Remove the need for the async_trait crate by leveraging the native async fns support now in Rust as of v1.75

README.md

@@ -1,7 +1,7 @@
 # ractor
 
 <p align="center">
-    <img src="https://raw.githubusercontent.com/slawlor/ractor/main/docs/ractor_logo.svg" width="50%" /> 
+    <img src="https://raw.githubusercontent.com/slawlor/ractor/main/docs/ractor_logo.svg" width="50%" />
 </p>
 
 *Pronounced ract-er*
@@ -64,7 +64,7 @@ Install `ractor` by adding the following to your Cargo.toml dependencies.
 ractor = "0.9"
 ```
 
-The minimum supported Rust version (MSRV) of `ractor` is `1.64`
+The minimum supported Rust version (MSRV) of `ractor` is `1.64`. However to utilize the native `async fn` support in traits and not rely on the `async-trait` crate's desugaring functionliaty, you need to be on Rust version `>= 1.75`. The stabilization of `async fn` in traits [was recently added](https://blog.rust-lang.org/2023/12/21/async-fn-rpit-in-traits.html).
 
 ## Features
 
@@ -81,7 +81,7 @@ never be executed in parallel. Following the actor model leads to microservices
 An example `ping-pong` actor might be the following
 
 ```rust
-use ractor::{async_trait, cast, Actor, ActorProcessingErr, ActorRef};
+use ractor::{cast, Actor, ActorProcessingErr, ActorRef};
 
 /// [PingPong] is a basic actor that will print
 /// ping..pong.. repeatedly until some exit
@@ -114,7 +114,6 @@ impl Message {
 }
 
 // the implementation of our actor's "logic"
-#[async_trait]
 impl Actor for PingPong {
     // An actor has a message type
     type Msg = Message;

ractor/Cargo.toml

@@ -19,19 +19,20 @@ cluster = []
 tokio_runtime = ["tokio/time", "tokio/rt", "tokio/macros", "tokio/tracing"]
 
 # default = ["async-std"]
-default = ["tokio_runtime"]
+default = ["tokio_runtime", "async-trait"]
 
 [dependencies]
 ## Required dependencies
-async-trait = "0.1"
 dashmap = "5"
 futures = "0.3"
 once_cell = "1"
 rand = "0.8"
 
+## Configurable dependencies
 # Tracing feature requires --cfg=tokio_unstable
-tokio = { version = "1", features = ["sync"] }
 async-std = { version = "1", features = ["attributes"], optional = true }
+async-trait = { version = "0.1", optional = true }
+tokio = { version = "1", features = ["sync"] }
 tracing = { version = "0.1", features = ["attributes"] }
 
 [dev-dependencies]

ractor/benches/actor.rs

@@ -17,7 +17,7 @@ struct BenchActorMessage;
 #[cfg(feature = "cluster")]
 impl Message for BenchActorMessage {}
 
-#[async_trait::async_trait]
+#[cfg_attr(feature = "async-trait", ractor::async_trait)]
 impl Actor for BenchActor {
     type Msg = BenchActorMessage;
 
@@ -247,7 +247,7 @@ fn process_messages(c: &mut Criterion) {
         num_msgs: u64,
     }
 
-    #[async_trait::async_trait]
+    #[cfg_attr(feature = "async-trait", ractor::async_trait)]
     impl Actor for MessagingActor {
         type Msg = BenchActorMessage;
 

ractor/examples/counter.rs

@@ -14,7 +14,7 @@
 
 extern crate ractor;
 
-use ractor::{async_trait, call_t, Actor, ActorProcessingErr, ActorRef, RpcReplyPort};
+use ractor::{call_t, Actor, ActorProcessingErr, ActorRef, RpcReplyPort};
 
 struct Counter;
 
@@ -31,7 +31,7 @@ enum CounterMessage {
 #[cfg(feature = "cluster")]
 impl ractor::Message for CounterMessage {}
 
-#[async_trait]
+#[cfg_attr(feature = "async-trait", ractor::async_trait)]
 impl Actor for Counter {
     type Msg = CounterMessage;
 

ractor/examples/monte_carlo.rs

@@ -17,7 +17,7 @@
 
 use std::collections::HashMap;
 
-use ractor::{async_trait, cast, Actor, ActorId, ActorProcessingErr, ActorRef};
+use ractor::{cast, Actor, ActorId, ActorProcessingErr, ActorRef};
 use rand::{thread_rng, Rng};
 
 // ================== Player Actor ================== //
@@ -62,7 +62,7 @@ struct GameMessage(ActorRef<GameManagerMessage>);
 #[cfg(feature = "cluster")]
 impl ractor::Message for GameMessage {}
 
