Enum BackendError 

#[non_exhaustive]
pub enum BackendError {
    Valkey {
        kind: BackendErrorKind,
        message: String,
    },
    RequiresDevMode,
}

Backend-agnostic transport error carried across public ff-sdk / ff-server error surfaces (#88).

The Valkey variant is the only one populated today; additional variants (e.g. Postgres) will be added additively as other backends land. The enum is #[non_exhaustive] so consumers must include a wildcard arm.

Construction from the Valkey-native ferriskey::Error lives in ff_backend_valkey::backend_error_from_ferriskey — keeping that conversion outside ff-core preserves ff-core’s ferriskey-free public surface.

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.

Valkey

Valkey-backend transport failure. Carries a backend-agnostic classification plus the backend-rendered message so downstream consumers can inspect without depending on ferriskey.

Fields

kind: BackendErrorKind

message: String

RequiresDevMode

RFC-023 §4.5: the SQLite dev-only backend refused to construct because FF_DEV_MODE=1 was not set. Exact message text mirrors §3.3 HTTP-path text so embedded and server paths give the same actionable signal.

Implementations

impl BackendError

pub fn kind(&self) -> BackendErrorKind

Returns the classified backend kind.

Every variant maps to a BackendErrorKind — transport variants return their carried kind, configuration/guard variants return the closest-fitting classification (e.g. BackendError::RequiresDevMode → BackendErrorKind::Protocol because it is a configuration refusal, not a retryable transport fault). Consumers needing to distinguish the underlying variant should match directly on BackendError; kind() is the stable, classifier-only view.

pub fn message(&self) -> &str

Return the backend-rendered message payload.

Trait Implementations

impl Clone for BackendError

fn clone(&self) -> BackendError

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for BackendError

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

Formats the value using the given formatter.

impl Display for BackendError

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

Formats the value using the given formatter.

impl Error for BackendError

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.