fix(client): exit with non-zero on error

When a connection closes with an error, surface the error to the user and exit
with non-zero.

neqo-bin/src/client/http09.rs

@@ -20,8 +20,8 @@ use std::{
 use neqo_common::{event::Provider, qdebug, qinfo, qwarn, Datagram};
 use neqo_crypto::{AuthenticationStatus, ResumptionToken};
 use neqo_transport::{
-    Connection, ConnectionEvent, EmptyConnectionIdGenerator, Error, Output, State, StreamId,
-    StreamType,
+    Connection, ConnectionError, ConnectionEvent, EmptyConnectionIdGenerator, Error, Output, State,
+    StreamId, StreamType,
 };
 use url::Url;
 
@@ -149,8 +149,11 @@ impl super::Client for Connection {
         self.close(now, app_error, msg);
     }
 
-    fn is_closed(&self) -> bool {
-        matches!(self.state(), State::Closed(..))
+    fn is_closed(&self) -> Option<ConnectionError> {
+        if let State::Closed(err) = self.state() {
+            return Some(err.clone());
+        }
+        None
     }
 
     fn stats(&self) -> neqo_transport::Stats {

neqo-bin/src/client/http3.rs

@@ -22,7 +22,8 @@ use neqo_common::{event::Provider, hex, qdebug, qinfo, qwarn, Datagram, Header};
 use neqo_crypto::{AuthenticationStatus, ResumptionToken};
 use neqo_http3::{Error, Http3Client, Http3ClientEvent, Http3Parameters, Http3State, Priority};
 use neqo_transport::{
-    AppError, Connection, EmptyConnectionIdGenerator, Error as TransportError, Output, StreamId,
+    AppError, Connection, ConnectionError, EmptyConnectionIdGenerator, Error as TransportError,
+    Output, StreamId,
 };
 use url::Url;
 
@@ -111,8 +112,11 @@ pub(crate) fn create_client(
 }
 
 impl super::Client for Http3Client {
-    fn is_closed(&self) -> bool {
-        matches!(self.state(), Http3State::Closed(..))
+    fn is_closed(&self) -> Option<ConnectionError> {
+        if let Http3State::Closed(err) = self.state() {
+            return Some(err);
+        }
+        None
     }
 
     fn process(&mut self, dgram: Option<&Datagram>, now: Instant) -> Output {

neqo-bin/src/client/mod.rs

@@ -27,7 +27,7 @@ use neqo_crypto::{
     init, Cipher, ResumptionToken,
 };
 use neqo_http3::Output;
-use neqo_transport::{AppError, ConnectionId, Error as TransportError, Version};
+use neqo_transport::{AppError, ConnectionError, ConnectionId, Error as TransportError, Version};
 use qlog::{events::EventImportance, streamer::QlogStreamer};
 use tokio::time::Sleep;
 use url::{Origin, Url};
@@ -46,6 +46,7 @@ pub enum Error {
     IoError(io::Error),
     QlogError,
     TransportError(neqo_transport::Error),
+    ApplicationError(neqo_transport::AppError),
     CryptoError(neqo_crypto::Error),
 }
 
@@ -79,6 +80,15 @@ impl From<neqo_transport::Error> for Error {
     }
 }
 
+impl From<neqo_transport::ConnectionError> for Error {
+    fn from(err: neqo_transport::ConnectionError) -> Self {
+        match err {
+            ConnectionError::Transport(e) => Self::TransportError(e),
+            ConnectionError::Application(e) => Self::ApplicationError(e),
+        }
+    }
+}
+
 impl Display for Error {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         write!(f, "Error: {self:?}")?;
@@ -371,7 +381,11 @@ trait Client {
     fn close<S>(&mut self, now: Instant, app_error: AppError, msg: S)
     where
         S: AsRef<str> + Display;
-    fn is_closed(&self) -> bool;
+    /// Returns [`Some(_)`] if the connection is closed.
+    ///
+    /// Note that connection was closed without error on
+    /// [`Some(ConnectionError::Transport(TransportError::NoError))`].
+    fn is_closed(&self) -> Option<ConnectionError>;
     fn stats(&self) -> neqo_transport::Stats;
 }
 
@@ -406,11 +420,16 @@ impl<'a, H: Handler> Runner<'a, H> {
 
             self.process(None).await?;
 
-            if self.client.is_closed() {
+            if let Some(reason) = self.client.is_closed() {
                 if self.args.stats {
                     qinfo!("{:?}", self.client.stats());
                 }
-                return Ok(self.handler.take_token());
+                return match reason {
+                    ConnectionError::Transport(TransportError::NoError) => {
+                        Ok(self.handler.take_token())
+                    }
+                    _ => Err(reason.into()),
+                };
             }
 
             match ready(self.socket, self.timeout.as_mut()).await? {

neqo-transport/src/lib.rs

@@ -70,8 +70,8 @@ const ERROR_AEAD_LIMIT_REACHED: TransportError = 15;
 #[derive(Clone, Debug, PartialEq, PartialOrd, Ord, Eq)]
 pub enum Error {
     NoError,
-    // Each time tihe error is return a different parameter is supply.
-    // This will be use to distinguish each occurance of this error.
+    // Each time this error is returned a different parameter is supplied.
+    // This will be used to distinguish each occurance of this error.
     InternalError,
     ConnectionRefused,
     FlowControlError,