Printing the @oneOf directive

[hayes]

It looks like currently the printSchema function doesn't have any handling for @oneOf.

I'm not sure if this is intentional or not, because I know printing directives has historically been a controversial topic, but my expectation would be that for directives that are part of the spec and have a corresponding option in the options when creating the type/field in code (eg deprecationReason/@deprecated ) would be printed when using printSchema.

I'm happy to make a PR to add this, and it looks like it should be a pretty simple fix handled here: https://github.com/graphql/graphql-js/blob/main/src/utilities/printSchema.ts#L207C5-L207C5

[benjie]

Thanks for spotting this! Can confirm that the RFC definitely states the directive should be present; this isn't "metadata" (unlike graphql/graphql-spec#300) - it's a concrete __Type.isOneOf introspection field and without this we'd lose introspection<->SDL equivalence.