swarm-derive/: Remove support for ignoring fields on struct (#2842)

With the removal of `NetworkBehaviourEventProcess` there is no more need for
ignoring fields.

examples/chat.rs

@@ -85,11 +85,6 @@ async fn main() -> Result<(), Box<dyn Error>> {
     struct MyBehaviour {
         floodsub: Floodsub,
         mdns: Mdns,
-
-        // Struct fields which do not implement NetworkBehaviour need to be ignored
-        #[behaviour(ignore)]
-        #[allow(dead_code)]
-        ignored_member: bool,
     }
 
     #[allow(clippy::large_enum_variant)]
@@ -117,7 +112,6 @@ async fn main() -> Result<(), Box<dyn Error>> {
         let mut behaviour = MyBehaviour {
             floodsub: Floodsub::new(local_peer_id),
             mdns,
-            ignored_member: false,
         };
 
         behaviour.floodsub.subscribe(floodsub_topic.clone());

swarm-derive/CHANGELOG.md

@@ -8,6 +8,11 @@
 [PR 2840]: https://github.com/libp2p/rust-libp2p/pull/2840
 [PR 2841]: https://github.com/libp2p/rust-libp2p/pull/2841
 
+- Remove support for non-`NetworkBehaviour` fields on main `struct` via `#[behaviour(ignore)]`. See
+  [PR 2842].
+
+[PR 2842]: https://github.com/libp2p/rust-libp2p/pull/2842
+
 # 0.29.0
 
 - Generate `NetworkBehaviour::OutEvent` if not provided through `#[behaviour(out_event =

swarm-derive/src/lib.rs

@@ -70,13 +70,6 @@ fn build_struct(ast: &DeriveInput, data_struct: &DataStruct) -> TokenStream {
         quote! {<#(#lf,)* #(#tp,)* #(#cst,)*>}
     };
 
-    // The fields of the struct we are interested in (no ignored fields).
-    let data_struct_fields = data_struct
-        .fields
-        .iter()
-        .filter(|f| !is_ignored(f))
-        .collect::<Vec<_>>();
-
     let (out_event_name, out_event_definition, out_event_from_clauses) = {
         // If we find a `#[behaviour(out_event = "Foo")]` attribute on the
         // struct, we set `Foo` as the out event. If not, the `OutEvent` is
@@ -102,7 +95,8 @@ fn build_struct(ast: &DeriveInput, data_struct: &DataStruct) -> TokenStream {
             // User provided `OutEvent`.
             Some(name) => {
                 let definition = None;
-                let from_clauses = data_struct_fields
+                let from_clauses = data_struct
+                    .fields
                     .iter()
                     .map(|field| {
                         let ty = &field.ty;
@@ -115,7 +109,8 @@ fn build_struct(ast: &DeriveInput, data_struct: &DataStruct) -> TokenStream {
             None => {
                 let name: syn::Type = syn::parse_str(&(ast.ident.to_string() + "Event")).unwrap();
                 let definition = {
-                    let fields = data_struct_fields
+                    let fields = data_struct
+                        .fields
                         .iter()
                         .map(|field| {
                             let variant: syn::Variant = syn::parse_str(
@@ -152,7 +147,8 @@ fn build_struct(ast: &DeriveInput, data_struct: &DataStruct) -> TokenStream {
 
     // Build the `where ...` clause of the trait implementation.
     let where_clause = {
-        let additional = data_struct_fields
+        let additional = data_struct
+            .fields
             .iter()
             .map(|field| {
                 let ty = &field.ty;
@@ -174,7 +170,8 @@ fn build_struct(ast: &DeriveInput, data_struct: &DataStruct) -> TokenStream {
 
     // Build the list of statements to put in the body of `addresses_of_peer()`.
     let addresses_of_peer_stmts = {
-        data_struct_fields
+        data_struct
+            .fields
             .iter()
             .enumerate()
             .map(move |(field_n, field)| match field.ident {
@@ -185,7 +182,7 @@ fn build_struct(ast: &DeriveInput, data_struct: &DataStruct) -> TokenStream {
 
