feat(request-response): don't close connection on stream errors

Related: #3591.

Pull-Request: #3913.

Cargo.lock

@@ -1603,6 +1603,7 @@ dependencies = [
  "futures",
  "libp2p",
  "multiaddr",
+ "void",
 ]
 
 [[package]]
@@ -2978,8 +2979,10 @@ dependencies = [
  "libp2p-swarm-test",
  "libp2p-tcp",
  "libp2p-yamux",
+ "log",
  "rand 0.8.5",
  "smallvec",
+ "void",
 ]
 
 [[package]]

examples/file-sharing/Cargo.toml

@@ -14,3 +14,4 @@ env_logger = "0.10"
 futures = "0.3.28"
 libp2p = { path = "../../libp2p", features = ["async-std", "dns", "kad", "noise", "macros", "request-response", "tcp", "websocket", "yamux"] }
 multiaddr = { version = "0.17.1" }
+void = "1.0.2"

examples/file-sharing/src/network.rs

@@ -16,7 +16,7 @@ use libp2p::{
     multiaddr::Protocol,
     noise,
     request_response::{self, ProtocolSupport, RequestId, ResponseChannel},
-    swarm::{NetworkBehaviour, StreamUpgradeError, Swarm, SwarmBuilder, SwarmEvent},
+    swarm::{NetworkBehaviour, Swarm, SwarmBuilder, SwarmEvent},
     tcp, yamux, PeerId, Transport,
 };
 
@@ -216,7 +216,7 @@ impl EventLoop {
 
     async fn handle_event(
         &mut self,
-        event: SwarmEvent<ComposedEvent, Either<StreamUpgradeError<io::Error>, io::Error>>,
+        event: SwarmEvent<ComposedEvent, Either<void::Void, io::Error>>,
     ) {
         match event {
             SwarmEvent::Behaviour(ComposedEvent::Kademlia(

protocols/request-response/CHANGELOG.md

@@ -8,9 +8,14 @@
   These variants are no longer constructed.
   See [PR 3605].
 
+- Don't close connections if individual streams fail. 
+  Log the error instead.
+  See [PR 3913].
+
 [PR 3605]: https://github.com/libp2p/rust-libp2p/pull/3605
 [PR 3715]: https://github.com/libp2p/rust-libp2p/pull/3715
 [PR 3702]: https://github.com/libp2p/rust-libp2p/pull/3702
+[PR 3913]: https://github.com/libp2p/rust-libp2p/pull/3913
 
 ## 0.24.1
 

protocols/request-response/Cargo.toml

@@ -19,6 +19,8 @@ libp2p-swarm = { workspace = true }
 libp2p-identity = { workspace = true }
 rand = "0.8"
 smallvec = "1.6.1"
+void = "1.0.2"
+log = "0.4.17"
 
 [dev-dependencies]
 async-std = { version = "1.6.2", features = ["attributes"] }

protocols/request-response/src/handler.rs

@@ -39,7 +39,7 @@ use libp2p_swarm::{
 use smallvec::SmallVec;
 use std::{
     collections::VecDeque,
-    fmt, io,
+    fmt,
     sync::{
         atomic::{AtomicU64, Ordering},
         Arc,
@@ -65,8 +65,6 @@ where
     substream_timeout: Duration,
     /// The current connection keep-alive.
     keep_alive: KeepAlive,
-    /// A pending fatal error that results in the connection being closed.
-    pending_error: Option<StreamUpgradeError<io::Error>>,
     /// Queue of events to emit in `poll()`.
     pending_events: VecDeque<Event<TCodec>>,
     /// Outbound upgrades waiting to be emitted as an `OutboundSubstreamRequest`.
@@ -107,7 +105,6 @@ where
             outbound: VecDeque::new(),
             inbound: FuturesUnordered::new(),
             pending_events: VecDeque::new(),
-            pending_error: None,
             inbound_request_id,
         }
     }
@@ -151,21 +148,22 @@ where
                 self.pending_events
                     .push_back(Event::OutboundUnsupportedProtocols(info));
             }
-            _ => {
+            StreamUpgradeError::Apply(e) => {
-                // Anything else is considered a fatal error or misbehaviour of
+                log::debug!("outbound stream {info} failed: {e}");
-                // the remote peer and results in closing the connection.
+            }
-                self.pending_error = Some(error);
+            StreamUpgradeError::Io(e) => {
+                log::debug!("outbound stream {info} failed: {e}");
             }
         }
     }
     fn on_listen_upgrade_error(
         &mut self,
-        ListenUpgradeError { error, .. }: ListenUpgradeError<
+        ListenUpgradeError { error, info }: ListenUpgradeError<
             <Self as ConnectionHandler>::InboundOpenInfo,
             <Self as ConnectionHandler>::InboundProtocol,
         >,
     ) {
-        self.pending_error = Some(StreamUpgradeError::Apply(error));
+        log::debug!("inbound stream {info} failed: {error}");
     }
 }
 
@@ -241,7 +239,7 @@ where
 {
     type FromBehaviour = RequestProtocol<TCodec>;
     type ToBehaviour = Event<TCodec>;
-    type Error = StreamUpgradeError<io::Error>;
+    type Error = void::Void;
     type InboundProtocol = ResponseProtocol<TCodec>;
     type OutboundProtocol = RequestProtocol<TCodec>;
     type OutboundOpenInfo = RequestId;
@@ -296,12 +294,6 @@ where
     ) -> Poll<
         ConnectionHandlerEvent<RequestProtocol<TCodec>, RequestId, Self::ToBehaviour, Self::Error>,
     > {
-        // Check for a pending (fatal) error.
-        if let Some(err) = self.pending_error.take() {
-            // The handler will not be polled again by the `Swarm`.
-            return Poll::Ready(ConnectionHandlerEvent::Close(err));
-        }
-
         // Drain pending events.
         if let Some(event) = self.pending_events.pop_front() {
             return Poll::Ready(ConnectionHandlerEvent::Custom(event));