Enum DeclarationError 

pub enum DeclarationError {
    Unparseable {
        declared: String,
    },
    NoVersion,
}

Why a session could not be established.

Deliberately smaller than the engine’s own error: these are the cases where the protocol’s answer is “I cannot”, and the engine adds its own state errors around them. The distinction matters because only one of the two is something a peer can fix by asking for something different.

Variants

Unparseable

The peer named a version this side cannot parse.

Fields

declared: String

What the peer sent, verbatim. It is a peer’s own token, and the message is what lets an operator see the spelling that failed.

NoVersion

A message declared no version, and there is no session to fall back to.

The distinction from a missing header on a stateful session is the whole point of the stateless lifecycle: with nothing established, there is nothing to assume from, so an absent version is an error rather than a default. Answering with a guess here is how a stateless server ends up serving a modern peer a 2024 profile.

Trait Implementations

impl Clone for DeclarationError

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for DeclarationError

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

Formats the value using the given formatter.

impl Display for DeclarationError

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

Formats the value using the given formatter.

impl Eq for DeclarationError

impl Error for DeclarationError

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<DeclarationError> for EngineError

fn from(source: DeclarationError) -> Self

Converts to this type from the input type.

impl PartialEq for DeclarationError

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for DeclarationError