     // Build the list of statements to put in the body of `inject_connection_established()`.
     let inject_connection_established_stmts = {
-        data_struct_fields.iter().enumerate().map(move |(field_n, field)| {
+        data_struct.fields.iter().enumerate().map(move |(field_n, field)| {
             match field.ident {
                 Some(ref i) => quote!{ self.#i.inject_connection_established(peer_id, connection_id, endpoint, errors, other_established); },
                 None => quote!{ self.#field_n.inject_connection_established(peer_id, connection_id, endpoint, errors, other_established); },
@@ -195,7 +192,7 @@ fn build_struct(ast: &DeriveInput, data_struct: &DataStruct) -> TokenStream {
 
     // Build the list of statements to put in the body of `inject_address_change()`.
     let inject_address_change_stmts = {
-        data_struct_fields.iter().enumerate().map(move |(field_n, field)| {
+        data_struct.fields.iter().enumerate().map(move |(field_n, field)| {
             match field.ident {
                 Some(ref i) => quote!{ self.#i.inject_address_change(peer_id, connection_id, old, new); },
                 None => quote!{ self.#field_n.inject_address_change(peer_id, connection_id, old, new); },
@@ -205,7 +202,7 @@ fn build_struct(ast: &DeriveInput, data_struct: &DataStruct) -> TokenStream {
 
     // Build the list of statements to put in the body of `inject_connection_closed()`.
     let inject_connection_closed_stmts = {
-        data_struct_fields
+        data_struct.fields
             .iter()
             .enumerate()
             // The outmost handler belongs to the last behaviour.
@@ -234,7 +231,8 @@ fn build_struct(ast: &DeriveInput, data_struct: &DataStruct) -> TokenStream {
 
     // Build the list of statements to put in the body of `inject_dial_failure()`.
     let inject_dial_failure_stmts = {
-        data_struct_fields
+        data_struct
+            .fields
             .iter()
             .enumerate()
             // The outmost handler belongs to the last behaviour.
@@ -268,7 +266,7 @@ fn build_struct(ast: &DeriveInput, data_struct: &DataStruct) -> TokenStream {
 
     // Build the list of statements to put in the body of `inject_listen_failure()`.
     let inject_listen_failure_stmts = {
-        data_struct_fields
+        data_struct.fields
             .iter()
             .enumerate()
             .rev()
@@ -296,7 +294,8 @@ fn build_struct(ast: &DeriveInput, data_struct: &DataStruct) -> TokenStream {
 
     // Build the list of statements to put in the body of `inject_new_listener()`.
     let inject_new_listener_stmts = {
-        data_struct_fields
+        data_struct
+            .fields
             .iter()
             .enumerate()
             .map(move |(field_n, field)| match field.ident {
@@ -307,7 +306,8 @@ fn build_struct(ast: &DeriveInput, data_struct: &DataStruct) -> TokenStream {
 
     // Build the list of statements to put in the body of `inject_new_listen_addr()`.
     let inject_new_listen_addr_stmts = {
-        data_struct_fields
+        data_struct
+            .fields
             .iter()
             .enumerate()
             .map(move |(field_n, field)| match field.ident {
@@ -318,7 +318,8 @@ fn build_struct(ast: &DeriveInput, data_struct: &DataStruct) -> TokenStream {
 
     // Build the list of statements to put in the body of `inject_expired_listen_addr()`.
     let inject_expired_listen_addr_stmts = {
-        data_struct_fields
+        data_struct
+            .fields
             .iter()
             .enumerate()
             .map(move |(field_n, field)| match field.ident {
@@ -329,7 +330,8 @@ fn build_struct(ast: &DeriveInput, data_struct: &DataStruct) -> TokenStream {
 
     // Build the list of statements to put in the body of `inject_new_external_addr()`.
     let inject_new_external_addr_stmts = {
-        data_struct_fields
+        data_struct
+            .fields
             .iter()
             .enumerate()
             .map(move |(field_n, field)| match field.ident {
@@ -340,7 +342,8 @@ fn build_struct(ast: &DeriveInput, data_struct: &DataStruct) -> TokenStream {
 
     // Build the list of statements to put in the body of `inject_expired_external_addr()`.
     let inject_expired_external_addr_stmts = {
-        data_struct_fields
+        data_struct
+            .fields
             .iter()
             .enumerate()
             .map(move |(field_n, field)| match field.ident {
@@ -351,7 +354,8 @@ fn build_struct(ast: &DeriveInput, data_struct: &DataStruct) -> TokenStream {
 
