Bump tokio MSRV to 1.63

.github/workflows/ci.yml

@@ -25,7 +25,7 @@ env:
   # - tokio-util/Cargo.toml
   # - tokio-test/Cargo.toml
   # - tokio-stream/Cargo.toml
-  rust_min: 1.56.0
+  rust_min: 1.63.0
 
 defaults:
   run:

README.md

@@ -187,12 +187,13 @@ When updating this, also update:
 
 Tokio will keep a rolling MSRV (minimum supported rust version) policy of **at
 least** 6 months. When increasing the MSRV, the new Rust version must have been
-released at least six months ago. The current MSRV is 1.56.0.
+released at least six months ago. The current MSRV is 1.63.0.
 
 Note that the MSRV is not increased automatically, and only as part of a minor
 release. The MSRV history for past minor releases can be found below:
 
- * 1.27 to now - Rust 1.56
+ * 1.30 to now - Rust 1.63
+ * 1.27 to 1.29 - Rust 1.56
  * 1.17 to 1.26 - Rust 1.49
  * 1.15 to 1.16 - Rust 1.46
  * 1.0 to 1.14 - Rust 1.45

tokio/Cargo.toml

@@ -8,7 +8,7 @@ name = "tokio"
 # - Create "v1.x.y" git tag.
 version = "1.29.1"
 edition = "2021"
-rust-version = "1.56"
+rust-version = "1.63"
 authors = ["Tokio Contributors <[email protected]>"]
 license = "MIT"
 readme = "README.md"
@@ -93,9 +93,6 @@ time = []
 # a few releases.
 stats = []
 
-[build-dependencies]
-autocfg = "1.1"
-
 [dependencies]
 tokio-macros = { version = "~2.1.0", path = "../tokio-macros", optional = true }
 

tokio/build.rs

@@ -1,192 +1,15 @@
-use autocfg::AutoCfg;
-
-const CONST_THREAD_LOCAL_PROBE: &str = r#"
-{
-    thread_local! {
-        static MY_PROBE: usize = const { 10 };
-    }
-
-    MY_PROBE.with(|val| *val)
-}
-"#;
-
-const CONST_MUTEX_NEW_PROBE: &str = r#"
-{
-    static MY_MUTEX: ::std::sync::Mutex<i32> = ::std::sync::Mutex::new(1);
-    *MY_MUTEX.lock().unwrap()
-}
-"#;
-
-const AS_FD_PROBE: &str = r#"
-{
-    #[allow(unused_imports)]
-    #[cfg(unix)]
-    use std::os::unix::prelude::AsFd as _;
-    #[allow(unused_imports)]
-    #[cfg(windows)]
-    use std::os::windows::prelude::AsSocket as _;
-    #[allow(unused_imports)]
-    #[cfg(target_os = "wasi")]
-    use std::os::wasi::prelude::AsFd as _;
-}
-"#;
-
-const TARGET_HAS_ATOMIC_PROBE: &str = r#"
-{
-    #[cfg(target_has_atomic = "ptr")]
-    let _ = ();
-}
-"#;
-
-const TARGET_ATOMIC_U64_PROBE: &str = r#"
-{
-    #[allow(unused_imports)]
-    use std::sync::atomic::AtomicU64 as _;
+fn emit(cfg: &str) {
+    println!("cargo:rustc-cfg={}", cfg);
 }
-"#;
 
