reading a custom datatype array returns ExtensionObject

Description

When you trie to read an array with type of custom datatypes, you get an ExtensionObject instead of the custom data type. You can extract the array from the ExtensionObject, but its not as expected. When reading a scalar value everything works fine.

It looks like it is a problem in the client code, because I found the problem when writing client code for a server that is using the Softing Toolkit.

Background Information / Reproduction Steps

Take examples/custom_datatype/client_types_custom.c and after UA_Client_readValueAttribute add:

    if(retval == UA_STATUSCODE_GOOD) {
        if (UA_Variant_hasArrayType(&value, &PointType)) {
            Point *p = (Point *)value.data;
            printf("Point = %f, %f, %f \n", p->x, p->y, p->z);
        }
        else
            printf("Error type: %s\n", value.type->typeName);
    }

in examples/custom_datatype/server_types_custom.c replace add3PointDataType and add3DPointVariable:

static void
add3PointDataType(UA_Server *server) {
    UA_VariableTypeAttributes dattr = UA_VariableTypeAttributes_default;
    dattr.description = UA_LOCALIZEDTEXT("en-US", "3D Point");
    dattr.displayName = UA_LOCALIZEDTEXT("en-US", "3D Point");
    dattr.dataType = PointType.typeId;
    dattr.valueRank = UA_VALUERANK_ONE_DIMENSION;
    UA_UInt32 arrayDims[1] = { 2 };
    dattr.arrayDimensions = arrayDims;
    dattr.arrayDimensionsSize = 1;
    Point p[2] = { { 3.0, 4.0, 5.0 },{ 1.0, 2.0, 5.0 } };
    UA_Variant_setArray(&dattr.value, p, 2, &PointType);

    UA_Server_addVariableTypeNode(server, PointType.typeId,
                                  UA_NODEID_NUMERIC(0, UA_NS0ID_BASEDATAVARIABLETYPE),
                                  UA_NODEID_NUMERIC(0, UA_NS0ID_HASSUBTYPE),
                                  UA_QUALIFIEDNAME(1, "3D.Point"),
                                  UA_NODEID_NUMERIC(0, UA_NS0ID_BASEDATAVARIABLETYPE),
                                  dattr, NULL, NULL);

}

static void
add3DPointVariable(UA_Server *server) {

    UA_VariableAttributes vattr = UA_VariableAttributes_default;
    vattr.description = UA_LOCALIZEDTEXT("en-US", "3D Point");
    vattr.displayName = UA_LOCALIZEDTEXT("en-US", "3D Point");
    vattr.dataType = PointType.typeId;

    vattr.valueRank = UA_VALUERANK_ONE_DIMENSION;
    UA_UInt32 arrayDims[1] = { 2 };
    vattr.arrayDimensions = arrayDims;
    vattr.arrayDimensionsSize = 1;
    Point p[2] = { { 3.0, 4.0, 5.0 },{ 1.0, 2.0, 5.0 } };
    UA_Variant_setArray(&vattr.value, p, 2, &PointType);

    UA_Server_addVariableNode(server, UA_NODEID_STRING(1, "3D.Point"),
        UA_NODEID_NUMERIC(0, UA_NS0ID_OBJECTSFOLDER),
        UA_NODEID_NUMERIC(0, UA_NS0ID_ORGANIZES),
        UA_QUALIFIEDNAME(1, "3D.Point"),
        PointType.typeId, vattr, NULL, NULL);
}

Checklist

Please provide the following information:

[x] open62541 Version (release number or git tag): master
[ ] Other OPC UA SDKs used (client or server):
[x] Operating system: Windows
[ ] Logs (with UA_LOGLEVEL set as low as necessary) attached
[ ] Wireshark network dump attached
[ ] Self-contained code example attached
[ ] Critical issue

open62541 / open62541