swarm-derive/: Make event_process = false the default (#2214)

Co-authored-by: Max Inden <mail@max-inden.de>

examples/chat-tokio.rs

@@ -87,6 +87,7 @@ async fn main() -> Result<(), Box<dyn Error>> {
     // requires the implementations of `NetworkBehaviourEventProcess` for
     // the events of each behaviour.
     #[derive(NetworkBehaviour)]
+    #[behaviour(event_process = true)]
     struct MyBehaviour {
         floodsub: Floodsub,
         mdns: Mdns,

examples/chat.rs

@@ -55,7 +55,7 @@ use libp2p::{
     floodsub::{self, Floodsub, FloodsubEvent},
     identity,
     mdns::{Mdns, MdnsConfig, MdnsEvent},
-    swarm::{NetworkBehaviourEventProcess, SwarmEvent},
+    swarm::SwarmEvent,
     Multiaddr, NetworkBehaviour, PeerId, Swarm,
 };
 use std::{
@@ -83,6 +83,7 @@ async fn main() -> Result<(), Box<dyn Error>> {
     // Use the derive to generate delegating NetworkBehaviour impl and require the
     // NetworkBehaviourEventProcess implementations below.
     #[derive(NetworkBehaviour)]
+    #[behaviour(out_event = "OutEvent")]
     struct MyBehaviour {
         floodsub: Floodsub,
         mdns: Mdns,
@@ -93,36 +94,21 @@ async fn main() -> Result<(), Box<dyn Error>> {
         ignored_member: bool,
     }
 
-    impl NetworkBehaviourEventProcess<FloodsubEvent> for MyBehaviour {
+    #[derive(Debug)]
-        // Called when `floodsub` produces an event.
+    enum OutEvent {
-        fn inject_event(&mut self, message: FloodsubEvent) {
+        Floodsub(FloodsubEvent),
-            if let FloodsubEvent::Message(message) = message {
+        Mdns(MdnsEvent),
-                println!(
-                    "Received: '{:?}' from {:?}",
-                    String::from_utf8_lossy(&message.data),
-                    message.source
-                );
     }
+
+    impl From<MdnsEvent> for OutEvent {
+        fn from(v: MdnsEvent) -> Self {
+            Self::Mdns(v)
         }
     }
 
-    impl NetworkBehaviourEventProcess<MdnsEvent> for MyBehaviour {
+    impl From<FloodsubEvent> for OutEvent {
-        // Called when `mdns` produces an event.
+        fn from(v: FloodsubEvent) -> Self {
-        fn inject_event(&mut self, event: MdnsEvent) {
+            Self::Floodsub(v)
-            match event {
-                MdnsEvent::Discovered(list) => {
-                    for (peer, _) in list {
-                        self.floodsub.add_node_to_partial_view(peer);
-                    }
-                }
-                MdnsEvent::Expired(list) => {
-                    for (peer, _) in list {
-                        if !self.mdns.has_node(&peer) {
-                            self.floodsub.remove_node_from_partial_view(&peer);
-                        }
-                    }
-                }
-            }
         }
     }
 
