fix(http1): fix intermitent panic parsing partial headers (#3812)

Closes #3811

src/proto/h1/io.rs

@@ -248,7 +248,11 @@ where
                         }
                     }
                     if curr_len > 0 {
+                        trace!("partial headers; {} bytes so far", curr_len);
                         self.partial_len = Some(curr_len);
+                    } else {
+                        // 1xx gobled some bytes
+                        self.partial_len = None;
                     }
                 }
             }

tests/client.rs

@@ -2908,6 +2908,146 @@ mod conn {
         assert_eq!(vec, b"bar=foo");
     }
 
+    #[tokio::test]
+    async fn client_100_then_http09() {
+        let (server, addr) = setup_std_test_server();
+
+        thread::spawn(move || {
+            let mut sock = server.accept().unwrap().0;
+            sock.set_read_timeout(Some(Duration::from_secs(5))).unwrap();
+            sock.set_write_timeout(Some(Duration::from_secs(5)))
+                .unwrap();
+            let mut buf = [0; 4096];
+            sock.read(&mut buf).expect("read 1");
+            sock.write_all(
+                b"\
+                HTTP/1.1 100 Continue\r\n\
+                Content-Type: text/plain\r\n\
+                Server: BaseHTTP/0.6 Python/3.12.5\r\n\
+                Date: Mon, 16 Dec 2024 03:08:27 GMT\r\n\
+            ",
+            )
+            .unwrap();
+            // That it's separate writes is important to this test
+            thread::sleep(Duration::from_millis(50));
+            sock.write_all(
+                b"\
+                \r\n\
+            ",
+            )
+            .expect("write 2");
+            thread::sleep(Duration::from_millis(50));
+            sock.write_all(
+                b"\
+                This is a sample text/plain document, without final headers.\
+                \n\n\
+            ",
+            )
+            .expect("write 3");
+        });
+
+        let tcp = tcp_connect(&addr).await.unwrap();
+
+        let (mut client, conn) = conn::http1::Builder::new()
+            .http09_responses(true)
+            .handshake(tcp)
+            .await
+            .unwrap();
+
+        tokio::spawn(async move {
+            let _ = conn.await;
+        });
+
+        let req = Request::builder()
+            .uri("/a")
+            .body(Empty::<Bytes>::new())
+            .unwrap();
+        let _res = client.send_request(req).await.expect("send_request");
+    }
+
+    #[tokio::test]
+    async fn test_try_send_request() {
+        use std::future::Future;
+        let (done_tx, done_rx) = tokio::sync::oneshot::channel::<()>();
+        let (io_srv, io_cli) = tokio_test::io::Builder::new()
+            .write(b"GET / HTTP/1.1\r\n\r\n")
+            .read(b"HTTP/1.1 200 OK\r\ncontent-length: 0\r\n\r\n")
+            .build_with_handle();
+
+        tokio::spawn(async move {
+            let _io = io_cli;
+            let _ = done_rx.await;
+        });
+
+        // make polling fair by putting both in spawns
+        tokio::spawn(async move {
+            let io = TokioIo::new(io_srv);
+            let (mut client, mut conn) = conn::http1::Builder::new()
+                .handshake::<_, Empty<Bytes>>(io)
+                .await
+                .expect("http handshake");
+
+            // get the conn ready
+            assert!(
+                future::poll_fn(|cx| Poll::Ready(Pin::new(&mut conn).poll(cx)))
+                    .await
+                    .is_pending()
+            );
+            assert!(client.is_ready());
+
+            // use the connection once
+            let mut fut1 = std::pin::pin!(client.send_request(http::Request::new(Empty::new())));
+            let _res1 = future::poll_fn(|cx| loop {
+                if let Poll::Ready(res) = fut1.as_mut().poll(cx) {
+                    return Poll::Ready(res);
+                }
+                return match Pin::new(&mut conn).poll(cx) {
+                    Poll::Ready(_) => panic!("ruh roh"),
+                    Poll::Pending => Poll::Pending,
+                };
+            })
+            .await
+            .expect("resp 1");
+
+            assert!(client.is_ready());
+
+            // simulate the server dropping the conn
+            let _ = done_tx.send(());
+            // let the server task die
+            tokio::task::yield_now().await;
+
+            let mut fut2 =
+                std::pin::pin!(client.try_send_request(http::Request::new(Empty::new())));
+            let poll1 = future::poll_fn(|cx| Poll::Ready(fut2.as_mut().poll(cx))).await;
+            assert!(poll1.is_pending(), "not already known to error");
+
+            let mut conn_opt = Some(conn);
+            // wasn't a known error, req is in queue, and now the next poll, the
+            // conn will be noticed as errored
+            let mut err = future::poll_fn(|cx| {
+                loop {
+                    if let Poll::Ready(res) = fut2.as_mut().poll(cx) {
+                        return Poll::Ready(res);
+                    }
+                    if let Some(ref mut conn) = conn_opt {
+                        match Pin::new(conn).poll(cx) {
+                            Poll::Ready(_) => {
+                                conn_opt = None;
+                            } // ok
+                            Poll::Pending => return Poll::Pending,
+                        };
+                    }
+                }
+            })
+            .await
+            .expect_err("resp 2");
+
+            assert!(err.take_message().is_some(), "request was returned");
+        })
+        .await
+        .unwrap();
+    }
+
     #[tokio::test]
     async fn http2_detect_conn_eof() {
         use futures_util::future;