-#[async_trait]
+#[cfg_attr(feature = "async-trait", ractor::async_trait)]
 impl Actor for Game {
     type Msg = GameMessage;
 
@@ -139,7 +139,7 @@ impl GameManagerState {
     }
 }
 
-#[async_trait]
+#[cfg_attr(feature = "async-trait", ractor::async_trait)]
 impl Actor for GameManager {
     type Msg = GameManagerMessage;
 

ractor/examples/output_port.rs

@@ -15,7 +15,7 @@ extern crate ractor;
 
 use std::sync::Arc;
 
-use ractor::{async_trait, Actor, ActorProcessingErr, ActorRef, OutputPort};
+use ractor::{Actor, ActorProcessingErr, ActorRef, OutputPort};
 use tokio::time::{timeout, Duration};
 
 enum PublisherMessage {
@@ -31,7 +31,7 @@ impl ractor::Message for Output {}
 
 struct Publisher;
 
-#[async_trait]
+#[cfg_attr(feature = "async-trait", ractor::async_trait)]
 impl Actor for Publisher {
     type Msg = PublisherMessage;
 
@@ -70,7 +70,7 @@ enum SubscriberMessage {
 #[cfg(feature = "cluster")]
 impl ractor::Message for SubscriberMessage {}
 
-#[async_trait]
+#[cfg_attr(feature = "async-trait", ractor::async_trait)]
 impl Actor for Subscriber {
     type Msg = SubscriberMessage;
 

ractor/examples/philosophers.rs

@@ -20,9 +20,7 @@
 
 use std::collections::{HashMap, VecDeque};
 
-use ractor::{
-    async_trait, cast, Actor, ActorId, ActorName, ActorProcessingErr, ActorRef, RpcReplyPort,
-};
+use ractor::{cast, Actor, ActorId, ActorName, ActorProcessingErr, ActorRef, RpcReplyPort};
 use tokio::time::{Duration, Instant};
 
 // ============================ Fork Actor ============================ //
@@ -113,7 +111,7 @@ impl Fork {
     }
 }
 
-#[async_trait]
+#[cfg_attr(feature = "async-trait", ractor::async_trait)]
 impl Actor for Fork {
     type Msg = ForkMessage;
     type State = ForkState;
@@ -326,7 +324,7 @@ impl Philosopher {
     }
 }
 
-#[async_trait]
+#[cfg_attr(feature = "async-trait", ractor::async_trait)]
 impl Actor for Philosopher {
     type Msg = PhilosopherMessage;
     type State = PhilosopherState;

ractor/examples/ping_pong.rs

@@ -14,7 +14,7 @@
 
 extern crate ractor;
 
-use ractor::{async_trait, cast, Actor, ActorProcessingErr, ActorRef};
+use ractor::{cast, Actor, ActorProcessingErr, ActorRef};
 
 pub struct PingPong;
 
@@ -42,7 +42,7 @@ impl Message {
     }
 }
 
-#[async_trait]
+#[cfg_attr(feature = "async-trait", ractor::async_trait)]
 impl Actor for PingPong {
     type Msg = Message;
 

ractor/examples/supervisor.rs

@@ -11,7 +11,7 @@
 //! cargo run --example supervisor
 //! ```
 
-use ractor::{async_trait, Actor, ActorProcessingErr, ActorRef, RpcReplyPort, SupervisionEvent};
+use ractor::{Actor, ActorProcessingErr, ActorRef, RpcReplyPort, SupervisionEvent};
 
 use tokio::time::Duration;
 
@@ -97,7 +97,7 @@ enum LeafActorMessage {
 #[cfg(feature = "cluster")]
 impl ractor::Message for LeafActorMessage {}
 
-#[async_trait]
+#[cfg_attr(feature = "async-trait", ractor::async_trait)]
 impl Actor for LeafActor {
     type Msg = LeafActorMessage;
     type State = LeafActorState;
@@ -160,7 +160,7 @@ enum MidLevelActorMessage {
 #[cfg(feature = "cluster")]
 impl ractor::Message for MidLevelActorMessage {}
 
-#[async_trait]
+#[cfg_attr(feature = "async-trait", ractor::async_trait)]
 impl Actor for MidLevelActor {
     type Msg = MidLevelActorMessage;
     type State = MidLevelActorState;
@@ -240,7 +240,7 @@ enum RootActorMessage {
 #[cfg(feature = "cluster")]
 impl ractor::Message for RootActorMessage {}
 
-#[async_trait]
+#[cfg_attr(feature = "async-trait", ractor::async_trait)]
 impl Actor for RootActor {
     type Msg = RootActorMessage;
     type State = RootActorState;