Fixed QJsonObject::find()

The function returns mutable iterator on the object that can later be passed to
e.g. erase(), hence it should detach() to be consistent with
QJsonObject::begin() which also detaches.

Change-Id: Id79e8e012fd5469e06b68fbc9eecb7c6848ce9c1
Reviewed-by: Lars Knoll <lars.knoll@nokia.com>
Reviewed-by: Denis Dzyubenko <denis.dzyubenko@nokia.com>

src/corelib/json/qjsonobject.cpp

@@ -452,6 +452,7 @@ QJsonObject::iterator QJsonObject::find(const QString &key)
     int index = o ? o->indexOf(key, &keyExists) : 0;
     if (!keyExists)
         return end();
+    detach();
     return iterator(this, index);
 }
 

tests/auto/corelib/json/tst_qtjson.cpp

@@ -589,6 +589,16 @@ void TestQtJson::testObjectIteration()
         }
     }
 
+    {
+        QJsonObject object2 = object;
+        QVERIFY(object == object2);
+
+        QJsonObject::iterator it = object2.find(QString::number(5));
+        object2.erase(it);
+        QCOMPARE(object.size(), 10);
+        QCOMPARE(object2.size(), 9);
+    }
+
     {
         QJsonObject::Iterator it = object.begin();
         it += 5;