     // Build the list of statements to put in the body of `inject_listener_error()`.
     let inject_listener_error_stmts = {
-        data_struct_fields
+        data_struct
+            .fields
             .iter()
             .enumerate()
             .map(move |(field_n, field)| match field.ident {
@@ -362,7 +366,8 @@ fn build_struct(ast: &DeriveInput, data_struct: &DataStruct) -> TokenStream {
 
     // Build the list of statements to put in the body of `inject_listener_closed()`.
     let inject_listener_closed_stmts = {
-        data_struct_fields
+        data_struct
+            .fields
             .iter()
             .enumerate()
             .map(move |(field_n, field)| match field.ident {
@@ -375,14 +380,14 @@ fn build_struct(ast: &DeriveInput, data_struct: &DataStruct) -> TokenStream {
     //
     // The event type is a construction of nested `#either_ident`s of the events of the children.
     // We call `inject_event` on the corresponding child.
-    let inject_node_event_stmts = data_struct_fields.iter().enumerate().enumerate().map(|(enum_n, (field_n, field))| {
+    let inject_node_event_stmts = data_struct.fields.iter().enumerate().enumerate().map(|(enum_n, (field_n, field))| {
         let mut elem = if enum_n != 0 {
             quote!{ #either_ident::Second(ev) }
         } else {
             quote!{ ev }
         };
 
-        for _ in 0 .. data_struct_fields.len() - 1 - enum_n {
+        for _ in 0 .. data_struct.fields.len() - 1 - enum_n {
             elem = quote!{ #either_ident::First(#elem) };
         }
 
@@ -395,7 +400,7 @@ fn build_struct(ast: &DeriveInput, data_struct: &DataStruct) -> TokenStream {
     // The [`ConnectionHandler`] associated type.
     let connection_handler_ty = {
         let mut ph_ty = None;
-        for field in data_struct_fields.iter() {
+        for field in data_struct.fields.iter() {
             let ty = &field.ty;
             let field_info = quote! { <#ty as #trait_to_impl>::ConnectionHandler };
             match ph_ty {
@@ -412,7 +417,7 @@ fn build_struct(ast: &DeriveInput, data_struct: &DataStruct) -> TokenStream {
     let new_handler = {
         let mut out_handler = None;
 
-        for (field_n, field) in data_struct_fields.iter().enumerate() {
+        for (field_n, field) in data_struct.fields.iter().enumerate() {
             let field_name = match field.ident {
                 Some(ref i) => quote! { self.#i },
                 None => quote! { self.#field_n },
@@ -436,7 +441,7 @@ fn build_struct(ast: &DeriveInput, data_struct: &DataStruct) -> TokenStream {
     // List of statements to put in `poll()`.
     //
     // We poll each child one by one and wrap around the output.
-    let poll_stmts = data_struct_fields.iter().enumerate().map(|(field_n, field)| {
+    let poll_stmts = data_struct.fields.iter().enumerate().map(|(field_n, field)| {
         let field = field
             .ident
             .clone()
@@ -447,7 +452,7 @@ fn build_struct(ast: &DeriveInput, data_struct: &DataStruct) -> TokenStream {
         } else {
             quote!{ event }
         };
-        for _ in 0 .. data_struct_fields.len() - 1 - field_n {
+        for _ in 0 .. data_struct.fields.len() - 1 - field_n {
             wrapped_event = quote!{ #either_ident::First(#wrapped_event) };
         }
 
@@ -458,7 +463,7 @@ fn build_struct(ast: &DeriveInput, data_struct: &DataStruct) -> TokenStream {
         let provided_handler_and_new_handlers = {
             let mut out_handler = None;
 
