Split feature "sync" into "rtu-sync" and "tcp-sync"

This is required to avoid an unused tokio-serial dependency that is
only needed for "rtu-sync" but not for "rtu" (async).

CHANGELOG.md

@@ -3,6 +3,10 @@
 
 # Changelog
 
+## v0.6.0 (Unreleased)
+
+- Features: Replace "sync" with "rtu-sync" and "tcp-sync" respectively
+
 ## v0.5.3 (2022-06-22)
 
 - Fix (RTU/sync): Execute SerialStream::open within an async runtime [#116](https://github.com/slowtec/tokio-modbus/pull/116)

Cargo.toml

@@ -31,28 +31,31 @@ socket2 = { version = "0.4.7", optional = true, default-features = false }
 tokio = { version = "1.21.2", default-features = false }
 # Disable default-features to exclude unused dependency on libudev
 tokio-serial = { version = "5.4.3", optional = true, default-features = false }
-tokio-util = { version = "0.7.4", features = ["codec"] }
+tokio-util = { version = "0.7.4", default-features = false, features = ["codec"] }
 
 [dev-dependencies]
 env_logger = "0.9.1"
 futures = "0.3.25"
-tokio = { version = "1.21.2", features = ["net", "macros", "io-util", "rt", "time"] }
+tokio = { version = "1.21.2", features = ["net", "macros", "io-util", "rt-multi-thread", "time"] }
+tokio-serial = { version = "5.4.3", default-features = false }
 
 [features]
-default = ["tcp", "rtu"]
-rtu = ["tokio-serial", "futures-util/sink"]
+default = ["rtu", "tcp"]
+rtu = ["futures-util/sink"]
 tcp = ["tokio/net", "futures-util/sink"]
-sync = ["tokio/rt"]
-server = ["futures", "socket2/all", "tokio/macros", "tokio/rt", "tokio/rt-multi-thread"]
-tcp-server-unstable = ["tcp", "server"]
+rtu-sync = ["rtu", "tokio-serial"]
+tcp-sync = ["tcp"]
+server = ["futures"]
+rtu-server = ["rtu", "server", "tokio/macros", "tokio-serial"]
+tcp-server-unstable = ["tcp", "server", "socket2/all", "tokio/macros", "tokio/rt-multi-thread"]
 
 [badges]
 maintenance = { status = "actively-developed" }
 
 [[example]]
 name = "rtu-client-sync"
 path = "examples/rtu-client-sync.rs"
-required-features = ["rtu", "sync"]
+required-features = ["rtu-sync"]
 
 [[example]]
 name = "rtu-client"
@@ -62,7 +65,7 @@ required-features = ["rtu"]
 [[example]]
 name = "rtu-server"
 path = "examples/rtu-server.rs"
-required-features = ["rtu", "server"]
+required-features = ["rtu-server"]
 
 [[example]]
 name = "tcp-client-custom-fn"
@@ -72,7 +75,7 @@ required-features = ["tcp"]
 [[example]]
 name = "tcp-client-sync"
 path = "examples/tcp-client-sync.rs"
-required-features = ["tcp", "sync"]
+required-features = ["tcp-sync"]
 
 [[example]]
 name = "tcp-client"
@@ -82,4 +85,4 @@ required-features = ["tcp"]
 [[example]]
 name = "tcp-server"
 path = "examples/tcp-server.rs"
-required-features = ["tcp", "server", "tcp-server-unstable"]
+required-features = ["tcp-server-unstable"]

src/client/mod.rs

@@ -12,15 +12,15 @@ use async_trait::async_trait;
 
 use crate::{frame::*, slave::*};
 
-#[cfg(feature = "sync")]
-pub mod sync;
-
 #[cfg(feature = "rtu")]
 pub mod rtu;
 
 #[cfg(feature = "tcp")]
 pub mod tcp;
 
+#[cfg(any(feature = "rtu-sync", feature = "tcp-sync"))]
+pub mod sync;
+
 /// Transport independent asynchronous client trait
 #[async_trait]
 pub trait Client: SlaveContext + Send + Debug {

src/client/sync/mod.rs

@@ -3,15 +3,12 @@
 
 //! Synchronous Modbus client
 
-// TODO: Add missing documentation
 #![allow(missing_docs)]
 
-/// RTU client connections
-#[cfg(feature = "rtu")]
+#[cfg(feature = "rtu-sync")]
 pub mod rtu;
 
-/// TCP client connections
-#[cfg(feature = "tcp")]
+#[cfg(feature = "tcp-sync")]
 pub mod tcp;
 
 use super::{

src/lib.rs

@@ -5,6 +5,9 @@
 #![warn(rust_2021_compatibility)]
 #![warn(missing_debug_implementations)]
 #![warn(unreachable_pub)]
+#![warn(clippy::cast_lossless)]
+// TODO (v0.6): Decorate functions with #[must_use]
+//#![warn(clippy::must_use_candidate)]
 #![cfg_attr(not(test), warn(unsafe_code))]
 #![warn(clippy::all)]
 #![warn(clippy::cast_lossless)]

src/prelude.rs

@@ -32,6 +32,12 @@ pub mod tcp {
 #[cfg(feature = "server")]
 pub use crate::server;
 
+#[allow(missing_docs)]
+#[cfg(any(feature = "rtu-sync", feature = "tcp-sync"))]
+pub mod sync {
+    pub use crate::client::sync::*;
+}
+
 ///////////////////////////////////////////////////////////////////
 /// Structs
 ///////////////////////////////////////////////////////////////////
@@ -43,13 +49,13 @@ pub use crate::slave::{Slave, SlaveId};
 ///////////////////////////////////////////////////////////////////
 pub use crate::client::{Client, Reader, Writer};
 
-#[cfg(feature = "sync")]
+#[cfg(any(feature = "rtu-sync", feature = "tcp-sync"))]
 pub use crate::client::sync::Client as SyncClient;
 
-#[cfg(feature = "sync")]
+#[cfg(any(feature = "rtu-sync", feature = "tcp-sync"))]
 pub use crate::client::sync::Reader as SyncReader;
 
-#[cfg(feature = "sync")]
+#[cfg(any(feature = "rtu-sync", feature = "tcp-sync"))]
 pub use crate::client::sync::Writer as SyncWriter;
 
 pub use crate::slave::SlaveContext;

src/server/mod.rs

@@ -6,7 +6,7 @@
 // TODO: Add missing documentation
 #![allow(missing_docs)]
 
-#[cfg(feature = "rtu")]
+#[cfg(feature = "rtu-server")]
 pub mod rtu;
 
 #[cfg(feature = "tcp-server-unstable")]