Enum DialError 

pub enum DialError {
    InvalidAddress(String),
    LocalSocket(String),
    TlsConfig(String),
    Transport(TransportError),
}

Why a QUIC dial did not produce a connection.

Separate from TransportError so the failures that happen before any packet is sent — a bad address, a socket this machine would not open, a TLS config it rejects — stay distinguishable from a peer that would not talk to us. DialError::phase is that distinction as a value.

Why there is a variant for a socket that would not open

A bind this machine refused is this side’s failure, and the type is what has to say so. Folding it into InvalidAddress leaves the message as the only thing telling the two apart — a substring test wearing a type’s clothes. A consumer reading it that way recovers “this machine has no IPv6 stack” only where the prose happens to contain could not bind, and files the result at whichever phase the caller named, which for a single call to dial_quic_to is one word for four stages: a failed v6 bind then publishes as a relay that failed a QUIC handshake, on a dial where no packet left the machine.

The WebTransport arm offers no such substring to find. wtransport’s endpoint constructor binds the socket too and its failure carries no could not bind in the message, so a TransportError there reaches ErrorCause::Transport through a draft’s ConnectionError, and is_local answers false for it — a socket this machine could not open, filed against the peer. Both arms raise this variant.

Why it goes no further than this type

The fourteen From<DialError> for ConnectionError impls map this variant onto ConnectionError::InvalidAddress, which is one of the variants the facade reads as ErrorCause::Facade, and with it is_local() == true — the right answer for a failure this side decided. Splitting it further there would add public variants for a distinction no caller on that path reads: a draft Connection is built by a caller who named a host:port, not by one measuring which stage of a dial died. The reader of the distinction is a caller of dial_quic_to, and it reads it off this type directly.

Variants

InvalidAddress(String)

addr is not a host:port this machine can resolve to a socket address.

LocalSocket(String)

A local socket could not be opened to send from.

Nothing about the target: the address is fine and this machine would not give us a socket to reach it with. The common cause by a distance is dialling a v6 address from a host or container with no IPv6 stack, which is a routine outcome for anything that enumerates both families of a dual-stack name — and a fact about the dialler, never about the peer.

TlsConfig(String)

The TLS client configuration could not be built.

Transport(TransportError)

The dial itself failed.

Implementations

impl DialError

pub fn phase(&self) -> DialPhase

Which stage of the dial this failure came from.

Total and structural: every variant answers, and no arm reads a message. DialError::Transport splits on whether the transport error is the typed TransportError::Handshake — which by construction exists only where a peer answered — so everything else under it is the stack declining to start, which is DialPhase::Connect.

pub fn is_local(&self) -> bool

Whether the dial failed before a packet left this machine.

True for everything but DialPhase::Handshake. The name matches AnyConnectionError::is_local, which answers the same question for everything after the dial, and it is worth being exact about what each half of the answer buys:

• true is a guarantee. Nothing was sent, so the failure cannot be evidence about the peer, and anything that publishes it as such is publishing a finding that never happened.
• false is not the opposite guarantee. It says the machine got as far as sending, and a handshake can still fail for reasons that are nobody’s fault in particular — a timeout, a network that dropped the packets. Read TransportError::Handshake’s codes for what the peer actually said; this only says whether there was a peer to ask.

Trait Implementations

impl Debug for DialError

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

Formats the value using the given formatter.

impl Display for DialError

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

Formats the value using the given formatter.

impl Error for DialError

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<DialError> for ConnectionError

fn from(e: DialError) -> Self

Maps a dial failure onto the variants this error already carries, so InvalidAddress, TlsConfig and Transport are what a caller has to match on.

LocalSocket joins InvalidAddress, and that is the answer being kept

A socket this machine would not open has a variant of its own on DialError, and it still arrives here. Not laziness about the churn — InvalidAddress is one of the variants the facade reads as ErrorCause::Facade, which is_local answers true for, and a failed bind is this side’s by definition. Routing it to Transport would read better in prose and would publish this machine’s missing IPv6 stack as the relay’s doing.

