Enum ProjectionError 

#[non_exhaustive]
pub enum ProjectionError {
    SequenceBackward {
        last: ProjectionCursor,
        incoming: ProjectionCursor,
    },
    SequenceGap {
        last: ProjectionCursor,
        incoming: ProjectionCursor,
    },
    PositionConflict {
        at: ProjectionCursor,
    },
    NotActive {
        state: ObserverState,
    },
    Storage(&'static str),
    DecodeFailed(&'static str),
    MissingRow,
}

Projection-side failure taxonomy.

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.

SequenceBackward

The event stream moved backward (corruption, mis-ordered redelivery, or two computes sharing one tick — see ProjectionRouter::dispatch).

Fields

last: ProjectionCursor

Stream head the incoming event was ordered against — the last accepted event or, when a failed dispatch is awaiting retry, the pinned unapplied position.

incoming: ProjectionCursor

Position of the rejected incoming event.

SequenceGap

The stream skipped an event — a same-tick sequence jump, or a new tick whose batch does not start at sequence 0. The replay harness needs to fetch the missing range before dispatch can advance.

Fields

last: ProjectionCursor

Stream head the incoming event was ordered against — the last accepted event or, when a failed dispatch is awaiting retry, the pinned unapplied position.

incoming: ProjectionCursor

Position of the event that exposed the gap.

PositionConflict

A DIFFERENT event arrived at a position the router has already pinned — the accepted cursor position, or a failed dispatch’s pending-retry pin. Two same-tick computes collided on the (tick, sequence) identity (driver contract violation), distinguished from a true redelivery/retry by event identity (type code + payload).

Fields

at: ProjectionCursor

The contested stream position.

NotActive

Caller attempted a mutation in a non-Active state (observer is Passive or Draining).

Fields

state: ObserverState

Observer state at the time of the attempted mutation.

Storage(&'static str)

Storage-layer error (in-memory corruption, PG driver, …).

DecodeFailed(&'static str)

Event payload failed to decode.

MissingRow

An event targeted an Actor / Space / Entry / Activity that the projection has no row for.

Trait Implementations

impl Debug for ProjectionError

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

Formats the value using the given formatter.

impl Display for ProjectionError

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

Formats the value using the given formatter.

impl Error for ProjectionError

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.