Struct BodyValidationError 

pub struct BodyValidationError {
    pub expected_type: String,
    pub field_path: String,
    pub expected: String,
    pub got: String,
    pub hint: String,
    pub expected_cardinality: String,
    pub got_cardinality: String,
    pub got_length: Option<u64>,
    pub remediation_url: String,
}

Structured body-validation error. The HTTP layer projects this into a 400 Bad Request with the field/expected/got triple so adopter clients can correct their request without server-side log diving.

Fields

expected_type: String

Top-level body type the validation was attempted against (e.g. "LoanApplication").

field_path: String

Dotted path to the offending field: "applicant.address.street" for nested structures, "[2].name" for list-element index 2. Empty string when the violation is at the top-level body itself (e.g. expected object, got string).

expected: String

Declared type the validator expected.

got: String

JSON-type tag observed ("string", "number", "integer", "boolean", "array", "object", "null", "missing").

hint: String

Adopter-facing diagnostic — full sentence with a corrective hint. Stable across versions per D8 backwards-compat surface.

expected_cardinality: String

§Fase 38.x.f (D2) — Declared cardinality kind of the expected type: "singular" | "plural" | "stream" | "unit" | "unknown". Empty string for primitive-type validation errors where the cardinality isn’t load-bearing (the existing v1.39.0 surface). Serde #[serde(default)] keeps adopter consumers of older versions byte-compatible.

got_cardinality: String

§Fase 38.x.f (D2) — Observed cardinality kind of the response body: same alphabet as expected_cardinality. Empty when not applicable. The asymmetry expected/got is the diagnostic payload adopters reach for first when D5 fires.

got_length: Option<u64>

§Fase 38.x.f (D2) — Length of the observed value when it is array (plural). None for non-array gots. Helps adopters confirm “the flow returned 1 row, but the contract said singular — collapse with result[0] or change the endpoint to output: List<T>”.

remediation_url: String

§Fase 38.x.f (D2) — Documentation URL adopters can follow for the canonical remediation steps. Empty when the error is not a cardinality mismatch (the existing v1.39.0 surface). The URL is stable; the page may evolve.

Trait Implementations

impl Clone for BodyValidationError

fn clone(&self) -> BodyValidationError

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for BodyValidationError

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for BodyValidationError

fn default() -> BodyValidationError

Returns the “default value” for a type.

impl Display for BodyValidationError

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Error for BodyValidationError

fn source(&self) -> Option<&(dyn Error + 'static)>

Returns the lower-level source of this error, if any.

fn description(&self) -> &str

👎Deprecated since 1.42.0:

use the Display impl or to_string()

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

fn provide<'a>(&'a self, request: &mut Request<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access)

Provides type-based access to context intended for error reports.

impl PartialEq for BodyValidationError

fn eq(&self, other: &BodyValidationError) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for BodyValidationError

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for BodyValidationError