QVariant to QJsonValue::Null conversion

Adds a few missing parts of the conversion from QVariant to QJsonValue
after the introduction of the nullptr QVariant. The conversion the other
way is already implemented.

Change-Id: I8b25dec4b476c4761c5098a60944ff11c36f8bec
Reviewed-by: Olivier Goffart (Woboq GmbH) <ogoffart@woboq.com>

3 files changed, 13 insertions, 3 deletions

diff --git a/src/corelib/json/qjsonvalue.cpp b/src/corelib/json/qjsonvalue.cpp
index 5a906dda7b..4b52014db1 100644
--- a/src/corelib/json/qjsonvalue.cpp
+++ b/src/corelib/json/qjsonvalue.cpp
@@ -349,6 +349,12 @@ QJsonValue &QJsonValue::operator =(const QJsonValue &other)
     \row
         \li
             \list
+                \li QMetaType::Nullptr
+            \endlist
+        \li QJsonValue::Null
+    \row
+        \li
+            \list
                 \li QMetaType::Bool
             \endlist
         \li QJsonValue::Bool
@@ -393,6 +399,8 @@ QJsonValue &QJsonValue::operator =(const QJsonValue &other)
 QJsonValue QJsonValue::fromVariant(const QVariant &variant)
 {
     switch (variant.userType()) {
+    case QMetaType::Nullptr:
+        return QJsonValue(Null);
     case QVariant::Bool:
         return QJsonValue(variant.toBool());
     case QVariant::Int:
diff --git a/src/corelib/kernel/qvariant.cpp b/src/corelib/kernel/qvariant.cpp
index 72ae3b063f..ccfa7d0d38 100644
--- a/src/corelib/kernel/qvariant.cpp
+++ b/src/corelib/kernel/qvariant.cpp
@@ -3085,6 +3085,7 @@ bool QVariant::canConvert(int targetTypeId) const
 
     if (currentType == QMetaType::QJsonValue) {
         switch (targetTypeId) {
+        case QMetaType::Nullptr:
         case QMetaType::QString:
         case QMetaType::Bool:
         case QMetaType::Int:
diff --git a/tests/auto/corelib/json/tst_qtjson.cpp b/tests/auto/corelib/json/tst_qtjson.cpp
index 1194260efa..17892b44a2 100644
--- a/tests/auto/corelib/json/tst_qtjson.cpp
+++ b/tests/auto/corelib/json/tst_qtjson.cpp
@@ -1103,6 +1103,7 @@ void tst_QtJson::fromVariant()
     jsonObject["string"] = stringValue;
     jsonObject["array"] = jsonArray_variant;
 
+    QCOMPARE(QJsonValue::fromVariant(QVariant::fromValue(nullptr)), QJsonValue(QJsonValue::Null));
     QCOMPARE(QJsonValue::fromVariant(QVariant(boolValue)), QJsonValue(boolValue));
     QCOMPARE(QJsonValue::fromVariant(QVariant(intValue)), QJsonValue(intValue));
     QCOMPARE(QJsonValue::fromVariant(QVariant(uintValue)), QJsonValue(static_cast<double>(uintValue)));
@@ -1179,7 +1180,7 @@ void tst_QtJson::toVariantMap()
     array.append(true);
     array.append(999.);
     array.append(QLatin1String("string"));
-    array.append(QJsonValue());
+    array.append(QJsonValue::Null);
     object.insert("Array", array);
 
     map = object.toVariantMap();
@@ -1203,12 +1204,12 @@ void tst_QtJson::toVariantHash()
     QVERIFY(hash.isEmpty());
 
     object.insert("Key", QString("Value"));
-    object.insert("null", QJsonValue());
+    object.insert("null", QJsonValue::Null);
     QJsonArray array;
     array.append(true);
     array.append(999.);
     array.append(QLatin1String("string"));
-    array.append(QJsonValue());
+    array.append(QJsonValue::Null);
     object.insert("Array", array);
 
     hash = object.toVariantHash();