The phase is not lost, only unread on this path. A caller measuring which stage of a dial died reads DialError::phase off the dial itself; a caller who arrived at this type named a host:port and asked for a connection, not for a measurement, and a public variant here for a distinction nothing on this path reads is churn with no reader, which is why this impl stays flat.

impl From<DialError> for ConnectionError

fn from(e: DialError) -> Self

Maps a dial failure onto the variants this error already has, so a caller matches InvalidAddress or TlsConfig.

LocalSocket joins InvalidAddress, and that is the answer being kept

A socket this machine would not open has a variant of its own on DialError, and it still arrives here. Not laziness about the churn — InvalidAddress is one of the variants the facade reads as ErrorCause::Facade, which is_local answers true for, and a failed bind is this side’s by definition. Routing it to Transport would read better in prose and would publish this machine’s missing IPv6 stack as the relay’s doing.

The phase is not lost, only unread on this path. A caller measuring which stage of a dial died reads DialError::phase off the dial itself; a caller who arrived at this type named a host:port and asked for a connection, not for a measurement, and a public variant here for a distinction nothing on this path reads is churn with no reader, which is why this impl stays flat.

impl From<DialError> for ConnectionError

fn from(e: DialError) -> Self

Maps a dial failure onto the variants this error already has, so a caller matches InvalidAddress or TlsConfig.

LocalSocket joins InvalidAddress, and that is the answer being kept

A socket this machine would not open has a variant of its own on DialError, and it still arrives here. Not laziness about the churn — InvalidAddress is one of the variants the facade reads as ErrorCause::Facade, which is_local answers true for, and a failed bind is this side’s by definition. Routing it to Transport would read better in prose and would publish this machine’s missing IPv6 stack as the relay’s doing.

The phase is not lost, only unread on this path. A caller measuring which stage of a dial died reads DialError::phase off the dial itself; a caller who arrived at this type named a host:port and asked for a connection, not for a measurement, and a public variant here for a distinction nothing on this path reads is churn with no reader, which is why this impl stays flat.

impl From<DialError> for ConnectionError

fn from(e: DialError) -> Self

Maps a dial failure onto the variants this error already has, so a caller matches InvalidAddress or TlsConfig.

LocalSocket joins InvalidAddress, and that is the answer being kept

A socket this machine would not open has a variant of its own on DialError, and it still arrives here. Not laziness about the churn — InvalidAddress is one of the variants the facade reads as ErrorCause::Facade, which is_local answers true for, and a failed bind is this side’s by definition. Routing it to Transport would read better in prose and would publish this machine’s missing IPv6 stack as the relay’s doing.

The phase is not lost, only unread on this path. A caller measuring which stage of a dial died reads DialError::phase off the dial itself; a caller who arrived at this type named a host:port and asked for a connection, not for a measurement, and a public variant here for a distinction nothing on this path reads is churn with no reader, which is why this impl stays flat.

impl From<DialError> for ConnectionError

fn from(e: DialError) -> Self

Maps a dial failure onto the variants this error already has, so a caller matches InvalidAddress or TlsConfig.

LocalSocket joins InvalidAddress, and that is the answer being kept

A socket this machine would not open has a variant of its own on DialError, and it still arrives here. Not laziness about the churn — InvalidAddress is one of the variants the facade reads as ErrorCause::Facade, which is_local answers true for, and a failed bind is this side’s by definition. Routing it to Transport would read better in prose and would publish this machine’s missing IPv6 stack as the relay’s doing.

The phase is not lost, only unread on this path. A caller measuring which stage of a dial died reads DialError::phase off the dial itself; a caller who arrived at this type named a host:port and asked for a connection, not for a measurement, and a public variant here for a distinction nothing on this path reads is churn with no reader, which is why this impl stays flat.

impl From<DialError> for ConnectionError

fn from(e: DialError) -> Self

Maps a dial failure onto the variants this error already has, so a caller matches InvalidAddress or TlsConfig.

LocalSocket joins InvalidAddress, and that is the answer being kept

A socket this machine would not open has a variant of its own on DialError, and it still arrives here. Not laziness about the churn — InvalidAddress is one of the variants the facade reads as ErrorCause::Facade, which is_local answers true for, and a failed bind is this side’s by definition. Routing it to Transport would read better in prose and would publish this machine’s missing IPv6 stack as the relay’s doing.