@@ -166,11 +152,41 @@ async fn main() -> Result<(), Box<dyn Error>> {
         }
         loop {
             match swarm.poll_next_unpin(cx) {
-                Poll::Ready(Some(event)) => {
+                Poll::Ready(Some(SwarmEvent::NewListenAddr { address, .. })) => {
-                    if let SwarmEvent::NewListenAddr { address, .. } = event {
                     println!("Listening on {:?}", address);
                 }
+                Poll::Ready(Some(SwarmEvent::Behaviour(OutEvent::Floodsub(
+                    FloodsubEvent::Message(message),
+                )))) => {
+                    println!(
+                        "Received: '{:?}' from {:?}",
+                        String::from_utf8_lossy(&message.data),
+                        message.source
+                    );
                 }
+                Poll::Ready(Some(SwarmEvent::Behaviour(OutEvent::Mdns(
+                    MdnsEvent::Discovered(list),
+                )))) => {
+                    for (peer, _) in list {
+                        swarm
+                            .behaviour_mut()
+                            .floodsub
+                            .add_node_to_partial_view(peer);
+                    }
+                }
+                Poll::Ready(Some(SwarmEvent::Behaviour(OutEvent::Mdns(MdnsEvent::Expired(
+                    list,
+                ))))) => {
+                    for (peer, _) in list {
+                        if !swarm.behaviour_mut().mdns.has_node(&peer) {
+                            swarm
+                                .behaviour_mut()
+                                .floodsub
+                                .remove_node_from_partial_view(&peer);
+                        }
+                    }
+                }
+                Poll::Ready(Some(_)) => {}
                 Poll::Ready(None) => return Poll::Ready(Ok(())),
                 Poll::Pending => break,
             }

examples/distributed-key-value-store.rs

@@ -71,6 +71,7 @@ async fn main() -> Result<(), Box<dyn Error>> {
 
     // We create a custom network behaviour that combines Kademlia and mDNS.
     #[derive(NetworkBehaviour)]
+    #[behaviour(event_process = true)]
     struct MyBehaviour {
         kademlia: Kademlia<MemoryStore>,
         mdns: Mdns,

examples/file-sharing.rs

@@ -582,7 +582,7 @@ mod network {
     }
 
     #[derive(NetworkBehaviour)]
-    #[behaviour(event_process = false, out_event = "ComposedEvent")]
+    #[behaviour(out_event = "ComposedEvent")]
     struct ComposedBehaviour {
         request_response: RequestResponse<FileExchangeCodec>,
         kademlia: Kademlia<MemoryStore>,

examples/ipfs-private.rs

@@ -163,6 +163,7 @@ fn main() -> Result<(), Box<dyn Error>> {
 
     // We create a custom network behaviour that combines gossipsub, ping and identify.
     #[derive(NetworkBehaviour)]
+    #[behaviour(event_process = true)]
     struct MyBehaviour {
         gossipsub: Gossipsub,
         identify: Identify,

protocols/relay/examples/relay.rs

@@ -209,7 +209,7 @@ fn get_client_listen_address(opt: &Opt) -> String {
 }
 
 #[derive(NetworkBehaviour)]
-#[behaviour(out_event = "Event", event_process = false)]
+#[behaviour(out_event = "Event")]
 struct Behaviour {
     relay: Relay,
     ping: ping::Behaviour,

protocols/relay/tests/lib.rs

@@ -1129,7 +1129,11 @@ fn yield_incoming_connection_through_correct_listener() {
 }
 
 #[derive(NetworkBehaviour)]
-#[behaviour(out_event = "CombinedEvent", poll_method = "poll")]
+#[behaviour(
+    out_event = "CombinedEvent",
+    poll_method = "poll",
+    event_process = true
+)]
 struct CombinedBehaviour {
     relay: Relay,
     ping: ping::Behaviour,
@@ -1195,6 +1199,7 @@ impl NetworkBehaviourEventProcess<()> for CombinedBehaviour {
 }
 
 #[derive(NetworkBehaviour)]
+#[behaviour(event_process = true)]
 struct CombinedKeepAliveBehaviour {
     relay: Relay,
     keep_alive: DummyBehaviour,

swarm-derive/CHANGELOG.md

@@ -2,6 +2,8 @@
 
 - Update to latest `libp2p-swarm` changes (see [PR 2191]).
 
