hasura/graphql-engine · error · TypecheckIssue

Typecheck failed for field {field_name:} in object type {obj

Error message

Typecheck failed for field {field_name:} in object type {object_type:}: {error:}

What it means

A TypecheckIssue that wraps a nested TypecheckError for one specific field of an object type, adding context: the field name, the object type it belongs to, and the underlying error. It lets you pinpoint which key inside an object literal failed typechecking.

Source

Thrown at v3/crates/metadata-resolve/src/helpers/typecheck.rs:36

    },
    #[error("Error in array item: {inner_error:}")]
    ArrayItemMismatch { inner_error: Box<TypecheckError> },
    #[error("Expected an array but instead got value {value:}")]
    NonArrayValue { value: serde_json::Value },
    #[error("Expected a non-null value but received null")]
    NullInNonNullableColumn,
}

#[derive(Error, Debug, PartialEq)]
/// Issues that can occur when typechecking a value against an object type
pub enum TypecheckIssue {
    #[error("Expected an object value of type {expected:} but got value {actual:}")]
    ObjectTypeMismatch {
        expected: Qualified<CustomTypeName>,
        actual: serde_json::Value,
    },

    #[error("Typecheck failed for field {field_name:} in object type {object_type:}: {error:}")]
    ObjectTypeField {
        field_name: FieldName,
        object_type: Qualified<CustomTypeName>,
        error: TypecheckError,
    },

    #[error(
        "Found a literal value but the argument is a boolean expression type '{boolean_expression_type_name}'"
    )]
    LiteralValueUsedForBooleanExpression {
        boolean_expression_type_name: Qualified<CustomTypeName>,
    },
}

impl ShouldBeAnError for TypecheckIssue {
    fn should_be_an_error(&self, flags: &open_dds::flags::OpenDdFlags) -> bool {
        match self {
            TypecheckIssue::ObjectTypeField { .. } | TypecheckIssue::ObjectTypeMismatch { .. } => {

View on GitHub (pinned to 724551b9ae)

Solutions

1. Inspect the nested {error:} and fix the named {field_name:} in the literal
2. Align the field's value with the field's declared type in the object type definition
3. Re-run to check the remaining fields

Example fix

// before
default:
  age: "thirty"   # age: Int!

// after
default:
  age: 30

// Field-level context is already attached; log field_name + object_type with the inner error:
if let TypecheckIssue::ObjectTypeField { field_name, object_type, error } = issue {
    eprintln!("{object_type:?}.{field_name}: {error}");
}

When it happens

Trigger: Typechecking an object-typed value where one field's value violates its declared type, e.g. {age: "old"} for an Int field, or a null in a non-null field.

Common situations: Wrong field value types in nested defaults, renamed or retyped object fields leaving stale metadata values, nulls in non-nullable subfields.

Related errors

• Expected an object value of type {expected:} but got value {
• failed to get version from server: %w
• Expected a value of type {expected:} but got value {actual:}
• Error in array item: {inner_error:}
• Expected an array but instead got value {value:}

AI-assisted analysis of hasura/graphql-engine@724551b9ae (2026-08-28). Data as JSON: /api/errors/5521d9f340899a5a. Report an issue: GitHub.