ReadRelationships: what is the difference between relationship_filter.optional_relation and nested subject_filter.optional_relation?

[theronic]

Refer ReadRelationships filters.

[vroldanbet]

Hi @theronic, If I understand your question correctly, ReadRelationshipRequest.optional_relation is not a thing, it's optional_limit

[theronic]

@vroldanbet see ReadRelationshipRequest.relationship_filter: https://buf.build/authzed/api/docs/main:authzed.api.v1#authzed.api.v1.RelationshipFilter

Then look inside optional_subject_filter.

[vroldanbet]

@theronic in SpiceDB the subject optional relation allows you to reference, instead of a subject entity, a relation in a subject entity. If you think of a graph, what this allows you to is to reference an edge instead of a node. Example:

definition user {}
 
definition team {
  relation member: user
}
 
definition resource {
  relation reader: user | team#member
  permission view = reader
}
```

In this example, the resource `reader` relation can be assigned to a user or to the members of a team. The `member` part of `team#member` is denoted with `optional_subject_filter.optional_relation` 

[theronic]

@vroldanbet isn't filtering on the member relation covered by relationship_filter.optional_relation = "member"?

[vroldanbet]

@theronic no, that's the relation on the resource, not on the subject.

resource:myres#reader@team:engineering#members  

• reader is the resource relation
• members is the subject relation

[theronic]

Thanks. In the example above, would #members be #member with the schema definition?

[vroldanbet]

@theronic sorry, I meant to write member. Yes, it's team#memter from the schema

[theronic]

Updated title to clarify where these filters are.