Enum IdempotencyClaim 

#[non_exhaustive]
pub enum IdempotencyClaim {
    Claimed,
    Replay(TaskId),
    Conflict {
        held_by: MessageId,
    },
}

What happened when a store was asked to claim an idempotency key.

See TaskStore::claim_idempotency_key.

#[non_exhaustive] because every out-of-tree TaskStore must match on this, and the outcomes this can report are not a closed set: an expiry, or an “in flight, wait” that would let the second caller be told to retry instead of handed a TaskNotFound, are both plausible fourth variants. Adding one without the attribute would be a compile break for every external store — which STABILITY.md §4 promises not to inflict.

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.

Claimed

The key was free. The caller owns it and should create the task.

Replay(TaskId)

The key is already held, by the same message. A genuine retry: return the named task in whatever state it has reached, and execute nothing.

Conflict

The key is already held, by a different message.

Not a retry. Either the caller generated one key for two distinct sends, or two of its concurrent sends collided on a key. Returning the first task here would hand back a result for a message the caller did not just send, and it would act on it — a silent wrong answer, the failure a caller can least detect. It is reported instead.

Fields

held_by: MessageId

The message holding the key, named in the error the caller sees.

Trait Implementations

impl Clone for IdempotencyClaim

fn clone(&self) -> IdempotencyClaim

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for IdempotencyClaim

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

Formats the value using the given formatter.

impl Eq for IdempotencyClaim

impl PartialEq for IdempotencyClaim

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for IdempotencyClaim