🐛: Mutations with @defer only responds with the first part

To clarify, this is happening from a non-federated AS4 instance, not router.

Intended outcome: Using the useMutation hook with a mutation with @defer results in only the first chunk loading.

For example, given a server responding with:

---
content-type: application/json; charset=utf-8

{"hasNext":true,"data":{"makePayment":{"id":"1afa84cc-26a5-4820-a496-33c8366e03cd","__typename":"MakePaymentResult"}}}
---
content-type: application/json; charset=utf-8

{"hasNext":false,"incremental":[{"path":["makePayment"],"data":{"paymentStatus":{"__typename":"PaymentSuccess","id":"2a3a1ddd-81e1-4535-8a9c-e8dc1ce38026","billedAmount":39.854330085558395},"__typename":"MakePaymentResult"}}]}
-----

Only

{"makePayment":{"id":"1afa84cc-26a5-4820-a496-33c8366e03cd","__typename":"MakePaymentResult"}

is reported in the data object.

Actual outcome: Mutations update with the correct data, same as with useQuery which works as expected.

How to reproduce the issue: Example Repo: https://github.com/lleadbet/graphql-galaxy-demo

Versions

  System:
    OS: macOS 12.6
  Binaries:
    Node: 16.16.0 - ~/.volta/tools/image/node/16.16.0/bin/node
    Yarn: 1.22.19 - ~/.volta/tools/image/yarn/1.22.19/bin/yarn
    npm: 8.11.0 - ~/.volta/tools/image/node/16.16.0/bin/npm
  Browsers:
    Chrome: 107.0.5304.110
    Firefox: 106.0.5
    Safari: 16.0
  npmPackages:
    @apollo/client: ^3.7.1 => 3.7.1 

[lleadbet]

To clarify, this is happening from a non-federated AS4 instance, not router

[alessbell]

Opened the router issue here: https://github.com/apollographql/router/issues/2099