Enum Error 

#[non_exhaustive]
pub enum Error {
    Message {
        msg: String,
        location: Location,
    },
    ExternalMessage {
        source: ExternalMessageSource,
        msg: String,
        code: Option<String>,
        params: Vec<(String, String)>,
        location: Location,
    },
    Eof {
        location: Location,
    },
    MultipleDocuments {
        hint: &'static str,
        location: Location,
    },
    Unexpected {
        expected: &'static str,
        location: Location,
    },
    MergeValueNotMapOrSeqOfMaps {
        location: Location,
    },
    InvalidBinaryBase64 {
        location: Location,
    },
    BinaryNotUtf8 {
        location: Location,
    },
    TaggedScalarCannotDeserializeIntoString {
        location: Location,
    },
    UnexpectedSequenceEnd {
        location: Location,
    },
    UnexpectedMappingEnd {
        location: Location,
    },
    InvalidBooleanStrict {
        location: Location,
    },
    InvalidCharNull {
        location: Location,
    },
    InvalidCharNotSingleScalar {
        location: Location,
    },
    NullIntoString {
        location: Location,
    },
    BytesNotSupportedMissingBinaryTag {
        location: Location,
    },
    UnexpectedValueForUnit {
        location: Location,
    },
    ExpectedEmptyMappingForUnitStruct {
        location: Location,
    },
    UnexpectedContainerEndWhileSkippingNode {
        location: Location,
    },
    InternalSeedReusedForMapKey {
        location: Location,
    },
    ValueRequestedBeforeKey {
        location: Location,
    },
    ExpectedStringKeyForExternallyTaggedEnum {
        location: Location,
    },
    ExternallyTaggedEnumExpectedScalarOrMapping {
        location: Location,
    },
    UnexpectedValueForUnitEnumVariant {
        location: Location,
    },
    InvalidUtf8Input,
    AliasReplayCounterOverflow {
        location: Location,
    },
    AliasReplayLimitExceeded {
        total_replayed_events: usize,
        max_total_replayed_events: usize,
        location: Location,
    },
    AliasExpansionLimitExceeded {
        anchor_id: usize,
        expansions: usize,
        max_expansions_per_anchor: usize,
        location: Location,
    },
    AliasReplayStackDepthExceeded {
        depth: usize,
        max_depth: usize,
        location: Location,
    },
    FoldedBlockScalarMustIndentContent {
        location: Location,
    },
    InternalDepthUnderflow {
        location: Location,
    },
    InternalRecursionStackEmpty {
        location: Location,
    },
    RecursiveReferencesRequireWeakTypes {
        location: Location,
    },
    InvalidScalar {
        ty: &'static str,
        location: Location,
    },
    SerdeInvalidType {
        unexpected: String,
        expected: String,
        location: Location,
    },
    SerdeInvalidValue {
        unexpected: String,
        expected: String,
        location: Location,
    },
    SerdeUnknownVariant {
        variant: String,
        expected: Vec<&'static str>,
        location: Location,
    },
    SerdeUnknownField {
        field: String,
        expected: Vec<&'static str>,
        location: Location,
    },
    SerdeMissingField {
        field: &'static str,
        location: Location,
    },
    UnexpectedContainerEndWhileReadingKeyNode {
        location: Location,
    },
    DuplicateMappingKey {
        key: Option<String>,
        location: Location,
    },
    TaggedEnumMismatch {
        tagged: String,
        target: &'static str,
        location: Location,
    },
    SerdeVariantId {
        msg: String,
        location: Location,
    },
    ExpectedMappingEndAfterEnumVariantValue {
        location: Location,
    },
    ContainerEndMismatch {
        location: Location,
    },
    UnknownAnchor {
        location: Location,
    },
    AliasError {
        msg: String,
        locations: Locations,
    },
    HookError {
        msg: String,
        location: Location,
    },
    Budget {
        breach: BudgetBreach,
        location: Location,
    },
    IOError {
        cause: Error,
    },
    QuotingRequired {
        value: String,
        location: Location,
    },
    CannotBorrowTransformedString {
        reason: TransformReason,
        location: Location,
    },
    WithSnippet {
        regions: Vec<CroppedRegion>,
        crop_radius: usize,
        error: Box<Error>,
    },
    ValidationError {
        report: Report,
        locations: PathMap,
    },
    ValidationErrors {
        errors: Vec<Error>,
    },
    ValidatorError {
        errors: ValidationErrors,
        locations: PathMap,
    },
    ValidatorErrors {
        errors: Vec<Error>,
    },
}

Error type compatible with serde::de::Error.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

Message

Free-form error with optional source location.

Fields

msg: String

location: Location

ExternalMessage

Text primarily produced by a dependency (parser / validators).

Renderers should call Localizer::override_external_message to allow callers to replace or translate this text.

