Fix generic conversion of list-like values to JSON arrays

Previously, QVariant::toList() was used to convert a QVariant to a
QVariantList. This only works for actual QVariantLists and QStringList,
however. This patch uses QVariant::value<QVariantList>() which works in all
cases.
A better approach would be to extract a QSequentialIterable, but QTBUG-42016
currently prevents this.

Change-Id: I732cc88a6db2ec5d990760364a9db98a52521f6b
Reviewed-by: Milian Wolff <milian.wolff@kdab.com>

2 files changed, 11 insertions, 1 deletions

diff --git a/src/webchannel/qmetaobjectpublisher.cpp b/src/webchannel/qmetaobjectpublisher.cpp
index 3b2c016..917bbf7 100644
--- a/src/webchannel/qmetaobjectpublisher.cpp
+++ b/src/webchannel/qmetaobjectpublisher.cpp
@@ -621,7 +621,10 @@ QJsonValue QMetaObjectPublisher::wrapResult(const QVariant &result, QWebChannelA
 #endif
     } else if (result.canConvert<QVariantList>()) {
         // recurse and potentially wrap contents of the array
-        return wrapList(result.toList(), transport);
+        // *don't* use result.toList() as that *only* works for QVariantList and QStringList!
+        // Also, don't use QSequentialIterable (yet), since that seems to trigger QTBUG-42016
+        // in certain cases.
+        return wrapList(result.value<QVariantList>(), transport);
     }
 
     return QJsonValue::fromVariant(result);
diff --git a/tests/auto/webchannel/tst_webchannel.cpp b/tests/auto/webchannel/tst_webchannel.cpp
index 57aab53..27ef81c 100644
--- a/tests/auto/webchannel/tst_webchannel.cpp
+++ b/tests/auto/webchannel/tst_webchannel.cpp
@@ -797,6 +797,13 @@ void TestWebChannel::testWrapValues()
         QVERIFY(value.isDouble());
         QCOMPARE(value.toInt(), (int) flags);
     }
+    {
+        QVector<int> vec{1, 2, 3};
+        QVariant variant = QVariant::fromValue(vec);
+        QJsonValue value = channel.d_func()->publisher->wrapResult(variant, m_dummyTransport);
+        QVERIFY(value.isArray());
+        QCOMPARE(value.toArray(), QJsonArray({1, 2, 3}));
+    }
 }
 
 void TestWebChannel::testWrapObjectWithMultipleTransports()