Setting HTTP version is overridden by ALPN

[nihaals]

MWE

[dependencies]
reqwest = { version = "0.11.23", default-features = false, features = ["rustls-tls"] }
tokio = { version = "1.35.1", features = ["full"] }

#[tokio::main]
async fn main() {
    let client = reqwest::Client::new();
    let version = client.get("https://www.google.com/")
        .version(reqwest::Version::HTTP_11)
        .send()
        .await
        .unwrap()
        .version();
    println!("{:?}", version);
}

This gives HTTP/2.0 and when enabling rustls tracing you can see that it is setting the protocol to HTTP/2 based on ALPN.

[cxw620]

I check source code.

rustls will send ClientHello with both protocols h2 & http/1.1 by default (It seems that if you don't set http_version_pref when building reqwest client) and server side replies with ServerHelloPayload with only protocols h2, which will be saved to CommonState.

then let's see here RustlsTlsConn:

reqwest/src/connect.rs

Lines 861 to 869 in e639bdc

	impl<T: Connection + AsyncRead + AsyncWrite + Unpin> Connection for RustlsTlsConn<T> {
	fn connected(&self) -> Connected {
	if self.inner.get_ref().1.alpn_protocol() == Some(b"h2") {
	self.inner.get_ref().0.connected().negotiated_h2()
	} else {
	self.inner.get_ref().0.connected()
	}
	}
	}

You can see it read CommonState for alpn, and certainly you will fail to .version(reqwest::Version::HTTP_11).

I also check native-tls backend with the following MWE, this issue stills.

[dependencies]
reqwest = { version = "0.11.24", features = ["rustls", "native-tls-alpn", "socks"] }
tokio = { version = "1.36.0", features = ["full"] }

[patch.crates-io]
# patch to fix #2118 
reqwest = { git = 'https://github.com/cxw620/lib_reqwest.git', rev = '8a8f839483a00e7d855cac35f5d49cd7df4e8abd' }

#[tokio::main]
async fn main() {
    let client = reqwest::Client::builder()
        .use_native_tls()
        // .use_rustls_tls()
        // .proxy(reqwest::Proxy::all("socks5://127.0.0.1:20023").unwrap())
        // .danger_accept_invalid_certs(true)
        .build()
        .unwrap();
    let version = client
        .get("https://www.google.com/")
        .version(reqwest::Version::HTTP_11)
        .send()
        .await
        .unwrap()
        .version();
    println!("{:?}", version); // get HTTP/2.0 instead of HTTP/1.1
}

This issue will be hard to resolve.

P.S.:
Through testing, I even found a new problem in branch hyper-v1 that it seems that when using native-tls backend reqwest will not perform alpn negotiation, and socks5 proxy doesn't work with error hyper::Error(Parse(Version)) (when use Charles), while rustls backend works well...