Fields

source: ExternalMessageSource

msg: String

code: Option<String>

Stable-ish identifier when available (e.g. validator error code).

params: Vec<(String, String)>

Optional structured parameters when available.

location: Location

Eof

Unexpected end of input.

Fields

location: Location

MultipleDocuments

More than one YAML document was found when a single document was expected.

This is typically returned by single-document entrypoints like from_str* / from_slice* / read_to_end* when the input stream contains multiple ----delimited documents.

Fields

hint: &'static str

Developer-facing hint (may mention specific APIs).

location: Location

Unexpected

Structural/type mismatch — something else than the expected token/value was seen.

Fields

expected: &'static str

location: Location

MergeValueNotMapOrSeqOfMaps

YAML merge (<<) value was not a mapping or a sequence of mappings.

Fields

location: Location

InvalidBinaryBase64

!!binary scalar could not be decoded as base64.

Fields

location: Location

BinaryNotUtf8

!!binary scalar decoded successfully but was not valid UTF-8 when a string was expected.

Fields

location: Location

TaggedScalarCannotDeserializeIntoString

A scalar was explicitly tagged but could not be deserialized into a string.

Fields

location: Location

UnexpectedSequenceEnd

Encountered a sequence end where it was not expected.

Fields

location: Location

UnexpectedMappingEnd

Encountered a mapping end where it was not expected.

Fields

location: Location

InvalidBooleanStrict

Invalid boolean literal in strict mode.

Fields

location: Location

InvalidCharNull

Invalid char: null cannot be deserialized into char.

Fields

location: Location

InvalidCharNotSingleScalar

Invalid char: expected a single Unicode scalar value.

Fields

location: Location

NullIntoString

Cannot deserialize null into string.

Fields

location: Location

BytesNotSupportedMissingBinaryTag

Bytes (&[u8] / Vec<u8>) are not supported unless the scalar is tagged as !!binary.

Fields

location: Location

UnexpectedValueForUnit

Unexpected value for unit (()).

Fields

location: Location

ExpectedEmptyMappingForUnitStruct

Unit struct expected an empty mapping.

Fields

location: Location

UnexpectedContainerEndWhileSkippingNode

While skipping a node, a container end event was encountered unexpectedly.

Fields

location: Location

InternalSeedReusedForMapKey

Internal error: a seed was reused for a map key.

Fields

location: Location

ValueRequestedBeforeKey

Internal error: value requested before key.

Fields

location: Location

ExpectedStringKeyForExternallyTaggedEnum

Externally tagged enum: expected a string key.

Fields

location: Location

ExternallyTaggedEnumExpectedScalarOrMapping

Externally tagged enum: expected either a scalar or a mapping.

Fields

location: Location

UnexpectedValueForUnitEnumVariant

Unexpected value for unit enum variant.

Fields

location: Location

InvalidUtf8Input

Input was not valid UTF-8.

AliasReplayCounterOverflow

Alias replay counter overflow.

Fields

location: Location

AliasReplayLimitExceeded

Alias replay total event limit exceeded.

Fields

total_replayed_events: usize

max_total_replayed_events: usize

location: Location

AliasExpansionLimitExceeded

Alias expansion limit exceeded for a single anchor.

Fields

anchor_id: usize

expansions: usize

max_expansions_per_anchor: usize

location: Location

AliasReplayStackDepthExceeded

Alias replay stack depth limit exceeded.

Fields

depth: usize

max_depth: usize

location: Location

FoldedBlockScalarMustIndentContent

Folded block scalars must indent their content.

Fields

location: Location

InternalDepthUnderflow

Internal: depth counter underflow.

Fields

location: Location

InternalRecursionStackEmpty

Internal: recursion stack empty.

Fields

location: Location

RecursiveReferencesRequireWeakTypes

recursive references require weak recursion types.

Fields

location: Location

InvalidScalar

Scalar parsing failed for the requested target type.

Fields

ty: &'static str

location: Location

SerdeInvalidType

Serde-generated: invalid type.

Fields

unexpected: String

expected: String

location: Location

SerdeInvalidValue

Serde-generated: invalid value.

Fields

unexpected: String

expected: String

location: Location

SerdeUnknownVariant

Serde-generated: unknown enum variant.

Fields

variant: String

expected: Vec<&'static str>

location: Location

SerdeUnknownField

Serde-generated: unknown field.

Fields

field: String

expected: Vec<&'static str>

location: Location

SerdeMissingField

Serde-generated: missing required field.

Fields

field: &'static str

location: Location

UnexpectedContainerEndWhileReadingKeyNode

Encountered the end of a sequence or mapping while reading a key node.

This indicates a structural mismatch in the input.

Fields

location: Location

DuplicateMappingKey

Duplicate key in a mapping.

When the duplicate key can be rendered as a string-like scalar, key is provided.

Fields

key: Option<String>

location: Location

TaggedEnumMismatch

Tagged enum name does not match the target enum.

