facebook/relay · error

Expected to get selection type.

Error message

Expected to get selection type.

What it means

Guard in get_field_parent_type_name: walking a resolution path from a linked/scalar field selection to its parent selection must resolve to a concrete schema type. Firing means the parent type lookup (find_parent_type) returned None, typically because the selection references a type absent from the schema set or the resolution path was built against a different schema.

Source

Thrown at compiler/crates/resolution-path/src/selection_parent_type.rs:170

            ResolutionPath::Ident(IdentPath {
                inner: _,
                parent:
                    IdentParent::LinkedFieldName(LinkedFieldPath {
                        inner: _,
                        parent: selection,
                    }),
            }) => selection.parent.find_parent_type(&schema),
            ResolutionPath::Ident(IdentPath {
                inner: _,
                parent:
                    IdentParent::ScalarFieldName(ScalarFieldPath {
                        inner: _,
                        parent: selection,
                    }),
            }) => selection.parent.find_parent_type(&schema),
            _ => None,
        }
        .expect("Expected to get selection type.");

        schema.get_type_name(selection_type)
    }

    #[test]
    fn test_me() {
        let source = r#"
        query Foo {
            me {
                id
                ... {
                    name
                }
                emailAddresses
                screennames {
                    service
                }
                author {

View on GitHub (pinned to 668b1b85e0)

Solutions

1. Verify the referenced parent type exists in the schema set used to build the resolution path
2. Check that resolution paths are not reused across different schemas
3. Return a diagnostic error instead of unwrap when the parent type is missing

When it happens

Trigger: Thrown at compiler/crates/resolution-path/src/selection_parent_type.rs:170 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of facebook/relay@668b1b85e0 (2026-09-02). Data as JSON: /api/errors/2ab3e43d236e0393. Report an issue: GitHub.