Prevent @defer & @stream on root mutation or subscription fields

[robrichard]

Context

@benjie: graphql/graphql-spec#742 (comment)

I personally don't think that @defer or @stream should be available within the root selection set of a Mutation or Subscription operation at this time; we should be restrictive to start with and we can lift restrictions later if there's the impetus to do so.

Decision

Discussed in Dec 2021 WG meeting and there was wide agreement on adding validation preventing @defer and @stream on root selection set of Mutation or Subscription operations.

Status

• defined in spec
• implemented in graphql-js

Related

• Mutation interaction with defer & stream

[robrichard]

Discussed in Dec 2021 WG meeting and there was wide agreement on adding validation preventing @defer and @stream on root selection set of Mutation or Subscription operations.

[michaelstaib]

So shall we put this in a validation rule?

[robrichard]

Yes, I will work on adding it to the spec pr and graphql-js.

[robrichard]

I updated the spec and graphql-js PRs adding a validation rule which prevents defer/stream on root mutation/subscription fields

[michaelstaib]

Awesome... I will adopt the spec changes over the weekend.