Problem with field aliases when querying a subgraph schema created from a remote source

[alexander-aleman]

When trying to upgrade from:

• @apollo/federation: 0.14.1
• apollo-server: 2.25.3

to:

• @apollo/subgraph: 2.0.2
• apollo-server: 3.7.0

I seem to be running into an issue with field aliases. I am only experiencing this issue when creating a subgraph from a remote source. See the following example:

example (github):

https://github.com/alexander-aleman/subgraph-example In this example http://localhost:4000 will serve as the remote source for the subgraph on http://localhost:4001

tested with:

• NodeJS: v16.13.2
• NPM version: 8.3.1

environments:

http://localhost:4000/ http://localhost:4001/

Requests working on both environments:

request:

{
  test {
    nested {
      structure
    }
  }
}

response

{
    "data": {
        "test": {
            "nested": {
                "structure": "here"
            }
        }
    }
}

request:

{
  a: test {
    nested {
      structure
    }
  }
}

response

{
    "data": {
        "a": {
            "nested": {
                "structure": "here"
            }
        }
    }
}

Failing request:

request:

{
  a: test {
    b: nested {
      c: structure
    }
  }
}

response from http://localhost:4000/ :

{
    "data": {
        "a": {
            "b": {
                "c": "here"
            }
        }
    }
}

response from http://localhost:4001/ :

{
    "errors": [
        {
            "message": "Cannot return null for non-nullable field NestedStructure.nested.",
            "locations": [
                {
                    "line": 3,
                    "column": 6
                }
            ],
            "path": [
                "a",
                "b"
            ],
            "extensions": {
                "code": "INTERNAL_SERVER_ERROR",
                "exception": {
                    "stacktrace": [
                        "Error: Cannot return null for non-nullable field NestedStructure.nested.",
                        "    at completeValue (/home/alexander/sites/apollo-subgraph-error/node_modules/graphql/execution/execute.js:592:13)",
                        "    at executeField (/home/alexander/sites/apollo-subgraph-error/node_modules/graphql/execution/execute.js:487:19)",
                        "    at executeFields (/home/alexander/sites/apollo-subgraph-error/node_modules/graphql/execution/execute.js:411:20)",
                        "    at completeObjectValue (/home/alexander/sites/apollo-subgraph-error/node_modules/graphql/execution/execute.js:906:10)",
                        "    at completeValue (/home/alexander/sites/apollo-subgraph-error/node_modules/graphql/execution/execute.js:633:12)",
                        "    at completeValue (/home/alexander/sites/apollo-subgraph-error/node_modules/graphql/execution/execute.js:582:23)",
                        "    at /home/alexander/sites/apollo-subgraph-error/node_modules/graphql/execution/execute.js:484:9",
                        "    at processTicksAndRejections (node:internal/process/task_queues:96:5)",
                        "    at async Promise.all (index 0)",
                        "    at async execute (/home/alexander/sites/apollo-subgraph-error/node_modules/apollo-server-core/dist/requestPipeline.js:205:20)"
                    ]
                }
            }
        }
    ],
    "data": null
}

[alexander-aleman]

Possibly related to https://github.com/ardatan/graphql-tools/issues/3267

[process0]

Experiencing the same issue