+- Make `event_process = false` the default.
+
 [PR 2191]: https://github.com/libp2p/rust-libp2p/pull/2191
 
 # 0.24.0 [2021-07-12]

swarm-derive/src/lib.rs

@@ -71,7 +71,7 @@ fn build_struct(ast: &DeriveInput, data_struct: &DataStruct) -> TokenStream {
 
     // Whether or not we require the `NetworkBehaviourEventProcess` trait to be implemented.
     let event_process = {
-        let mut event_process = true; // Default to true for backwards compatibility
+        let mut event_process = false;
 
         for meta_items in ast.attrs.iter().filter_map(get_meta_items) {
             for meta_item in meta_items {

swarm-derive/tests/test.rs

@@ -38,6 +38,7 @@ fn empty() {
 fn one_field() {
     #[allow(dead_code)]
     #[derive(NetworkBehaviour)]
+    #[behaviour(event_process = true)]
     struct Foo {
         ping: libp2p::ping::Ping,
     }
@@ -56,6 +57,7 @@ fn one_field() {
 fn two_fields() {
     #[allow(dead_code)]
     #[derive(NetworkBehaviour)]
+    #[behaviour(event_process = true)]
     struct Foo {
         ping: libp2p::ping::Ping,
         identify: libp2p::identify::Identify,
@@ -79,6 +81,7 @@ fn two_fields() {
 fn three_fields() {
     #[allow(dead_code)]
     #[derive(NetworkBehaviour)]
+    #[behaviour(event_process = true)]
     struct Foo {
         ping: libp2p::ping::Ping,
         identify: libp2p::identify::Identify,
@@ -109,6 +112,7 @@ fn three_fields() {
 fn three_fields_non_last_ignored() {
     #[allow(dead_code)]
     #[derive(NetworkBehaviour)]
+    #[behaviour(event_process = true)]
     struct Foo {
         ping: libp2p::ping::Ping,
         #[behaviour(ignore)]
@@ -134,7 +138,7 @@ fn three_fields_non_last_ignored() {
 fn custom_polling() {
     #[allow(dead_code)]
     #[derive(NetworkBehaviour)]
-    #[behaviour(poll_method = "foo")]
+    #[behaviour(poll_method = "foo", event_process = true)]
     struct Foo {
         ping: libp2p::ping::Ping,
         identify: libp2p::identify::Identify,
@@ -173,7 +177,7 @@ fn custom_polling() {
 fn custom_event_no_polling() {
     #[allow(dead_code)]
     #[derive(NetworkBehaviour)]
-    #[behaviour(out_event = "Vec<String>")]
+    #[behaviour(out_event = "Vec<String>", event_process = true)]
     struct Foo {
         ping: libp2p::ping::Ping,
         identify: libp2p::identify::Identify,
@@ -197,7 +201,7 @@ fn custom_event_no_polling() {
 fn custom_event_and_polling() {
     #[allow(dead_code)]
     #[derive(NetworkBehaviour)]
-    #[behaviour(poll_method = "foo", out_event = "String")]
+    #[behaviour(poll_method = "foo", out_event = "String", event_process = true)]
     struct Foo {
         ping: libp2p::ping::Ping,
         identify: libp2p::identify::Identify,
@@ -236,6 +240,7 @@ fn custom_event_and_polling() {
 fn where_clause() {
     #[allow(dead_code)]
     #[derive(NetworkBehaviour)]
+    #[behaviour(event_process = true)]
     struct Foo<T: Copy> {
         ping: libp2p::ping::Ping,
         bar: T,
@@ -248,12 +253,14 @@ fn nested_derives_with_import() {
 
     #[allow(dead_code)]
     #[derive(NetworkBehaviour)]
+    #[behaviour(event_process = true)]
     struct Foo {
         ping: libp2p::ping::Ping,
     }
 
     #[allow(dead_code)]
     #[derive(NetworkBehaviour)]
+    #[behaviour(event_process = true)]
     struct Bar {
         foo: Foo,
     }
@@ -293,7 +300,7 @@ fn event_process_false() {
 
     #[allow(dead_code)]
     #[derive(NetworkBehaviour)]
-    #[behaviour(out_event = "BehaviourOutEvent", event_process = false)]
+    #[behaviour(out_event = "BehaviourOutEvent")]
     struct Foo {
         ping: libp2p::ping::Ping,
         identify: libp2p::identify::Identify,