QJsonValue: fix incorrect to{Array,Object} when the value is empty

This is a repeat of commit de6ced66920600e659dbaa2509526a3bcb0b3360
"QCborValue: fix incorrect to{Array,Map} when the value is empty" (6.4),
which fixed the same thing for QCborValue. I've just copied the exact
same implementation onto the QJsonValue functions.

Fixes: QTBUG-104085
Change-Id: I175efddd75f24ae59057fffd16f6b257bf7ed36d
Reviewed-by: Sona Kurazyan <sona.kurazyan@qt.io>
(cherry picked from commit e114fec62adf13b8c21ca890fb748cb27f391c25)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

1 files changed, 16 insertions, 2 deletions

diff --git a/tests/auto/corelib/serialization/json/tst_qtjson.cpp b/tests/auto/corelib/serialization/json/tst_qtjson.cpp
index fe97e03690..7e01ca3f98 100644
--- a/tests/auto/corelib/serialization/json/tst_qtjson.cpp
+++ b/tests/auto/corelib/serialization/json/tst_qtjson.cpp
@@ -768,15 +768,20 @@ void tst_QtJson::testValueObject()
 void tst_QtJson::testValueArray()
 {
     QJsonArray array;
+    QJsonArray otherArray = {"wrong value"};
+    QJsonValue value(array);
+    QCOMPARE(value.toArray(), array);
+    QCOMPARE(value.toArray(otherArray), array);
+
     array.append(999.);
     array.append(QLatin1String("test"));
     array.append(true);
-
-    QJsonValue value(array);
+    value = array;
 
     // if we don't modify the original JsonArray, toArray()
     // on the JsonValue should return the same object (non-detached).
     QCOMPARE(value.toArray(), array);
+    QCOMPARE(value.toArray(otherArray), array);
 
     // if we modify the original array, it should detach
     array.append(QLatin1String("test"));
@@ -786,14 +791,23 @@ void tst_QtJson::testValueArray()
 void tst_QtJson::testObjectNested()
 {
     QJsonObject inner, outer;
+    QJsonObject otherObject = {{"wrong key", "wrong value"}};
+    QJsonValue v = inner;
+    QCOMPARE(v.toObject(), inner);
+    QCOMPARE(v.toObject(otherObject), inner);
+
     inner.insert("number", 999.);
     outer.insert("nested", inner);
 
     // if we don't modify the original JsonObject, value()
     // should return the same object (non-detached).
     QJsonObject value = outer.value("nested").toObject();
+    v = value;
     QCOMPARE(value, inner);
     QCOMPARE(value.value("number").toDouble(), 999.);
+    QCOMPARE(v.toObject(), inner);
+    QCOMPARE(v.toObject(otherObject), inner);
+    QCOMPARE(v["number"].toDouble(), 999.);
 
     // if we modify the original object, it should detach and not
     // affect the nested object