Enum TaskStoreError 

#[non_exhaustive]
pub enum TaskStoreError {
    Encode(String),
    Decode(String),
    Backend(String),
    InvalidTransition(String),
    RetentionLimitExceeded {
        kind: TaskRetentionLimitKind,
        limit: usize,
    },
}

Errors returned by TaskStore implementations.

Encode and decode errors come from (de)serializing task state, and Backend is the catch-all for the storage layer. Those three mirror SessionStoreError and exist for external implementations; MemoryTaskStore never returns them.

InvalidTransition is different in kind. It reports that the requested change is not legal for the task’s current state, which is deterministic and says nothing about storage health, so a caller must not treat it as retryable. MemoryTaskStore does return it (#1246).

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.

Encode(String)

Failed to encode task state (e.g. serde serialization error).

Decode(String)

Failed to decode task state (e.g. corrupt data in the backend).

Backend(String)

Backend error (e.g. connection failure, transient storage error).

InvalidTransition(String)

The requested change is not valid for the task’s current state.

Deterministic: the same call fails the same way, so retrying cannot help and callers should not confuse it with an infrastructure failure. Reusing an input request key is the current instance (#1246).

RetentionLimitExceeded

A configured task-retention limit rejected a mutation.

The error carries only the limit category and numeric bound. It never includes the rejected arguments, input, result, or error payload, so it is safe to map, log, or expose through a host’s error policy.

Fields

kind: TaskRetentionLimitKind

Limit that rejected the operation.

limit: usize

Configured maximum for that limit.

Trait Implementations

impl Debug for TaskStoreError

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

Formats the value using the given formatter.

impl Display for TaskStoreError

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

Formats the value using the given formatter.

impl Error for TaskStoreError

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.