Enable conversion from QJSValues containing arrays to container types

We started to convert containers to QJSValues, so that we could use them
as JavaScript arrays. Unfortunately, this would then lead to a type missmatch
when those same values where to be stored in a property of the container
type. This commit fixes this by converting them back to the original
type.

Fixes: QTBUG-80916
Change-Id: I30a3b03e17c34b171d4a6881dfd7801c13e94d80
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>

1 files changed, 24 insertions, 1 deletions

diff --git a/src/qml/jsruntime/qv4engine.cpp b/src/qml/jsruntime/qv4engine.cpp
index c81661033a..81f55673cd 100644
--- a/src/qml/jsruntime/qv4engine.cpp
+++ b/src/qml/jsruntime/qv4engine.cpp
@@ -1508,12 +1508,35 @@ static QVariant toVariant(QV4::ExecutionEngine *e, const QV4::Value &value, int
             return QVariant::fromValue(QV4::JsonObject::toJsonArray(a));
         }
 
+        QVariant retn;
 #if QT_CONFIG(qml_sequence_object)
         bool succeeded = false;
-        QVariant retn = QV4::SequencePrototype::toVariant(value, typeHint, &succeeded);
+        retn = QV4::SequencePrototype::toVariant(value, typeHint, &succeeded);
         if (succeeded)
             return retn;
 #endif
+        retn = QVariant(typeHint, QMetaType::create(typeHint));
+        auto retnAsIterable = retn.value<QtMetaTypePrivate::QSequentialIterableImpl>();
+        if (retnAsIterable._iteratorCapabilities & QtMetaTypePrivate::ContainerIsAppendable) {
+            auto const length = a->getLength();
+            QV4::ScopedValue arrayValue(scope);
+            for (qint64 i = 0; i < length; ++i) {
+                arrayValue = a->get(i);
+                QVariant asVariant = toVariant(e, arrayValue, retnAsIterable._metaType_id, false, visitedObjects);
+                auto originalType = asVariant.userType();
+                bool couldConvert = asVariant.convert(retnAsIterable._metaType_id);
+                if (!couldConvert) {
+                    qWarning() << QLatin1String("Could not convert array value at position %1 from %2 to %3")
+                                                .arg(QString::number(i),
+                                                     QMetaType::typeName(originalType),
+                                                     QMetaType::typeName(retnAsIterable._metaType_id));
+                    // create default constructed value
+                    asVariant = QVariant(retnAsIterable._metaType_id, nullptr);
+                }
+                retnAsIterable.append(asVariant.constData());
+            }
+            return retn;
+        }
     }
 
     if (value.isUndefined())