fix(server): convert panic to error if Connection::without_shutdown called on HTTP/2 conn

Author: seanmonstar

src/error.rs

@@ -128,6 +128,10 @@ pub(super) enum User {
     #[cfg(feature = "http1")]
     ManualUpgrade,
 
+    /// User called `server::Connection::without_shutdown()` on an HTTP/2 conn.
+    #[cfg(feature = "server")]
+    WithoutShutdownNonHttp1,
+
     /// User aborted in an FFI callback.
     #[cfg(feature = "ffi")]
     AbortedByCallback,
@@ -355,6 +359,11 @@ impl Error {
         Error::new_user(User::Body).with(cause)
     }
 
+    #[cfg(feature = "server")]
+    pub(super) fn new_without_shutdown_not_h1() -> Error {
+        Error::new(Kind::User(User::WithoutShutdownNonHttp1))
+    }
+
     #[cfg(feature = "http1")]
     pub(super) fn new_shutdown(cause: std::io::Error) -> Error {
         Error::new(Kind::Shutdown).with(cause)
@@ -449,6 +458,10 @@ impl Error {
             Kind::User(User::NoUpgrade) => "no upgrade available",
             #[cfg(feature = "http1")]
             Kind::User(User::ManualUpgrade) => "upgrade expected but low level API in use",
+            #[cfg(feature = "server")]
+            Kind::User(User::WithoutShutdownNonHttp1) => {
+                "without_shutdown() called on a non-HTTP/1 connection"
+            }
             #[cfg(feature = "ffi")]
             Kind::User(User::AbortedByCallback) => "operation aborted by an application callback",
         }

src/server/conn.rs

@@ -741,10 +741,6 @@ where
     /// upgrade. Once the upgrade is completed, the connection would be "done",
     /// but it is not desired to actually shutdown the IO object. Instead you
     /// would take it back using `into_parts`.
-    ///
-    /// Use [`poll_fn`](https://docs.rs/futures/0.1.25/futures/future/fn.poll_fn.html)
-    /// and [`try_ready!`](https://docs.rs/futures/0.1.25/futures/macro.try_ready.html)
-    /// to work with this function; or use the `without_shutdown` wrapper.
     pub fn poll_without_shutdown(&mut self, cx: &mut task::Context<'_>) -> Poll<crate::Result<()>>
     where
         S: Unpin,
@@ -782,6 +778,10 @@ where
 
     /// Prevent shutdown of the underlying IO object at the end of service the request,
     /// instead run `into_parts`. This is a convenience wrapper over `poll_without_shutdown`.
+    ///
+    /// # Error
+    ///
+    /// This errors if the underlying connection protocol is not HTTP/1.
     pub fn without_shutdown(self) -> impl Future<Output = crate::Result<Parts<I, S>>>
     where
         S: Unpin,
@@ -791,7 +791,7 @@ where
         let mut conn = Some(self);
         futures_util::future::poll_fn(move |cx| {
             ready!(conn.as_mut().unwrap().poll_without_shutdown(cx))?;
-            Poll::Ready(Ok(conn.take().unwrap().into_parts()))
+            Poll::Ready(conn.take().unwrap().try_into_parts().ok_or_else(crate::Error::new_without_shutdown_not_h1))
         })
     }