If the runtime is dropped while a DNS request is being made, it can
lead to a panic. This patch checks if the task was cancelled, and
returns a generic IO error instead of panicking in that case.
The following code reproduces the problem on my macOS machine:
```
use hyper::Client;
use tokio::runtime;
type Result<T> = std::result::Result<T, Box<dyn std::error::Error + Send + Sync>>;
fn main() {
let rt = runtime::Builder::new()
.threaded_scheduler()
.core_threads(1)
.enable_all()
.build()
.unwrap();
// spawn a request and then drop the runtime immediately
rt.spawn(fetch_url());
}
async fn fetch_url() -> Result<()> {
let url: hyper::Uri = "http://example.com".parse()?;
let client = Client::builder().build_http::<hyper::Body>();
let res = client.get(url).await?;
println!("Response: {}", res.status());
Ok(())
}
```
This is *just* a "trait alias". It is automatically implemented for all
`Service<Uri>`s that have the required bounds. It's purpose being public
is to ease setting trait bounds outside of hyper. Therefore, it doesn't
have any exposed associated types, to prevent otherwise relying on any
super-traits that hyper requires.
Instead of returning a tuple `(impl AsyncRead + AsyncWrite, Connected)`,
this adds a new trait, `hyper::client::connect::Connection`, which
allows querying the connection type for a `Connected`.
BREAKING CHANGE: Connectors no longer return a tuple of
`(T, Connected)`, but a single `T: Connection`.
It is not possible to connect to an IPv4 address from an IPv6 address or
vice-versa so don't waste time trying. If no remote addresses match then a
"missing connect error" will now occur.
Closes#1903
BREAKING CHANGE: The `Resolve` trait is gone. All custom resolves should
implement `tower::Service` instead.
The error type of `HttpConnector` has been changed away from
`std::io::Error`.
The `Connect` trait is now essentially an alias for
`Service<Destination>`, with a blanket implementation as such, and is
sealed.
Closes#1902
BREAKING CHANGE: Any manual implementations of `Connect` must instead
implement `tower::Service<Destination>`.
This takes the same strategy as golang, where the timeout value is
divided equally between the candidate socket addresses.
If happy eyeballs is enabled, the division takes place "below" the
IPv4/IPv6 partitioning.
The `HttpConnector` and `AddrListener` types which make use of
`tokio::tcp` have been made their own optional feature. This allows
using them without requiring the *full* tokio runtime.
