Enum SessionError 

pub enum SessionError {
    WebTransport(Error),
    Encode(EncodeError),
    Decode(DecodeError),
    Version(Versions, Versions),
    RoleViolation,
    BoundsExceeded(BoundsExceeded),
    Duplicate,
    Internal,
    Serve(ServeError),
    WrongSize,
}

Variants

WebTransport(Error)

Encode(EncodeError)

Decode(DecodeError)

Version(Versions, Versions)

RoleViolation

TODO SLG - eventually remove or morph into error for incorrect control message for publisher/subscriber The role negiotiated in the handshake was violated. For example, a publisher sent a SUBSCRIBE, or a subscriber sent an OBJECT.

BoundsExceeded(BoundsExceeded)

Some VarInt was too large and we were too lazy to handle it

Duplicate

A duplicate ID was used

Internal

Serve(ServeError)

WrongSize

Implementations

impl SessionError

pub fn code(&self) -> u64

An integer code that is sent over the wire. Returns Session Termination Error Codes per draft-14.

pub fn unimplemented(feature: &str) -> Self

Helper for unimplemented protocol features Logs a warning and returns a NotImplemented error instead of panicking

pub fn is_graceful_close(&self) -> bool

Returns true if this error represents a graceful connection close.

For WebTransport, a graceful close is a CLOSE_WEBTRANSPORT_SESSION capsule with code 0. For raw QUIC, it’s APPLICATION_CLOSE with code 0 (NO_ERROR). Both are normal session termination, not error conditions.

This method checks for:

• WebTransport Closed(0, _) — web-transport-quinn v0.11+ typically converts HTTP/3-encoded ApplicationClosed codes into WebTransportError::Closed(code, reason) during SessionError conversion when decoding via error_from_http3 succeeds
• Raw QUIC ApplicationClosed with code 0
• The local side closing the connection (LocallyClosed)

Implementation Notes

We pattern match on web_transport_quinn::SessionError variants. In v0.11+, WebTransport graceful closes arrive as WebTransportError::Closed(0, _) because the crate decodes HTTP/3 error codes at the SessionError level. For raw QUIC connections, the close code is checked directly on ConnectionError::ApplicationClosed.

Coupling note: This implementation is coupled to web-transport-quinn and quinn. When transitioning to a different WebTransport backend (e.g., tokio-quiche), ensure the replacement provides equivalent error introspection, or update this method to handle the new error types.

Trait Implementations

impl Clone for SessionError

fn clone(&self) -> SessionError

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for SessionError

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

Formats the value using the given formatter.

impl Display for SessionError

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

Formats the value using the given formatter.

impl Error for SessionError

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<BoundsExceeded> for SessionError

fn from(source: BoundsExceeded) -> Self

Converts to this type from the input type.

impl From<DecodeError> for SessionError

fn from(source: DecodeError) -> Self

Converts to this type from the input type.

impl From<EncodeError> for SessionError

fn from(source: EncodeError) -> Self

Converts to this type from the input type.

impl From<Error> for SessionError

fn from(source: Error) -> Self

Converts to this type from the input type.

impl From<ServeError> for SessionError

fn from(source: ServeError) -> Self

Converts to this type from the input type.

impl From<SessionError> for ServeError

fn from(err: SessionError) -> Self

Converts to this type from the input type.