Fields

tagged: String

target: &'static str

location: Location

SerdeVariantId

Serde-generated error while deserializing an enum variant identifier.

Fields

msg: String

location: Location

ExpectedMappingEndAfterEnumVariantValue

Expected the end of a mapping after an externally tagged enum variant value.

Fields

location: Location

ContainerEndMismatch

Fields

location: Location

UnknownAnchor

Alias references a non-existent anchor.

Fields

location: Location

AliasError

Error related to an alias, with both reference (use-site) and defined (anchor) locations.

This variant allows reporting both where an alias is used and where the anchor is defined, which is useful for errors that occur when deserializing aliased values.

Fields

msg: String

locations: Locations

HookError

Error when parsing robotic and other extensions beyond standard YAML. (error in extension hook).

Fields

msg: String

location: Location

Budget

A YAML budget limit was exceeded.

Fields

breach: BudgetBreach

location: Location

IOError

Unexpected I/O error. This may happen only when deserializing from a reader.

Fields

cause: Error

QuotingRequired

The value is targeted to the string field but can be interpreted as a number or boolean. This error can only happen if no_schema set true.

Fields

value: String

location: Location

CannotBorrowTransformedString

The target type requires a borrowed string (&str), but the value was transformed during parsing (e.g., through escape processing, line folding, or multi-line normalization) and cannot be borrowed from the input.

Use String or Cow<str> instead of &str to handle transformed values.

Fields

reason: TransformReason

The reason why the string had to be transformed and cannot be borrowed.

location: Location

WithSnippet

Wrap an error with the full input text, enabling rustc-like snippet rendering.

Fields

regions: Vec<CroppedRegion>

Cropped source windows used for snippet rendering.

This intentionally does NOT store the full input text, to avoid retaining large YAML inputs inside errors.

crop_radius: usize

error: Box<Error>

ValidationError

Garde validation failure.

Fields

report: Report

locations: PathMap

ValidationErrors

Garde validation failures (multiple, if multiple validations fail)

Fields

errors: Vec<Error>

ValidatorError

Validator validation failure.

Fields

errors: ValidationErrors

locations: PathMap

ValidatorErrors

Validator validation failures (multiple, if multiple validations fail)

Fields

errors: Vec<Error>

Implementations

impl Error

pub fn without_snippet(&self) -> &Self

Provide “no snippet” version for cases when snippet rendering is not desired.

pub fn render(&self) -> String

Render this error using the built-in developer formatter.

This is the deferred-rendering entrypoint. It is equivalent to Display/to_string() output, but also allows callers to choose a custom MessageFormatter via Error::render_with_options.

pub fn render_with_formatter(&self, formatter: &dyn MessageFormatter) -> String

Render this error using a custom message formatter.

pub fn render_with_options(&self, options: RenderOptions<'_>) -> String

Render this error using the provided options.

pub fn cannot_borrow_transformed(reason: TransformReason) -> Self

Construct a CannotBorrowTransformedString error for the given reason.

This error is returned when deserializing to &str but the string value was transformed during parsing and cannot be borrowed from the input.

pub fn location(&self) -> Option<Location>

If the error has a known location, return it.

Returns:

• Some(Location) when coordinates are known; None otherwise.

Used by:

• Callers that want to surface precise positions to users.

pub fn locations(&self) -> Option<Locations>

Return a pair of locations associated with this error.

• For syntax and other errors that carry a single Location, this returns two identical locations.

• For validation errors (when the garde / validator feature is enabled), this returns the (reference_location, defined_location) pair for the first validation entry.

  These two locations may differ when YAML anchors/aliases are involved.

• Returns None when no meaningful location information is available.

Trait Implementations

impl Debug for Error

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

Formats the value using the given formatter.

impl Display for Error

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

Formats the value using the given formatter.

impl Error for Error

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 Error for Error

fn custom<T: Display>(msg: T) -> Self

Raised when there is general error when deserializing a type.

fn invalid_type(unexp: Unexpected<'_>, exp: &dyn Expected) -> Self

Raised when a Deserialize receives a type different from what it was expecting.

fn invalid_value(unexp: Unexpected<'_>, exp: &dyn Expected) -> Self

Raised when a Deserialize receives a value of the right type but that is wrong for some other reason.

fn unknown_variant(variant: &str, expected: &'static [&'static str]) -> Self

Raised when a Deserialize enum type received a variant with an unrecognized name.

fn unknown_field(field: &str, expected: &'static [&'static str]) -> Self

Raised when a Deserialize struct type received a field with an unrecognized name.

fn missing_field(field: &'static str) -> Self

Raised when a Deserialize struct type expected to receive a required field with a particular name but that field was not present in the input.

fn invalid_length(len: usize, exp: &dyn Expected) -> Self

Raised when deserializing a sequence or map and the input data contains too many or too few elements.

fn duplicate_field(field: &'static str) -> Self

Raised when a Deserialize struct type received more than one of the same field.