Function resolve 

pub fn resolve(config: &ProxyConfig, url: &Url) -> Result<Vec<ProxyStep>, Error>

Available on crate feature resolve only.

Routing decisions, behind the resolve feature (on by default). Decide how to reach url under config.

Never empty, and decided in this order. Pac/WPAD → Error::PacNotSupported, hostless URLs included: under an auto-config mode this entry point can answer no URL at all, so singling out mailto: for Direct while erroring on every other URL would be the stranger contract. resolve_with_pac and WinHttpPacResolver::resolve_config do take hostless first — they can answer the rest. Then, under a manual mode, hostless or bypass → Direct; else entry_for / websocket_entry for ws/wss.

The list transcribes what the configuration says; it never invents alternatives. A single manual entry yields a single step, and a versionless socks host is one step at this crate’s assumed version rather than one step per version a caller might try.

The transcription is only ever as strong as the source that produced the mode, and one source is weaker than it looks: a ProxyMode::Direct carrying ProxyConfigSource::Portal says the portal had no proxy for a fixed probe host, not for url — that variant’s doc has the reason. Nothing here can narrow the gap, because the snapshot no longer knows what was asked.

Errors

Error::PacNotSupported for auto-config modes, and Error::ProxyEntryUnusable where the only entry that would have covered url was dropped — reporting that is not the same as answering Direct.

let mode = parse::windows_manual("http=proxy.corp:8080", "<local>;*.corp.example");
let config = ProxyConfig::from_source(ProxyConfigSource::Registry, mode);

let steps = resolve(&config, &Url::parse("http://example.net/x").unwrap())?;
assert_eq!(steps[0].endpoint().unwrap().authority(), "proxy.corp:8080");

let steps = resolve(&config, &Url::parse("http://api.corp.example/x").unwrap())?;
assert_eq!(steps, vec![ProxyStep::Direct]);