ignoreMessage(QtDebugMsg, "QtObject_QML_0(0xABCD..)");