The phase is not lost, only unread on this path. A caller measuring which stage of a dial died reads DialError::phase off the dial itself; a caller who arrived at this type named a host:port and asked for a connection, not for a measurement, and a public variant here for a distinction nothing on this path reads is churn with no reader, which is why this impl stays flat.

impl From<DialError> for ConnectionError

fn from(e: DialError) -> Self

Maps a dial failure onto the variants this error already has, so a caller matches InvalidAddress or TlsConfig.

LocalSocket joins InvalidAddress, and that is the answer being kept

A socket this machine would not open has a variant of its own on DialError, and it still arrives here. Not laziness about the churn — InvalidAddress is one of the variants the facade reads as ErrorCause::Facade, which is_local answers true for, and a failed bind is this side’s by definition. Routing it to Transport would read better in prose and would publish this machine’s missing IPv6 stack as the relay’s doing.

The phase is not lost, only unread on this path. A caller measuring which stage of a dial died reads DialError::phase off the dial itself; a caller who arrived at this type named a host:port and asked for a connection, not for a measurement, and a public variant here for a distinction nothing on this path reads is churn with no reader, which is why this impl stays flat.

impl From<DialError> for ConnectionError

fn from(e: DialError) -> Self

Maps a dial failure onto the variants this error already has, so a caller matches InvalidAddress or TlsConfig.

LocalSocket joins InvalidAddress, and that is the answer being kept

A socket this machine would not open has a variant of its own on DialError, and it still arrives here. Not laziness about the churn — InvalidAddress is one of the variants the facade reads as ErrorCause::Facade, which is_local answers true for, and a failed bind is this side’s by definition. Routing it to Transport would read better in prose and would publish this machine’s missing IPv6 stack as the relay’s doing.

The phase is not lost, only unread on this path. A caller measuring which stage of a dial died reads DialError::phase off the dial itself; a caller who arrived at this type named a host:port and asked for a connection, not for a measurement, and a public variant here for a distinction nothing on this path reads is churn with no reader, which is why this impl stays flat.

impl From<DialError> for ConnectionError

fn from(e: DialError) -> Self

Maps a dial failure onto the variants this error already has, so a caller matches InvalidAddress or TlsConfig.

LocalSocket joins InvalidAddress, and that is the answer being kept

A socket this machine would not open has a variant of its own on DialError, and it still arrives here. Not laziness about the churn — InvalidAddress is one of the variants the facade reads as ErrorCause::Facade, which is_local answers true for, and a failed bind is this side’s by definition. Routing it to Transport would read better in prose and would publish this machine’s missing IPv6 stack as the relay’s doing.

The phase is not lost, only unread on this path. A caller measuring which stage of a dial died reads DialError::phase off the dial itself; a caller who arrived at this type named a host:port and asked for a connection, not for a measurement, and a public variant here for a distinction nothing on this path reads is churn with no reader, which is why this impl stays flat.

impl From<DialError> for ConnectionError

fn from(e: DialError) -> Self

Maps a dial failure onto the variants this error already has, so a caller matches InvalidAddress or TlsConfig.

LocalSocket joins InvalidAddress, and that is the answer being kept

A socket this machine would not open has a variant of its own on DialError, and it still arrives here. Not laziness about the churn — InvalidAddress is one of the variants the facade reads as ErrorCause::Facade, which is_local answers true for, and a failed bind is this side’s by definition. Routing it to Transport would read better in prose and would publish this machine’s missing IPv6 stack as the relay’s doing.

The phase is not lost, only unread on this path. A caller measuring which stage of a dial died reads DialError::phase off the dial itself; a caller who arrived at this type named a host:port and asked for a connection, not for a measurement, and a public variant here for a distinction nothing on this path reads is churn with no reader, which is why this impl stays flat.

impl From<DialError> for ConnectionError

fn from(e: DialError) -> Self

Maps a dial failure onto the variants this error already has, so a caller matches InvalidAddress or TlsConfig.

