Be strict about error paths format

At a glance

• Identifier: #1073
• Stage: RFC 3 / Accepted
• Champion: @martinbonnin
• Latest activity: Spec PR merged on 2024-04-04
• Spec PR: https://github.com/graphql/graphql-spec/pull/1073
• Related:
  • #1065
  • wg#1410

Spec PR description

Replace should with must in the description of error paths: This field must be a list of path segments starting...

    {
      "message": "Name for character with ID 1002 could not be fetched.",
      "locations": [{ "line": 6, "column": 7 }],
      "path": ["hero", "heroFriends", 1, "name"]
    }

Anything else will make it impossible to handle errors in error-aware clients. This is especially important for strict-nullability or semantic-non-nullability