-            for (f_n, f) in data_struct_fields.iter().enumerate() {
+            for (f_n, f) in data_struct.fields.iter().enumerate() {
                 let f_name = match f.ident {
                     Some(ref i) => quote! { self.#i },
                     None => quote! { self.#f_n },
@@ -637,19 +642,3 @@ fn get_meta_items(attr: &syn::Attribute) -> Option<Vec<syn::NestedMeta>> {
         None
     }
 }
-
-/// Returns true if a field is marked as ignored by the user.
-fn is_ignored(field: &syn::Field) -> bool {
-    for meta_items in field.attrs.iter().filter_map(get_meta_items) {
-        for meta_item in meta_items {
-            match meta_item {
-                syn::NestedMeta::Meta(syn::Meta::Path(ref m)) if m.is_ident("ignore") => {
-                    return true;
-                }
-                _ => (),
-            }
-        }
-    }
-
-    false
-}

swarm-derive/tests/test.rs

@@ -83,8 +83,6 @@ fn three_fields() {
         ping: libp2p::ping::Ping,
         identify: libp2p::identify::Identify,
         kad: libp2p::kad::Kademlia<libp2p::kad::record::store::MemoryStore>,
-        #[behaviour(ignore)]
-        foo: String,
     }
 
     #[allow(dead_code)]
@@ -103,30 +101,6 @@ fn three_fields() {
     }
 }
 
-#[test]
-fn three_fields_non_last_ignored() {
-    #[allow(dead_code)]
-    #[derive(NetworkBehaviour)]
-    struct Foo {
-        ping: libp2p::ping::Ping,
-        #[behaviour(ignore)]
-        identify: String,
-        kad: libp2p::kad::Kademlia<libp2p::kad::record::store::MemoryStore>,
-    }
-
-    #[allow(dead_code)]
-    #[allow(unreachable_code)]
-    fn foo() {
-        let _out_event: <Foo as NetworkBehaviour>::OutEvent = unimplemented!();
-        match _out_event {
-            FooEvent::Ping(libp2p::ping::Event { .. }) => {}
-            FooEvent::Kad(event) => {
-                let _: libp2p::kad::KademliaEvent = event;
-            }
-        }
-    }
-}
-
 #[test]
 fn custom_event() {
     #[allow(dead_code)]
@@ -359,28 +333,6 @@ fn custom_event_with_either() {
     }
 }
 
-#[test]
-fn mixed_field_order() {
-    struct Foo {}
-
-    #[derive(NetworkBehaviour)]
-    pub struct Behaviour {
-        #[behaviour(ignore)]
-        _foo: Foo,
-        _ping: libp2p::ping::Ping,
-        #[behaviour(ignore)]
-        _foo2: Foo,
-        _identify: libp2p::identify::Identify,
-        #[behaviour(ignore)]
-        _foo3: Foo,
-    }
-
-    #[allow(dead_code)]
-    fn behaviour() {
-        require_net_behaviour::<Behaviour>();
-    }
-}
-
 #[test]
 fn generated_out_event_derive_debug() {
     #[allow(dead_code)]

swarm/src/behaviour.rs

@@ -117,41 +117,6 @@ pub(crate) type THandlerOutEvent<THandler> =
 ///   }
 /// }
 /// ```
-///
-/// Struct members that don't implement [`NetworkBehaviour`] must be annotated with
-/// `#[behaviour(ignore)]`.
-///
-/// ``` rust
-/// # use libp2p::identify::{Identify, IdentifyEvent};
-/// # use libp2p::ping::{Ping, PingEvent};
-/// # use libp2p::NetworkBehaviour;
-/// #[derive(NetworkBehaviour)]
-/// #[behaviour(out_event = "Event")]
-/// struct MyBehaviour {
-///   identify: Identify,
-///   ping: Ping,
-///
-///   #[behaviour(ignore)]
-///   some_string: String,
-/// }
-/// #
-/// # enum Event {
-/// #   Identify(IdentifyEvent),
-/// #   Ping(PingEvent),
-/// # }
-/// #
-/// # impl From<IdentifyEvent> for Event {
-/// #   fn from(event: IdentifyEvent) -> Self {
-/// #     Self::Identify(event)
-/// #   }
-/// # }
-/// #
-/// # impl From<PingEvent> for Event {
-/// #   fn from(event: PingEvent) -> Self {
-/// #     Self::Ping(event)
-/// #   }
-/// # }
-/// ```
 pub trait NetworkBehaviour: 'static {
     /// Handler for all the protocols the network behaviour supports.
     type ConnectionHandler: IntoConnectionHandler;