fix(http1): http1 server graceful shutdown fix

fix issue in the graceful shutdown logic
which causes the connection future to hang
when graceful shutdown is called prior to any
requests being  made. This fix checks to see
if the connection is still in its initial state
when disable_keep_alive is called, and starts the
shutdown process if it is.

This addresses issue hyperium#2730

src/proto/h1/conn.rs

@@ -175,6 +175,11 @@ where
         }
     }
 
+    #[cfg(feature = "server")]
+    pub(crate) fn has_initial_read_write_state(&self) -> bool {
+        matches!(self.state.reading, Reading::Init) && matches!(self.state.writing, Writing::Init)
+    }
+
     fn should_error_on_eof(&self) -> bool {
         // If we're idle, it's probably just the connection closing gracefully.
         T::should_error_on_parse_eof() && !self.state.is_idle()

src/proto/h1/dispatch.rs

@@ -28,7 +28,8 @@ pub(crate) trait Dispatch {
         self: Pin<&mut Self>,
         cx: &mut task::Context<'_>,
     ) -> Poll<Option<Result<(Self::PollItem, Self::PollBody), Self::PollError>>>;
-    fn recv_msg(&mut self, msg: crate::Result<(Self::RecvItem, IncomingBody)>) -> crate::Result<()>;
+    fn recv_msg(&mut self, msg: crate::Result<(Self::RecvItem, IncomingBody)>)
+        -> crate::Result<()>;
     fn poll_ready(&mut self, cx: &mut task::Context<'_>) -> Poll<Result<(), ()>>;
     fn should_poll(&self) -> bool;
 }
@@ -81,7 +82,11 @@ where
     #[cfg(feature = "server")]
     pub(crate) fn disable_keep_alive(&mut self) {
         self.conn.disable_keep_alive();
-        if self.conn.is_write_closed() {
+
+        // If keep alive has been disabled and no read or write has been seen on
+        // the connection yet, we must be in a state where the server is being asked to
+        // shut down before any data has been seen on the connection
+        if self.conn.is_write_closed() || self.conn.has_initial_read_write_state() {
             self.close();
         }
     }
@@ -249,7 +254,8 @@ where
                 let body = match body_len {
                     DecodedLength::ZERO => IncomingBody::empty(),
                     other => {
-                        let (tx, rx) = IncomingBody::new_channel(other, wants.contains(Wants::EXPECT));
+                        let (tx, rx) =
+                            IncomingBody::new_channel(other, wants.contains(Wants::EXPECT));
                         self.body_tx = Some(tx);
                         rx
                     }

tests/server.rs

@@ -31,6 +31,7 @@ use hyper::body::{Body, Incoming as IncomingBody};
 use hyper::server::conn::{http1, http2};
 use hyper::service::{service_fn, Service};
 use hyper::{Method, Request, Response, StatusCode, Uri, Version};
+use tokio::pin;
 
 mod support;
 
@@ -2136,6 +2137,31 @@ async fn max_buf_size() {
         .expect_err("should TooLarge error");
 }
 
+#[cfg(feature = "http1")]
+#[tokio::test]
+async fn graceful_shutdown_before_first_request_no_block() {
+    let (listener, addr) = setup_tcp_listener();
+
+    tokio::spawn(async move {
+        let socket = listener.accept().await.unwrap().0;
+
+        let future = http1::Builder::new().serve_connection(socket, HelloWorld);
+        pin!(future);
+        future.as_mut().graceful_shutdown();
+
+        future.await.unwrap();
+    });
+
+    let mut stream = TkTcpStream::connect(addr).await.unwrap();
+
+    let mut buf = vec![];
+
+    tokio::time::timeout(Duration::from_secs(5), stream.read_to_end(&mut buf))
+        .await
+        .expect("timed out waiting for graceful shutdown")
+        .expect("error receiving response");
+}
+
 #[test]
 fn streaming_body() {
     use futures_util::StreamExt;