Enum TransportError 

#[non_exhaustive]
pub enum TransportError {
    Connect {
        target: String,
        source: Box<dyn Error + Send + Sync>,
    },
    ConnectionLost {
        reason: String,
    },
    Send {
        name: &'static str,
        reason: String,
    },
    MalformedFrame {
        reason: String,
    },
    Capacity {
        limit_bytes: usize,
        reason: String,
    },
}

Something went wrong moving bytes. Carries no protocol meaning.

This type belongs to the public taxonomy, not to a transport. It is defined here, beside Error, because the distinction it draws is one a caller can act on — failing to connect and losing an established stream call for different responses — and because a type in this crate’s semver promise must be owned by the module that makes that promise. The transports themselves stay private and merely produce these; adding one is not a semver event (docs/adr/0007-transport-port-shape.md), and it must not become one by an adapter widening this enum on its own account.

On the cause of TransportError::Connect

It is a Box<dyn Error> rather than a named type so that no dependency’s semantic version becomes part of this crate’s. Read it, log it, print its chain — but do not downcast it: which concrete error arrives there depends on which transport ran and on the version of the crate underneath it, and neither is part of the promise made here. Everything worth branching on is the variant.

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.

Connect

The connection could not be established.

Fields

target: String

What was being connected to. Never carries userinfo: an address with a user:password@ prefix is refused at configuration time, and what reaches here is redacted regardless.

source: Box<dyn Error + Send + Sync>

The underlying failure. Opaque by design — see the type docs.

ConnectionLost

The connection failed or was dropped while in use.

This is transition T5 [docs/spec/02-session-lifecycle.md §2.2]: no notification is received, the session is not closed, and the client is still entitled to attempt recovery.

Fields

reason: String

What ended it.

Send

A control request could not be delivered.

Fields

name: &'static str

The request name, as TLCP spells it — control, msg, heartbeat [docs/spec/03-requests.md §1].

reason: String

What went wrong.

MalformedFrame

The peer sent a frame that cannot be turned into TLCP lines — a binary WebSocket message, or bytes that are not valid UTF-8.

Fields

reason: String

What was wrong with it.

Capacity

The peer sent more than this client is willing to buffer for it.

Every dimension a server controls is capped, because a client that allocates whatever it is told to is one malformed stream away from taking its process with it. The connection is not usable afterwards: what was buffered has been discarded, so the line stream has a hole in it and the session must be recovered rather than resumed.

Fields

limit_bytes: usize

The ceiling that was exceeded.

reason: String

What exceeded it. Never contains a credential.

Trait Implementations

impl Debug for TransportError

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

Formats the value using the given formatter.

impl Display for TransportError

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

Formats the value using the given formatter.

impl Error for TransportError

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<TransportError> for Error

fn from(source: TransportError) -> Self

Converts to this type from the input type.