Enum Error 

pub enum Error {
    Wire(Error),
    Storage(Error),
    Tracker(Error),
    Dht(Error),
    Core(Error),
    Connection(String),
    MetadataHashMismatch,
    PieceHashFailed {
        index: u32,
    },
    InvalidPeerData(String),
    TorrentNotFound(Id20),
    DuplicateTorrent(Id20),
    SessionAtCapacity(usize),
    MetadataNotReady(Id20),
    InvalidFileIndex {
        index: usize,
        count: usize,
    },
    FileSkipped {
        index: usize,
    },
    InvalidPieceIndex {
        index: u32,
        num_pieces: u32,
    },
    Config(String),
    InvalidSettings(String),
    Shutdown,
    DhtDisabled,
    PeerReadTimeout(u64),
    PeerDataTimeout(u64),
    PeerWriteTimeout(u64),
    PeerBackpressureOverflow(&'static str),
    I2p(SamError),
    Io(Error),
    CategoryNotFound(String),
    TorrentBeingRemoved(Id20),
    CategoryRegistry(String),
    ConcurrentReconfig,
}

Errors that can occur during session operations.

Variants

Wire(Error)

Wire protocol error from the peer connection layer.

Storage(Error)

Storage/disk I/O error.

Tracker(Error)

Tracker communication error.

Dht(Error)

DHT operation error.

Core(Error)

Core library error (metainfo parsing, hashing, etc.).

Connection(String)

Peer connection failed.

Tuple Fields

0: String

Error description.

MetadataHashMismatch

Received metadata whose info hash does not match the expected value.

PieceHashFailed

A piece failed hash verification.

Fields

index: u32

Zero-based piece index that failed verification.

InvalidPeerData(String)

Received invalid peer data from a tracker or PEX message.

Tuple Fields

0: String

Description of the invalid data.

TorrentNotFound(Id20)

The requested torrent is not in the session.

Tuple Fields

0: Id20

Info hash of the missing torrent.

DuplicateTorrent(Id20)

Attempted to add a torrent that already exists in the session.

Tuple Fields

0: Id20

Info hash of the duplicate torrent.

SessionAtCapacity(usize)

The session has reached its maximum torrent capacity.

Tuple Fields

0: usize

Current number of torrents in the session.

MetadataNotReady(Id20)

Torrent metadata has not been received yet (magnet link still resolving).

Tuple Fields

0: Id20

Info hash of the torrent awaiting metadata.

InvalidFileIndex

File index is out of range for the torrent.

Fields

index: usize

The requested file index.

count: usize

Total number of files in the torrent.

FileSkipped

Attempted to stream a file that has Skip priority.

Fields

index: usize

The file index with Skip priority.

InvalidPieceIndex

Piece index is out of range for the torrent.

Fields

index: u32

The requested piece index.

num_pieces: u32

Total number of pieces in the torrent.

Config(String)

Configuration error (e.g. invalid proxy settings).

Tuple Fields

0: String

Error description.

InvalidSettings(String)

Settings validation failed.

Tuple Fields

0: String

Description of the invalid setting.

Shutdown

The session is shutting down and cannot accept new commands.

DhtDisabled

DHT is disabled in session settings.

PeerReadTimeout(u64)

Peer read timeout — no wire message received within the configured duration.

Tuple Fields

0: u64

Configured timeout in seconds.

PeerDataTimeout(u64)

Peer data contribution timeout — no Piece message received within the configured duration.

Tuple Fields

0: u64

Configured timeout in seconds.

PeerWriteTimeout(u64)

Peer write timeout — outgoing message could not be sent within the configured duration.

Tuple Fields

0: u64

Configured timeout in seconds.

PeerBackpressureOverflow(&'static str)

M182: per-channel backpressure queue exceeded its cap. Treated as a soft stall — the downstream consumer (requester or TorrentActor) is too slow and the wire reader would otherwise stall TCP for all peers on this connection. See M182 audit docs/investigations/2026-05-02-m182-stall-audit/INVESTIGATION.md.

Tuple Fields

0: &'static str

Channel name (dispatch_tx or event_tx).

I2p(SamError)

I2P SAM protocol error.

Io(Error)

Operating system I/O error.

CategoryNotFound(String)

M170: caller specified a category that is not in the registry. The qBt API maps this to 409 Conflict.

Tuple Fields

0: String

The unknown category name.

TorrentBeingRemoved(Id20)

M170: an add arrived while the same info hash is still being removed by a deleteFiles=true delete. Caller should retry shortly. Mapped to 409 Conflict by the qBt API.

Tuple Fields

0: Id20

Info hash currently in the delete grace period.

CategoryRegistry(String)

M170: category registry persistence error.

Tuple Fields

0: String

Error description from the category manager.

ConcurrentReconfig

M173 Lane B (B11): a concurrent apply_settings call won the in-flight guard; this caller must retry shortly. The qBt v2 setPreferences handler maps this to HTTP 409 Conflict.

Trait Implementations

impl Debug for Error

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

Formats the value using the given formatter.

impl Display for Error

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

Formats the value using the given formatter.

impl Error for Error

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 From<Error> for Error

fn from(source: Error) -> Self

Converts to this type from the input type.

impl From<Error> for Error

fn from(source: Error) -> Self

Converts to this type from the input type.

impl From<Error> for Error

fn from(source: Error) -> Self

Converts to this type from the input type.

impl From<Error> for Error

fn from(source: Error) -> Self

Converts to this type from the input type.

impl From<Error> for Error

fn from(source: Error) -> Self

Converts to this type from the input type.

impl From<Error> for Error

fn from(source: Error) -> Self

Converts to this type from the input type.

impl From<SamError> for Error

fn from(source: SamError) -> Self

Converts to this type from the input type.