Fix mapping of JS objects/arrays to C++

[ChangeLog][QtQml][Important Behavior Changes] When a JavaScript object/array
is passed to C++ through a QVariant, the engine no longer immediately converts
the object recursively into a QVariantMap or QVariantList but instead stores
a QJSValue in the QVariant. This prevents a loss of data when the JS object
contains non-primitive types such as function objects for example. Code that
expects the variant type to be exactly QVariant::Map or QVariant::List may
need to be adapted. Registered conversion functions however ensure that code
that merely calls toMap() or toList() continues to work.

Task-number: QTBUG-40431
Change-Id: I1dbc1d5f8e78ad28bb62db3681b9a0b34557e7f5
Reviewed-by: Lars Knoll <lars.knoll@digia.com>

1 files changed, 44 insertions, 6 deletions

diff --git a/tests/auto/qml/qjsvalue/tst_qjsvalue.cpp b/tests/auto/qml/qjsvalue/tst_qjsvalue.cpp
index 837403d391..9c615cfc15 100644
--- a/tests/auto/qml/qjsvalue/tst_qjsvalue.cpp
+++ b/tests/auto/qml/qjsvalue/tst_qjsvalue.cpp
@@ -34,10 +34,6 @@
 #include "tst_qjsvalue.h"
 #include <QtWidgets/QPushButton>
 
-QT_BEGIN_NAMESPACE
-extern bool qt_script_isJITEnabled();
-QT_END_NAMESPACE
-
 tst_QJSValue::tst_QJSValue()
     : engine(0)
 {
@@ -45,8 +41,7 @@ tst_QJSValue::tst_QJSValue()
 
 tst_QJSValue::~tst_QJSValue()
 {
-    if (engine)
-        delete engine;
+    delete engine;
 }
 
 void tst_QJSValue::ctor_invalid()
@@ -308,6 +303,19 @@ void tst_QJSValue::ctor_copyAndAssign()
     QCOMPARE(v5.toNumber(), 1.0);
 }
 
+static QJSValue createUnboundValue(const QJSValue &value)
+{
+    QVariant variant = QVariant::fromValue(value);
+    QBuffer buffer;
+    buffer.open(QIODevice::ReadWrite);
+    QDataStream stream(&buffer);
+    variant.save(stream);
+    buffer.seek(0);
+    QVariant resultVariant;
+    resultVariant.load(stream);
+    return resultVariant.value<QJSValue>();
+}
+
 void tst_QJSValue::toString()
 {
     QJSEngine eng;
@@ -406,6 +414,28 @@ void tst_QJSValue::toString()
     variant = eng.toScriptValue(QUrl());
     QVERIFY(variant.isVariant());
     QVERIFY(variant.toString().isEmpty());
+
+    {
+        QJSValue o = eng.newObject();
+        o.setProperty(QStringLiteral("test"), 42);
+        QCOMPARE(o.toString(), QStringLiteral("[object Object]"));
+
+        o = createUnboundValue(o);
+        QVERIFY(!o.engine());
+        QCOMPARE(o.toString(), QStringLiteral("[object Object]"));
+    }
+
+    {
+        QJSValue o = eng.newArray();
+        o.setProperty(0, 1);
+        o.setProperty(1, 2);
+        o.setProperty(2, 3);
+        QCOMPARE(o.toString(), QStringLiteral("1,2,3"));
+
+        o = createUnboundValue(o);
+        QVERIFY(!o.engine());
+        QCOMPARE(o.toString(), QStringLiteral("1,2,3"));
+    }
 }
 
 void tst_QJSValue::toNumber()
@@ -419,35 +449,43 @@ void tst_QJSValue::toNumber()
     QJSValue null = eng.evaluate("null");
     QCOMPARE(null.toNumber(), 0.0);
     QCOMPARE(qjsvalue_cast<qreal>(null), 0.0);
+    QCOMPARE(createUnboundValue(null).toNumber(), 0.0);
 
     {
         QJSValue falskt = eng.toScriptValue(false);
         QCOMPARE(falskt.toNumber(), 0.0);
+        QCOMPARE(createUnboundValue(falskt).toNumber(), 0.0);
         QCOMPARE(qjsvalue_cast<qreal>(falskt), 0.0);
 
         QJSValue sant = eng.toScriptValue(true);
         QCOMPARE(sant.toNumber(), 1.0);
+        QCOMPARE(createUnboundValue(sant).toNumber(), 1.0);
         QCOMPARE(qjsvalue_cast<qreal>(sant), 1.0);
 
         QJSValue number = eng.toScriptValue(123.0);
         QCOMPARE(number.toNumber(), 123.0);
         QCOMPARE(qjsvalue_cast<qreal>(number), 123.0);
+        QCOMPARE(createUnboundValue(number).toNumber(), 123.0);
 
         QJSValue str = eng.toScriptValue(QString("ciao"));
         QCOMPARE(qIsNaN(str.toNumber()), true);
         QCOMPARE(qIsNaN(qjsvalue_cast<qreal>(str)), true);
+        QCOMPARE(qIsNaN(createUnboundValue(str).toNumber()), true);
 
         QJSValue str2 = eng.toScriptValue(QString("123"));
         QCOMPARE(str2.toNumber(), 123.0);
         QCOMPARE(qjsvalue_cast<qreal>(str2), 123.0);
+        QCOMPARE(createUnboundValue(str2).toNumber(), 123.0);
     }
 
     QJSValue object = eng.newObject();
     QCOMPARE(qIsNaN(object.toNumber()), true);
+    QCOMPARE(qIsNaN(createUnboundValue(object).toNumber()), true);
     QCOMPARE(qIsNaN(qjsvalue_cast<qreal>(object)), true);
 
     QJSValue inv = QJSValue();
     QVERIFY(qIsNaN(inv.toNumber()));
+    QCOMPARE(qIsNaN(createUnboundValue(inv).toNumber()), true);
     QVERIFY(qIsNaN(qjsvalue_cast<qreal>(inv)));
 
     // V2 constructors