Enum EngineError 

pub enum EngineError {
    UnknownSource {
        name: String,
        configured: String,
    },
    Token {
        message: String,
    },
    NoSources,
    NotWritable {
        name: String,
        kind: String,
    },
    NoDocuments {
        name: String,
        kind: String,
    },
    DestinationUnavailable {
        name: String,
        error: SourceError,
    },
    NoSuchItem {
        id: String,
    },
    StaleOrigin {
        item: String,
        origin: String,
    },
    SourceRefused {
        name: String,
        error: SourceError,
    },
    CopyNotUndone {
        error: Box<EngineError>,
        left_behind: LeftBehind,
        refusal: SourceError,
    },
}

What the engine refuses before it asks any source.

Distinct from a SourceFailure, which is one source failing while the others answer: everything here means the request itself cannot be run at all.

Eq is deliberately absent: three variants carry the SourceError the source itself gave, which is what a user has to act on, and that type is PartialEq alone.

Variants

UnknownSource

A --source named something no configuration configures.

Fields

name: String

The name that was asked for.

configured: String

The names that exist, for the message.

Token

A --page token that decodes but does not belong to this query.

Fields

message: String

What the token claims that this configuration cannot honour.

NoSources

Nothing at all is configured, so there is nothing to ask.

NotWritable

A copy named a destination whose plugin has no write side.

Fields

name: String

The configured name of the destination.

kind: String

The plugin behind it.

NoDocuments

A document read or write named a source whose plugin has no documents.

The same shape NotWritable has, and for the same reason: the declaration is read once at the handshake, so a source that says it has no documents is refused before anything is read rather than asked and then apologised for.

Fields

name: String

The configured name of the source.

kind: String

The plugin behind it.

DestinationUnavailable

A copy named a destination that is configured but could not be built.

Fields

name: String

The configured name of the destination.

error: SourceError

Why it did not build.

NoSuchItem

A copy named an id its own source does not hold.

Fields

id: String

The qualified id that named nothing.

StaleOrigin

An item’s recorded origin names an item the destination no longer holds.

Refused rather than created: the destination item was deleted or moved on purpose, and creating a second one there would duplicate work somebody removed.

Fields

item: String

The item being copied.

origin: String

The origin it records.

SourceRefused

A source refused something the copy asked of it.

Distinct from a SourceFailure, which leaves the other sources’ results standing: a copy is one write into one destination, and half of one is not an answer.

Fields

name: String

The source that refused.

error: SourceError

What it said.

CopyNotUndone

A copy failed, and the destination could not be put back the way it was found.

A copy is either complete or it never happened, and the engine undoes its own writes to make that true. When the destination will not take one of them back, the failure has to say so and name what is still there: a user told only that the copy failed would copy again over a destination nobody has described to them, which is the retry that trips a hosted destination’s rate limiter.

Fields

error: Box<EngineError>

Why the copy failed in the first place.

left_behind: LeftBehind

The items the copy created or overwrote and could not take back.

The ids themselves rather than a sentence about them: a caller acting on this — removing them, or reporting them — needs the ids, and the joined form only the message needs is LeftBehind’s own Display.

refusal: SourceError

What the destination said when the copy tried to take them back.

Trait Implementations

impl Clone for EngineError

fn clone(&self) -> EngineError

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for EngineError

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

Formats the value using the given formatter.

impl Display for EngineError

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

Formats the value using the given formatter.

impl Error for EngineError

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.

impl PartialEq for EngineError

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for EngineError