Enum ApplyError 

pub enum ApplyError {
    ValidationFailed(String),
    ListenPortInUse {
        attempted: u16,
        existing: u16,
    },
    DhtRestartFailed(String),
    LsdRestartFailed(String),
    NatRefreshFailed(String),
    ConcurrentReconfig,
    Io(String),
}

Errors that can be returned by the transactional apply_settings path.

Covers validation failure, listener bind failure, sub-actor restart failures, NAT refresh failure, and concurrent reconfig collision. Each variant is mapped onto an HTTP status by the qBt v2 setPreferences handler — see ApplyError::http_status.

Variants

ValidationFailed(String)

Settings::validate() rejected the new settings.

ListenPortInUse

The new listen_port is already in use (typically EADDRINUSE). attempted is the port we tried to bind; existing is the port the session is still listening on (rolled back).

Fields

attempted: u16

The port that failed to bind.

existing: u16

The port the session is still listening on.

DhtRestartFailed(String)

DHT enable/disable failed.

LsdRestartFailed(String)

LSD enable/disable failed.

NatRefreshFailed(String)

NAT mapping refresh failed.

NOT FATAL when wrapped — see ApplyError::is_fatal. Logged as a warning; the session continues with the new listen_port but without router-side mapping.

ConcurrentReconfig

A second setPreferences (or other reconfig) raced this one and won the in-flight guard. Caller should retry; the previous call’s effect is observable via a follow-up getSettings query.

Mapped to HTTP 409 Conflict by the qBt v2 setPreferences handler.

Io(String)

A subsystem operation produced a generic I/O error.

Implementations

impl ApplyError

pub fn http_status(&self) -> u16

Map this error onto the HTTP status the qBt v2 setPreferences handler should return.

• ValidationFailed → 400 Bad Request.
• ListenPortInUse → 409 Conflict (port collision is recoverable).
• ConcurrentReconfig → 409 Conflict (another caller raced).
• DhtRestartFailed / LsdRestartFailed → 500 Internal.
• NatRefreshFailed → 200 OK (non-fatal — caller proceeds; only the warning header tells them mapping refresh missed).
• Io → 500 Internal.

pub const fn is_fatal(&self) -> bool

True if this error indicates the session is in a degraded state after rollback (i.e. rollback itself failed).

B1 currently always returns false; M174+ will introduce a “session degraded” mode for unrecoverable rollback faults.

Trait Implementations

impl Debug for ApplyError

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

Formats the value using the given formatter.

impl Display for ApplyError

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

Formats the value using the given formatter.

impl Error for ApplyError

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.