Fail when null is in a list of values in a query by attribute values

[danielvillalbamota]

Bug description
A clear and concise description of what the bug is. Please do not forget to add:

Having entities where for some of them have a specific attr, e.g. municipality with value null, a query by a list of values of this attributes gets an error.

How to reproduce it
Steps to reproduce the behavior (as an example)

1. Create an entity this way:

   curl -iX POST 'http://localhost:1026/v2/entities' \
   -H 'Content-Type: application/json' \
   -d '
   {
       "id": "Bug:007",
       "type": "bug",
       "status": {
           "type": "Text",
           "value": "fixed"
       },
       "municipality": {
           "value": null,
           "type": "Text"
       }  
   }'

2. When make the following query:

curl --location --request GET 'http://host:1026/v2/entities?q=municipality:null,alcobendas' \
--header 'Fiware-Service: service' \
--header 'Fiware-ServicePath: /subservice' \

3. See error in the request response

400 Bad Request
{
    "error": "BadRequest",
    "description": "invalid JSON value type in list"
}

4. When the query is just the null value the answer is correct

curl --location --request GET 'http://host:1026/v2/entities?q=municipality:null' \
--header 'Fiware-Service: service' \
--header 'Fiware-ServicePath: /subservice' \
--header 'X-Auth-Token: ...

Response:
200 OK

[
    ...,
    {
        "id": "Bug:007",
        "type": "bug",
        "municipality": {
            "type": "Text",
            "value": null,
            "metadata": {}
        },
        "status": {
            "type": "Text",
            "value": "fixed",
            "metadata": {}
        }
    }
]

Expected behavior

To be able to retrieve both set of entities, the ones with the municipality=alcobendas and the others with municipality=null

Additional information

NA

[fgalan]

Looking in StringFilter.h:

typedef enum StringFilterValueType
{
  ...
  SfvtNumberList,
  SfvtDateList,
  SfvtStringList
} StringFilterValueType;

So it seems our internal data structures are not though for mixing different types (string and null in this case) but let me think if I can come with some creative solution for this :)

[fgalan]

We will use a new bool flag named nullInList to mark the existence of null within a list. Not a very smart solution, but it'll work.

[fgalan]

PR #4123

[danielvillalbamota]

It seems when null is in the list of values, the CB retrieve entities without the filtered attribute (municipality), but what is expected are the entities with explicit null in the value as when just one value null is used (not a list).

[fgalan]

It seems when null is in the list of values, the CB retrieve entities without the filtered attribute (municipality), but what is expected are the entities with explicit null in the value as when just one value null is used (not a list).

Fixed by PR #4127

[danielvillalbamota]

It works