hasura/graphql-engine · error

no fields are selected

Error message

no fields are selected

What it means

Error returned by normalize_selection_sets (selection_set.rs:141) when a selection set for a field or operation contains no actual field selections — for example a set consisting only of fragments that resolve to nothing, or `field { }` with an empty braces block. GraphQL requires at least one field in every selection set.

Source

Thrown at v3/crates/graphql/lang-graphql/src/validation/error.rs:186

        argument_name: ast::Name,
    },
    #[error(
        "argument {argument_name} on field {field_name} of type {type_name} is defined more than once"
    )]
    DuplicateArguments {
        type_name: ast::TypeName,
        field_name: ast::Name,
        argument_name: ast::Name,
    },
    #[error(
        "required argument {argument_name} not found on field {field_name} of type {type_name}"
    )]
    RequiredArgumentNotFound {
        type_name: ast::TypeName,
        field_name: ast::Name,
        argument_name: ast::Name,
    },
    #[error("no fields are selected")]
    FieldSelectionSetIsEmpty,
}

View on GitHub (pinned to 724551b9ae)

Solutions

1. Add at least one concrete subfield inside the empty `{ }` block
2. If building queries programmatically, skip emitting the field entirely when the subfield list is empty
3. Ensure fragments referenced in the set actually apply to the parent type

Example fix

# before
query { user { posts { } } }
# after
query { user { posts { id } } }

// When building selections programmatically, require at least one subfield
fn build_field(name: &str, subs: &[Field]) -> String {
    assert!(!subs.is_empty(), "selection set must not be empty");
    format!("{name} {{ {} }}", subs.iter().map(to_string).collect::<Vec<_>>().join(" "))
}

// Catch Error::FieldSelectionSetIsEmpty during normalize_selection_sets and reject the generated query before execution

When it happens

Trigger: A query or nested field with an empty selection set `{ }`, or a selection set whose fragments/__typename-only content normalizes to zero fields, hits `Err(Error::FieldSelectionSetIsEmpty)` during normalize_selection_sets.

Common situations: Programmatic query construction that emits empty braces when a list of subfields is empty, templates with optional subselections, or fragments that don't match the type and get filtered out.

Related errors

• a selection set is specified on field '{field_name}' of non-
• validation failed: {0}
• Unexpected value: expecting {expected_kind:}, but found: {fo
• '{name:}' is not a valid GraphQL name.
• '{alias:} is not a valid alias

AI-assisted analysis of hasura/graphql-engine@724551b9ae (2026-08-28). Data as JSON: /api/errors/cc6b49874b72ad95. Report an issue: GitHub.