 fn main() {
-    let mut enable_const_thread_local = false;
-    let mut enable_target_has_atomic = false;
-    let mut enable_const_mutex_new = false;
-    let mut enable_as_fd = false;
-    let mut target_needs_atomic_u64_fallback = false;
-
-    match AutoCfg::new() {
-        Ok(ac) => {
-            // These checks prefer to call only `probe_rustc_version` if that is
-            // enough to determine whether the feature is supported. This is
-            // because the `probe_expression` call involves a call to rustc,
-            // which the `probe_rustc_version` call avoids.
-
-            // Const-initialized thread locals were stabilized in 1.59.
-            if ac.probe_rustc_version(1, 60) {
-                enable_const_thread_local = true;
-            } else if ac.probe_rustc_version(1, 59) {
-                // This compiler claims to be 1.59, but there are some nightly
-                // compilers that claim to be 1.59 without supporting the
-                // feature. Explicitly probe to check if code using them
-                // compiles.
-                //
-                // The oldest nightly that supports the feature is 2021-12-06.
-                if ac.probe_expression(CONST_THREAD_LOCAL_PROBE) {
-                    enable_const_thread_local = true;
-                }
-            }
-
-            // The `target_has_atomic` cfg was stabilized in 1.60.
-            if ac.probe_rustc_version(1, 61) {
-                enable_target_has_atomic = true;
-            } else if ac.probe_rustc_version(1, 60) {
-                // This compiler claims to be 1.60, but there are some nightly
-                // compilers that claim to be 1.60 without supporting the
-                // feature. Explicitly probe to check if code using them
-                // compiles.
-                //
-                // The oldest nightly that supports the feature is 2022-02-11.
-                if ac.probe_expression(TARGET_HAS_ATOMIC_PROBE) {
-                    enable_target_has_atomic = true;
-                }
-            }
-
-            // If we can't tell using `target_has_atomic`, tell if the target
-            // has `AtomicU64` by trying to use it.
-            if !enable_target_has_atomic && !ac.probe_expression(TARGET_ATOMIC_U64_PROBE) {
-                target_needs_atomic_u64_fallback = true;
-            }
-
-            // The `Mutex::new` method was made const in 1.63.
-            if ac.probe_rustc_version(1, 64) {
-                enable_const_mutex_new = true;
-            } else if ac.probe_rustc_version(1, 63) {
-                // This compiler claims to be 1.63, but there are some nightly
-                // compilers that claim to be 1.63 without supporting the
-                // feature. Explicitly probe to check if code using them
-                // compiles.
-                //
-                // The oldest nightly that supports the feature is 2022-06-20.
-                if ac.probe_expression(CONST_MUTEX_NEW_PROBE) {
-                    enable_const_mutex_new = true;
-                }
-            }
-
-            // The `AsFd` family of traits were made stable in 1.63.
-            if ac.probe_rustc_version(1, 64) {
-                enable_as_fd = true;
-            } else if ac.probe_rustc_version(1, 63) {
-                // This compiler claims to be 1.63, but there are some nightly
-                // compilers that claim to be 1.63 without supporting the
-                // feature. Explicitly probe to check if code using them
-                // compiles.
-                //
-                // The oldest nightly that supports the feature is 2022-06-16.
-                if ac.probe_expression(AS_FD_PROBE) {
-                    enable_as_fd = true;
-                }
-            }
-        }
-
-        Err(e) => {
-            // If we couldn't detect the compiler version and features, just
-            // print a warning. This isn't a fatal error: we can still build
-            // Tokio, we just can't enable cfgs automatically.
-            println!(
-                "cargo:warning=tokio: failed to detect compiler features: {}",
-                e
-            );
-        }
-    }
-
-    if !enable_const_thread_local {
-        // To disable this feature on compilers that support it, you can
-        // explicitly pass this flag with the following environment variable:
-        //
-        // RUSTFLAGS="--cfg tokio_no_const_thread_local"
-        autocfg::emit("tokio_no_const_thread_local")
-    }
-
-    if !enable_target_has_atomic {
-        // To disable this feature on compilers that support it, you can
-        // explicitly pass this flag with the following environment variable:
-        //
-        // RUSTFLAGS="--cfg tokio_no_target_has_atomic"
-        autocfg::emit("tokio_no_target_has_atomic")
-    }
-
-    if !enable_const_mutex_new {
-        // To disable this feature on compilers that support it, you can
-        // explicitly pass this flag with the following environment variable:
-        //
-        // RUSTFLAGS="--cfg tokio_no_const_mutex_new"
-        autocfg::emit("tokio_no_const_mutex_new")
-    }
-
-    if !enable_as_fd {
-        // To disable this feature on compilers that support it, you can
-        // explicitly pass this flag with the following environment variable:
-        //
-        // RUSTFLAGS="--cfg tokio_no_as_fd"
-        autocfg::emit("tokio_no_as_fd");
-    }
-
-    if target_needs_atomic_u64_fallback {
-        // To disable this feature on compilers that support it, you can
-        // explicitly pass this flag with the following environment variable:
-        //
-        // RUSTFLAGS="--cfg tokio_no_atomic_u64"
-        autocfg::emit("tokio_no_atomic_u64")
-    }
-
     let target = ::std::env::var("TARGET").unwrap_or_default();
 
