Enum Class 

#[non_exhaustive]
pub enum Class {
    Cancelled,
    Corruption,
    ResourceExhaustion(ResourceExhaustionKind),
    Validation,
    Unsupported,
    Unauthenticated,
    PermissionDenied,
    Conflict,
    NotFound,
    Retryable,
}

The recovery approach suggested by an error.

Variants are listed in suggested recovery precedence, highest first; smaller values have higher precedence under Ord. crate::Error::dominant_class() selects the smallest class present in the error tree. When multiple classes are present, check earlier variants before later ones: cancellation means stop, while retryability alone does not override a failure that needs another remedy. Adapt this precedence to the operation and its concrete errors. Classification iterators retain error traversal order, not this precedence, and class predicates report presence independently rather than suppressing lower-priority classes.

A class guides recovery, but does not establish that it is safe. Inspect concrete errors and partial outcomes before repeating operations with side effects; see recovery.

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.

Cancelled

The caller requested cancellation; stop rather than retry.

Corruption

Stored or streamed data was malformed or internally inconsistent.

Recovery may require repairing, replacing, or re-fetching the data, rather than correcting the caller’s input.

ResourceExhaustion(ResourceExhaustionKind)

A finite resource was exhausted.

Recovery may require reducing resource use or making more capacity available before retrying. The kind distinguishes an application-configured allocation limit from an allocation failure, so callers can choose whether to adjust a limit or address the allocation itself.

Validation

Function or method input was invalid.

Recovery requires correcting the input rather than retrying the same request unchanged.

Unsupported

A required capability is unsupported; switch implementation, format, protocol, or strategy.

Unauthenticated

Credentials are missing or rejected; obtain or refresh credentials.

PermissionDenied

Authorization or permissions are insufficient; obtain authorization or change permissions.

Conflict

Current state conflicts with the operation; refresh or reconcile state before retrying.

NotFound

A requested resource does not exist.

Callers may recover by creating the resource, using a fallback, or treating absence as an expected outcome. This distinguishes absence from failures that prevent determining whether the resource exists.

Retryable

Retrying the operation may succeed.

Callers may recover with a bounded retry, possibly after waiting, without changing the request. This is not a guarantee of success or a statement that repeating an operation with side effects is safe.

Trait Implementations

impl Clone for Class

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for Class

impl Debug for Class

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

Formats the value using the given formatter.

impl Eq for Class

impl Ord for Class

fn cmp(&self, other: &Self) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

fn clamp_to<R>(self, range: R) -> Self

where Self: Sized, R: ClampBounds<Self>,

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

Restrict a value to a certain range.

impl PartialEq for Class

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

Equality operator ==.

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

Inequality operator !=.

impl PartialOrd for Class

fn partial_cmp(&self, other: &Self) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

Tests less than (for self and other) and is used by the < operator.

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

Tests less than or equal to (for self and other) and is used by the <= operator.

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

Tests greater than (for self and other) and is used by the > operator.

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

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl StructuralPartialEq for Class