Added missing detach() to QJsonObject::take()

We also need to detach() the taken value in case the compaction triggers and
modifies the underlaying data.

Change-Id: Idcdeba4236b8e208d107d41be2decbdfc5721300
Reviewed-by: Bjørn Erik Nilsen <post@bjoernen.com>
Reviewed-by: Denis Dzyubenko <denis@ddenis.info>

2 files changed, 19 insertions, 3 deletions

diff --git a/src/corelib/json/qjsonobject.cpp b/src/corelib/json/qjsonobject.cpp
index e595753fec..1bdd872e78 100644
--- a/src/corelib/json/qjsonobject.cpp
+++ b/src/corelib/json/qjsonobject.cpp
@@ -390,13 +390,14 @@ QJsonValue QJsonObject::take(const QString &key)
     if (!keyExists)
         return QJsonValue(QJsonValue::Undefined);
 
-    QJsonPrivate::Entry *e = o->entryAt(index);
+    QJsonValue v(d, o, o->entryAt(index)->value);
+    detach();
     o->removeItems(index, 1);
     ++d->compactionCounter;
     if (d->compactionCounter > 32u && d->compactionCounter >= unsigned(o->length) / 2u)
         compact();
 
-    return QJsonValue(d, o, e->value);
+    return v;
 }
 
 /*!
diff --git a/tests/auto/corelib/json/tst_qtjson.cpp b/tests/auto/corelib/json/tst_qtjson.cpp
index 82656d6309..4a8ef293ff 100644
--- a/tests/auto/corelib/json/tst_qtjson.cpp
+++ b/tests/auto/corelib/json/tst_qtjson.cpp
@@ -303,12 +303,27 @@ void tst_QtJson::testObjectSimple()
     QVERIFY2(!object.contains("boolean"), "key boolean should have been removed");
 
     QJsonValue taken = object.take("value");
-//    QCOMPARE(taken, value);
+    QCOMPARE(taken, value);
     QVERIFY2(!object.contains("value"), "key value should have been removed");
 
     QString before = object.value("string").toString();
     object.insert("string", QString::fromLatin1("foo"));
     QVERIFY2(object.value("string").toString() != before, "value should have been updated");
+
+    size = object.size();
+    QJsonObject subobject;
+    subobject.insert("number", 42);
+    subobject.insert(QLatin1String("string"), QLatin1String("foobar"));
+    object.insert("subobject", subobject);
+    QCOMPARE(object.size(), size+1);
+    QJsonValue subvalue = object.take(QLatin1String("subobject"));
+    QCOMPARE(object.size(), size);
+    QCOMPARE(subvalue.toObject(), subobject);
+    // make object detach by modifying it many times
+    for (int i = 0; i < 64; ++i)
+        object.insert(QLatin1String("string"), QLatin1String("bar"));
+    QCOMPARE(object.size(), size);
+    QCOMPARE(subvalue.toObject(), subobject);
 }
 
 void tst_QtJson::testObjectSmallKeys()