Enum CacheError 

#[non_exhaustive]
pub enum CacheError {
    Backend(String),
    Unsupported(String),
}

Errors that can occur while interacting with a cache backend.

Marked #[non_exhaustive] as of 0.6.0: match arms must include a _ fallback, and future variants are then additive rather than breaking.

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.

Backend(String)

Unsupported(String)

The backend does not implement the requested operation.

Returned by the shared backends for the tag-index operations (get_keys_by_tag, list_tags, and therefore invalidate_by_tag), which they cannot serve. Reporting it is deliberate: up to 0.5.x they inherited the trait defaults and answered Ok(vec![]) / Ok(0), so a caller could not tell “nothing carried that tag” from “this backend cannot do tags at all”.

Implementations

impl CacheError

pub fn is_unsupported(&self) -> bool

Reports whether this is CacheError::Unsupported.

Trait Implementations

impl Debug for CacheError

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

Formats the value using the given formatter.

impl Display for CacheError

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

Formats the value using the given formatter.

impl Error for CacheError

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.