Not sending ALPN when using socks5 proxy

[cxw620]

I met with a weird issue. When using socks5 proxy, reqwest will use HTTP/1.1 during request, though HTTP/2 when using http/https proxy. Through Charles and verbose log I found that no ALPN were sent when using socks5 proxy.

I checked source code and noticed such codes:

reqwest/src/connect.rs

Lines 148 to 150 in ddf7f24

	let mut tls_proxy = tls.clone();
	tls_proxy.alpn_protocols.clear();
	(Arc::new(tls), Arc::new(tls_proxy))

reqwest/src/connect.rs

Lines 205 to 225 in ddf7f24

	#[cfg(feature = "__rustls")]
	Inner::RustlsTls { tls_proxy, .. } => {
	if dst.scheme() == Some(&Scheme::HTTPS) {
	use std::convert::TryFrom;
	use tokio_rustls::TlsConnector as RustlsConnector;
	let tls = tls_proxy.clone();
	let host = dst.host().ok_or("no host in url")?.to_string();
	let conn = socks::connect(proxy, dst, dns).await?;
	let server_name = rustls::ServerName::try_from(host.as_str())
	.map_err(|_| "Invalid Server Name")?;
	let io = RustlsConnector::from(tls)
	.connect(server_name, conn)
	.await?;
	return Ok(Conn {
	inner: self.verbose.wrap(RustlsTlsConn { inner: io }),
	is_proxy: false,
	tls_info: false,
	});
	}
	}

I think here should clone tls instead of tls_proxy since tls_proxy.alpn_protocols.clear() introduced in #466 fixing #459.

I simply verified my thoughts with testing, but I'm still uncertain, so I submit this issue.

[abacabadabacaba]

I encountered the same issue. Looking at the code, it looks like a bug.

This "feature" was introduced by #466. It seems that before it, it tried to use ALPN, but not properly activating h2 backend for some reason.