Skip to content

Comments

OneOf Inhabitability#4564

Open
jbellenger wants to merge 1 commit intographql:nextfrom
jbellenger:jbellenger-oneof-inhabitability
Open

OneOf Inhabitability#4564
jbellenger wants to merge 1 commit intographql:nextfrom
jbellenger:jbellenger-oneof-inhabitability

Conversation

@jbellenger
Copy link
Contributor

@jbellenger jbellenger commented Feb 17, 2026

This PR implements the validation described at graphql/graphql-spec#1211

More discussion is at the link above, but the core issue is around uninhabited OneOf types -- the property that a type can be defined in a way that a value cannot be generated for it.

The simplest example of an uninhabited type is this recursive OneOf:

input A @oneOf { a:A }

While this type definition is currently valid by the rules of OneOf types and circular input types, it violates the spirit of the Circular References because it does not allow construction of a finite value. This uninhabitation property applies to any closed subgraph of OneOf types.

This PR adds a new validator for OneOf inhabitation. I've tried to follow the existing conventions, though I'm also new here and might have missed something. Any feedback on style or substance is welcome.

@vercel
Copy link

vercel bot commented Feb 17, 2026

@jbellenger is attempting to deploy a commit to the The GraphQL Foundation Team on Vercel.

A member of the Team first needs to authorize it.

@jbellenger jbellenger changed the base branch from 16.x.x to v17-alpha February 17, 2026 12:29
@jbellenger jbellenger changed the base branch from v17-alpha to next February 17, 2026 12:35
@jbellenger jbellenger marked this pull request as ready for review February 17, 2026 13:29
@jbellenger jbellenger requested a review from a team as a code owner February 17, 2026 13:29
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Labels

None yet

Projects

None yet

Development

Successfully merging this pull request may close these issues.

1 participant