LocalSocket joins InvalidAddress, and that is the answer being kept

A socket this machine would not open has a variant of its own on DialError, and it still arrives here. Not laziness about the churn — InvalidAddress is one of the variants the facade reads as ErrorCause::Facade, which is_local answers true for, and a failed bind is this side’s by definition. Routing it to Transport would read better in prose and would publish this machine’s missing IPv6 stack as the relay’s doing.

The phase is not lost, only unread on this path. A caller measuring which stage of a dial died reads DialError::phase off the dial itself; a caller who arrived at this type named a host:port and asked for a connection, not for a measurement, and a public variant here for a distinction nothing on this path reads is churn with no reader, which is why this impl stays flat.

impl From<DialError> for ConnectionError

fn from(e: DialError) -> Self

Maps a dial failure onto the variants this error already has, so a caller matches InvalidAddress or TlsConfig.

LocalSocket joins InvalidAddress, and that is the answer being kept

A socket this machine would not open has a variant of its own on DialError, and it still arrives here. Not laziness about the churn — InvalidAddress is one of the variants the facade reads as ErrorCause::Facade, which is_local answers true for, and a failed bind is this side’s by definition. Routing it to Transport would read better in prose and would publish this machine’s missing IPv6 stack as the relay’s doing.

The phase is not lost, only unread on this path. A caller measuring which stage of a dial died reads DialError::phase off the dial itself; a caller who arrived at this type named a host:port and asked for a connection, not for a measurement, and a public variant here for a distinction nothing on this path reads is churn with no reader, which is why this impl stays flat.

impl From<DialError> for ConnectionError

fn from(e: DialError) -> Self

Maps a dial failure onto the variants this error already has, so a caller matches InvalidAddress or TlsConfig.

LocalSocket joins InvalidAddress, and that is the answer being kept

A socket this machine would not open has a variant of its own on DialError, and it still arrives here. Not laziness about the churn — InvalidAddress is one of the variants the facade reads as ErrorCause::Facade, which is_local answers true for, and a failed bind is this side’s by definition. Routing it to Transport would read better in prose and would publish this machine’s missing IPv6 stack as the relay’s doing.

The phase is not lost, only unread on this path. A caller measuring which stage of a dial died reads DialError::phase off the dial itself; a caller who arrived at this type named a host:port and asked for a connection, not for a measurement, and a public variant here for a distinction nothing on this path reads is churn with no reader, which is why this impl stays flat.

impl From<DialError> for ConnectionError

fn from(e: DialError) -> Self

Maps a dial failure onto the variants this error already has, so a caller matches InvalidAddress or TlsConfig.

LocalSocket joins InvalidAddress, and that is the answer being kept

A socket this machine would not open has a variant of its own on DialError, and it still arrives here. Not laziness about the churn — InvalidAddress is one of the variants the facade reads as ErrorCause::Facade, which is_local answers true for, and a failed bind is this side’s by definition. Routing it to Transport would read better in prose and would publish this machine’s missing IPv6 stack as the relay’s doing.

The phase is not lost, only unread on this path. A caller measuring which stage of a dial died reads DialError::phase off the dial itself; a caller who arrived at this type named a host:port and asked for a connection, not for a measurement, and a public variant here for a distinction nothing on this path reads is churn with no reader, which is why this impl stays flat.

impl From<DialError> for ConnectionError

fn from(e: DialError) -> Self

Maps a dial failure onto the variants this error already has, so a caller matches InvalidAddress or TlsConfig.

LocalSocket joins InvalidAddress, and that is the answer being kept

A socket this machine would not open has a variant of its own on DialError, and it still arrives here. Not laziness about the churn — InvalidAddress is one of the variants the facade reads as ErrorCause::Facade, which is_local answers true for, and a failed bind is this side’s by definition. Routing it to Transport would read better in prose and would publish this machine’s missing IPv6 stack as the relay’s doing.

The phase is not lost, only unread on this path. A caller measuring which stage of a dial died reads DialError::phase off the dial itself; a caller who arrived at this type named a host:port and asked for a connection, not for a measurement, and a public variant here for a distinction nothing on this path reads is churn with no reader, which is why this impl stays flat.

impl From<TransportError> for DialError

fn from(source: TransportError) -> Self

Converts to this type from the input type.