Enable 'schema' keyword to be provided without root operations

At a glance

• Identifier: #1166
• Stage: RFC0: Strawman
• Champion: @benjie
• PR: Enable 'schema' keyword to be provided without root operations

Timeline

• Spec PR created on 2025-05-01 by benjie
• Added to 2025-05-01 WG agenda
• Commit pushed: Enable 'schema' keyword to be provided without root operations on 2025-04-30 by @benjie

---

This PR is motivated by:

• #1163

In the above PR we want to be able to indicate the error propagation behavior of a schema. However, I find it displeasing that to do so we would need to also explicitly detail the operations supported by the schema when they would normally be auto-detected based on their names:

+schema @behavior(onError: NO_PROPAGATE) {
+  query: Query
+  mutation: Mutation
+  subscription: Subscription
+}
+
 type Query {
   q: Int
 }

 type Mutation {
   m: Int
 }

 type Subscription {
   s: Int
 }

This PR makes it so that you can use a schema keyword to add directives and/or description to the schema without needing to also specify the root operation types if they can be inferred by the default naming. The above diff would thus become:

+schema @behavior(onError: NO_PROPAGATE)
+
 type Query {
   q: Int
 }

 type Mutation {
   m: Int
 }

 type Subscription {
   s: Int
 }

Much nicer! ✨

This is also useful without the onError feature, since it allows you to apply a description to a schema without having to detail the operations:

+"""Just an example"""
+schema
+
 type Query {
   q: Int
 }

 type Mutation {
   m: Int
 }

 type Subscription {
   s: Int
 }

PR #1164 applies these changes onto #1163; but this PR is mergeable into the spec as-is.