Enum ValidationError 

#[non_exhaustive]
pub enum ValidationError {
    Empty {
        field: &'static str,
    },
    MissingField(&'static str),
    TooLong {
        field: &'static str,
        observed: usize,
        limit: usize,
    },
    BadChar {
        field: &'static str,
        byte: u8,
        offset: usize,
    },
    Shape {
        field: &'static str,
        rule: &'static str,
    },
    Range {
        field: &'static str,
        min: i64,
        max: i64,
        got: i64,
    },
}

Reasons a validated newtype constructor (e.g. crate::Address::new) can reject its input.

Field names are stable; new variants are additive.

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.

Empty

The candidate string was empty when a non-empty value was required.

Fields

field: &'static str

Name of the field being validated.

MissingField(&'static str)

A required builder field was not set before crate::Parser::builder finalisation. The string is the field name (e.g. "workspace_root").

TooLong

The candidate exceeds the per-field byte cap.

Fields

field: &'static str

Name of the field being validated.

observed: usize

Observed byte length.

limit: usize

Configured maximum.

BadChar

A disallowed character appeared in the candidate.

Fields

field: &'static str

Name of the field being validated.

byte: u8

Offending byte (rendered as a char in the message).

offset: usize

Byte offset of the offending character.

Shape

The candidate failed a higher-level structural rule (balanced quotes/brackets, expected digit count, etc.). rule is a short machine-readable token (e.g. "unbalanced-brackets"); the message embeds the input snippet for diagnostics.

Fields

field: &'static str

Name of the field being validated.

rule: &'static str

Rule identifier — short machine-readable token.

Range

The candidate falls outside an allowed numeric range. Use for integer-shaped invariants — codec levels, percentages, port numbers.

Fields

field: &'static str

Name of the field being validated.

min: i64

Inclusive minimum.

max: i64

Inclusive maximum.

got: i64

Observed value.

Trait Implementations

impl Debug for ValidationError

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

Formats the value using the given formatter.

impl Display for ValidationError

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

Formats the value using the given formatter.

impl Error for ValidationError

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 From<ValidationError> for Error

fn from(source: ValidationError) -> Self

Converts to this type from the input type.