Routing error when directly fetching properties on interfaces

[alexus37]

Component(s)

router

router version

v0.0.0-20240927172855-3e390cd5cf6c

What happened?

Description

The router is encountering an error when I try to retrieve the query plan for queries that directly fetch data from interfaces.

Steps to Reproduce

Execute a query like this:

{
  repository(name: "<REDACTED>", owner: "<REDACTED>") {
    issue(number: 1) {
      timelineItems(since: "<REDACTED>", first: 1) {
        edges {
          node {
            ... on Comment {
              id
              bodyText
            }
          }
        }
      }
    }
  }
}

where the Comment is an interface and not a type.

interface Comment {
  
  """
  The body rendered to text.
  """
  bodyText: String!

  """
  The Node ID of the Comment object
  """
  id: ID!
}

Expected Result

The correct query plan is being returned! This works perfectly when I directly fetch data from a type that implements that interface or when I simply retrieve the ID.

Actual Result

We are getting a execution plan failure.

Environment information

I am using the following headers:

{
  "X-WG-TRACE": "false",
  "X-WG-Skip-Loader": "true",
  "X-WG-Include-Query-Plan": "true",
}

Log output

AM ERROR internal error {"error": "1 error occurred:\n\t* could not resolve a field: internal: nodesResolvableVisitor: could not select the datasource to resolve Repository.__typename on path query.repository.__typename\n\n"}

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[apatelWU]

I am facing similar issue as well where __typename required on interface object when fetching Id. If we are fetch other attributes of interface, then its working as expected.

For instance: SubGraph A

interface A {
  a1Field: ID!
  a2Field: String
  a3Field: String
}

type XA implements A {
  a1Field: ID!
  a2Field: String
  a3Field: String
  xa1Field: String
}

type XB implements A {
  a1Field: ID!
  a2Field: String
  a3Field: String
  xb1Field: String
}

SubGraph B

type B {
  b1Field: ID!
  b2Field: String
  a: A!
}

query details:

query Test {
  b(id: ID!) {
    b1Field
    b2Field
    a {
      a1Field
    }
  }
}

The above query returns following error: Subgraph 'B' returned invalid value 'A' for __typename field.

QueryPlan {
    SingleFetch(service: "B") {
        {
            b(id: $Id) {
                b1Field
                b2Field
                a {
                    __typename
                    a1Field
                }
            }
        }
    }
}

However, following queries returns data as expected

query Test {
  b(id: ID!) {
    b1Field: ID!
    b2Field: String
    a {
      a1Field
      a2Field
    }
  }
}

or

query Test {
  b(id: ID!) {
    b1Field: ID!
    b2Field: String
    a {
      __typename
      a1Field
    }
  }
}

[YassineElbouchaibi]

Noticed the same thing while creating repro for #1440.

[rlch]

+1, preventing us from adopting Cosmo.

[devsergiy]

Hi @alexus37 @apatelWU

please try out this version https://github.com/wundergraph/cosmo/releases/tag/router%400.175.1

Runtime error should no longer happen

@YassineElbouchaibi @rlch please try too, in case issue won't be resolved please create separate issues with the subgraph sdls and failing queries if any

[saerdnaer]

Hi, we still have the same error with router 0.214.0 + 0.215.1:

DGS-A

interface Node {
  id: ID!
}

type Article implements Node {
  id: ID!
  title: String
}

DGS-B

type Article @key(fields : "id") {
  id: ID! @external
  recommendations: RecommendationConnection! @requires(fields : "id")
}

type Query {
  recommendations(itemId: ID!): RecommendationConnection!
}

type RecommendationConnection {
  items: [RecommendationEntry]!
}

type RecommendationEntry {
  item: Article!
  score
}

Query:

query recoDemo {
  recommendations(itemId: "kmp:cms:VWh4TFJUbw") {
    __typename
    items {
      __typename
      item {
        __typename
        id
      }
    }
  }
}

Errors:

DEBUG core/graphql_prehandler.go:970 failed to plan operation 
{"hostname": "cosmo-router-playground-7456797776-54b6c", "pid": 1, "service": "@wundergraph/router", "service_version": "0.214.0", "request_id": "878bab0236eddd4acc84c57ab3589fac", "trace_id": "55a556437e16f2f9e60959545094db27", 
"error": "could not resolve a field: internal: nodesResolvableVisitor: could not select the datasource to resolve Article.id on path query.recommendations.items.item.id"}

DEBUG core/errors.go:308 operation error 
{"hostname": "cosmo-router-playground-7456797776-54b6c", "pid": 1, "service": "@wundergraph/router", "service_version": "0.214.0", "request_id": "878bab0236eddd4acc84c57ab3589fac", "trace_id": "55a556437e16f2f9e60959545094db27", 
"error": "could not resolve a field: internal: nodesResolvableVisitor: could not select the datasource to resolve Article.id on path query.recommendations.items.item.id"}

ERROR core/errors.go:102 internal error 
{"hostname": "cosmo-router-playground-7456797776-54b6c", "pid": 1, "service": "@wundergraph/router", "service_version": "0.214.0", "request_id": "878bab0236eddd4acc84c57ab3589fac", "trace_id": "55a556437e16f2f9e60959545094db27", 
"error": "1 error occurred:\n\t* could not resolve a field: internal: nodesResolvableVisitor: could not select the datasource to resolve Article.id on path query.recommendations.items.item.id\n\n"}

[devsergiy]

Hi @saerdnaer

Could you provide complete schemas for your subgraphs? Or give us your execution config.json (please share here or in the discord)

Thanks, Wundergraph Team

[saerdnaer]

@devsergiy I sent you the complete subgraphs, how can i access the config.json?

[devsergiy]

@saerdnaer config.json are result of running wgc router compose

[devsergiy]

No activity for a long time, considering the issue was fixed

If you have any other problem, please create a separate issue

Thanks, Wundergraph Team