-    // We emit cfgs instead of using `target_family = "wasm"` that requires Rust 1.54.
-    // Note that these cfgs are unavailable in `Cargo.toml`.
     if target.starts_with("wasm") {
-        autocfg::emit("tokio_wasm");
         if target.contains("wasi") {
-            autocfg::emit("tokio_wasi");
+            emit("tokio_wasi");
         } else {
-            autocfg::emit("tokio_wasm_not_wasi");
+            emit("tokio_wasm_not_wasi");
         }
     }
 }

tokio/src/lib.rs

@@ -461,21 +461,24 @@ compile_error! {
 // Each condition is written all(a, not(b)). This should be read as
 // "if a, then we must also have b".
 #[cfg(any(
-    all(target_arch = "wasm32", not(tokio_wasm)),
-    all(target_arch = "wasm64", not(tokio_wasm)),
-    all(target_family = "wasm", not(tokio_wasm)),
-    all(target_os = "wasi", not(tokio_wasm)),
+    all(target_arch = "wasm32", not(target_family = "wasm")),
+    all(target_arch = "wasm64", not(target_family = "wasm")),
+    all(target_family = "wasm", not(target_family = "wasm")),
+    all(target_os = "wasi", not(target_family = "wasm")),
     all(target_os = "wasi", not(tokio_wasi)),
     all(target_os = "wasi", tokio_wasm_not_wasi),
-    all(tokio_wasm, not(any(target_arch = "wasm32", target_arch = "wasm64"))),
-    all(tokio_wasm_not_wasi, not(tokio_wasm)),
-    all(tokio_wasi, not(tokio_wasm))
+    all(
+        target_family = "wasm",
+        not(any(target_arch = "wasm32", target_arch = "wasm64"))
+    ),
+    all(tokio_wasm_not_wasi, not(target_family = "wasm")),
+    all(tokio_wasi, not(target_family = "wasm"))
 ))]
 compile_error!("Tokio's build script has incorrectly detected wasm.");
 
 #[cfg(all(
     not(tokio_unstable),
-    tokio_wasm,
+    target_family = "wasm",
     any(
         feature = "fs",
         feature = "io-std",

tokio/src/runtime/config.rs

@@ -1,4 +1,4 @@
-#![cfg_attr(any(not(feature = "full"), tokio_wasm), allow(dead_code))]
+#![cfg_attr(any(not(feature = "full"), target_family = "wasm"), allow(dead_code))]
 use crate::runtime::Callback;
 use crate::util::RngSeedGenerator;
 

tokio/src/runtime/mod.rs

@@ -175,7 +175,7 @@
 
 // At the top due to macros
 #[cfg(test)]
-#[cfg(not(tokio_wasm))]
+#[cfg(not(target_family = "wasm"))]
 #[macro_use]
 mod tests;
 

tokio/src/runtime/park.rs

@@ -67,9 +67,9 @@ impl ParkThread {
         CURRENT_THREAD_PARK_COUNT.with(|count| count.fetch_add(1, SeqCst));
 
         // Wasm doesn't have threads, so just sleep.
-        #[cfg(not(tokio_wasm))]
+        #[cfg(not(target_family = "wasm"))]
         self.inner.park_timeout(duration);
-        #[cfg(tokio_wasm)]
+        #[cfg(target_family = "wasm")]
         std::thread::sleep(duration);
     }
 

tokio/src/runtime/task/mod.rs

@@ -404,7 +404,7 @@ impl<S: Schedule> LocalNotified<S> {
 impl<S: Schedule> UnownedTask<S> {
     // Used in test of the inject queue.
     #[cfg(test)]
-    #[cfg_attr(tokio_wasm, allow(dead_code))]
+    #[cfg_attr(target_family = "wasm", allow(dead_code))]
     pub(super) fn into_notified(self) -> Notified<S> {
         Notified(self.into_task())
     }

tokio/src/sync/tests/atomic_waker.rs

@@ -37,7 +37,7 @@ fn wake_without_register() {
 }
 
 #[test]
-#[cfg(not(tokio_wasm))] // wasm currently doesn't support unwinding
+#[cfg(not(target_family = "wasm"))] // wasm currently doesn't support unwinding
 fn atomic_waker_panic_safe() {
     use std::panic;
     use std::ptr;

tokio/src/sync/tests/notify.rs

@@ -101,7 +101,7 @@ fn notify_simple() {
 }
 
 #[test]
-#[cfg(not(tokio_wasm))]
+#[cfg(not(target_family = "wasm"))]
 fn watch_test() {
     let rt = crate::runtime::Builder::new_current_thread()
         .build()

tokio/src/sync/tests/semaphore_batch.rs

@@ -177,7 +177,7 @@ fn max_permits_doesnt_panic() {
 
 #[test]
 #[should_panic]
-#[cfg(not(tokio_wasm))] // wasm currently doesn't support unwinding
+#[cfg(not(target_family = "wasm"))] // wasm currently doesn't support unwinding
 fn validates_max_permits() {
     Semaphore::new(MAX_PERMITS + 1);
 }