GraphQL Subscriptions should handle errors in the source stream

At a glance

• Identifier: #1126
• Stage: RFCX: Closed 2024-11-21T15:14:32Z
• Champion: @benjie
• PR: GraphQL Subscriptions should handle errors in the source stream

Timeline

• Spec PR created on 2024-11-21 by benjie
• Commit pushed: Handle errors raised by sourceStream on 2024-11-21 by @benjie

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Currently if sourceStream generates an error, then responseStream repeats the error. This is the behavior implemented in graphql-js and is problematic.

GraphQL captures execution errors and wraps them in an { errors: [...] } payload for query and mutation operations; it should do the same for stream errors in a subscription operation.

This PR makes this behavior explicit.