tokio: bump MSRV to 1.56 (#5559)

.clippy.toml

@@ -1 +1 @@
-msrv = "1.49"
+msrv = "1.56"

.github/workflows/ci.yml

@@ -21,7 +21,7 @@ env:
   # - tokio-util/Cargo.toml
   # - tokio-test/Cargo.toml
   # - tokio-stream/Cargo.toml
-  rust_min: 1.49.0
+  rust_min: 1.56.0
 
 defaults:
   run:

README.md

@@ -187,7 +187,20 @@ 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 1.49.0.
+released at least six months ago. The current MSRV is 1.56.0.
+
+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
+ * 1.17 to 1.26 - Rust 1.49
+ * 1.15 to 1.16 - Rust 1.46
+ * 1.0 to 1.14 - Rust 1.45
+
+Note that although we try to avoid the situation where a dependency transitively
+increases the MSRV of Tokio, we do not guarantee that this does not happen.
+However, every minor release will have some set of versions of dependencies that
+works with the MSRV of that minor release.
 
 ## Release schedule
 
@@ -202,9 +215,9 @@ warrants a patch release with a fix for the bug, it will be backported and
 released as a new patch release for each LTS minor version. Our current LTS
 releases are:
 
- * `1.18.x` - LTS release until June 2023
- * `1.20.x` - LTS release until September 2023.
- * `1.25.x` - LTS release until March 2024
+ * `1.18.x` - LTS release until June 2023. (MSRV 1.49)
+ * `1.20.x` - LTS release until September 2023. (MSRV 1.49)
+ * `1.25.x` - LTS release until March 2024. (MSRV 1.49)
 
 Each LTS release will continue to receive backported fixes for at least a year.
 If you wish to use a fixed minor release in your project, we recommend that you

tokio-macros/Cargo.toml

@@ -6,7 +6,7 @@ name = "tokio-macros"
 # - Create "tokio-macros-1.x.y" git tag.
 version = "1.8.2"
 edition = "2018"
-rust-version = "1.49"
+rust-version = "1.56"
 authors = ["Tokio Contributors <team@tokio.rs>"]
 license = "MIT"
 repository = "https://github.com/tokio-rs/tokio"

tokio-stream/Cargo.toml

@@ -6,7 +6,7 @@ name = "tokio-stream"
 # - Create "tokio-stream-0.1.x" git tag.
 version = "0.1.12"
 edition = "2018"
-rust-version = "1.49"
+rust-version = "1.56"
 authors = ["Tokio Contributors <team@tokio.rs>"]
 license = "MIT"
 repository = "https://github.com/tokio-rs/tokio"

tokio-test/Cargo.toml

@@ -6,7 +6,7 @@ name = "tokio-test"
 # - Create "tokio-test-0.4.x" git tag.
 version = "0.4.2"
 edition = "2018"
-rust-version = "1.49"
+rust-version = "1.56"
 authors = ["Tokio Contributors <team@tokio.rs>"]
 license = "MIT"
 repository = "https://github.com/tokio-rs/tokio"

tokio-util/Cargo.toml

@@ -6,7 +6,7 @@ name = "tokio-util"
 # - Create "tokio-util-0.7.x" git tag.
 version = "0.7.7"
 edition = "2018"
-rust-version = "1.49"
+rust-version = "1.56"
 authors = ["Tokio Contributors <team@tokio.rs>"]
 license = "MIT"
 repository = "https://github.com/tokio-rs/tokio"

tokio-util/src/sync/cancellation_token/tree_node.rs

@@ -239,11 +239,7 @@ fn remove_child(parent: &mut Inner, mut node: MutexGuard<'_, Inner>) {
 
     let len = parent.children.len();
     if 4 * len <= parent.children.capacity() {
-        // equal to:
-        //    parent.children.shrink_to(2 * len);
-        // but shrink_to was not yet stabilized in our minimal compatible version
-        let old_children = std::mem::replace(&mut parent.children, Vec::with_capacity(2 * len));
-        parent.children.extend(old_children);
+        parent.children.shrink_to(2 * len);
     }
 }
 

tokio/Cargo.toml

@@ -7,8 +7,8 @@ name = "tokio"
 # - Update CHANGELOG.md.
 # - Create "v1.x.y" git tag.
 version = "1.26.0"
-edition = "2018"
-rust-version = "1.49"
+edition = "2021"
+rust-version = "1.56"
 authors = ["Tokio Contributors <team@tokio.rs>"]
 license = "MIT"
 readme = "README.md"

tokio/README.md

@@ -187,7 +187,20 @@ 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 1.49.0.
+released at least six months ago. The current MSRV is 1.56.0.
+
+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
+ * 1.17 to 1.26 - Rust 1.49
+ * 1.15 to 1.16 - Rust 1.46
+ * 1.0 to 1.14 - Rust 1.45
+
+Note that although we try to avoid the situation where a dependency transitively
+increases the MSRV of Tokio, we do not guarantee that this does not happen.
+However, every minor release will have some set of versions of dependencies that
+works with the MSRV of that minor release.
 
 ## Release schedule
 
@@ -202,9 +215,9 @@ warrants a patch release with a fix for the bug, it will be backported and
 released as a new patch release for each LTS minor version. Our current LTS
 releases are:
 
- * `1.18.x` - LTS release until June 2023
- * `1.20.x` - LTS release until September 2023.
- * `1.25.x` - LTS release until March 2024
+ * `1.18.x` - LTS release until June 2023. (MSRV 1.49)
+ * `1.20.x` - LTS release until September 2023. (MSRV 1.49)
+ * `1.25.x` - LTS release until March 2024. (MSRV 1.49)
 
 Each LTS release will continue to receive backported fixes for at least a year.
 If you wish to use a fixed minor release in your project, we recommend that you

tokio/build.rs

@@ -10,13 +10,6 @@ const CONST_THREAD_LOCAL_PROBE: &str = r#"
 }
 "#;
 
-const ADDR_OF_PROBE: &str = r#"
-{
-    let my_var = 10;
-    ::std::ptr::addr_of!(my_var)
-}
-"#;
-
 const CONST_MUTEX_NEW_PROBE: &str = r#"
 {
     static MY_MUTEX: ::std::sync::Mutex<i32> = ::std::sync::Mutex::new(1);
@@ -53,7 +46,6 @@ const TARGET_ATOMIC_U64_PROBE: &str = r#"
 
 fn main() {
     let mut enable_const_thread_local = false;
-    let mut enable_addr_of = false;
     let mut enable_target_has_atomic = false;
     let mut enable_const_mutex_new = false;
     let mut enable_as_fd = false;
@@ -81,21 +73,6 @@ fn main() {
                 }
             }
 
-            // The `addr_of` and `addr_of_mut` macros were stabilized in 1.51.
-            if ac.probe_rustc_version(1, 52) {
-                enable_addr_of = true;
-            } else if ac.probe_rustc_version(1, 51) {
-                // This compiler claims to be 1.51, but there are some nightly
-                // compilers that claim to be 1.51 without supporting the
-                // feature. Explicitly probe to check if code using them
-                // compiles.
-                //
-                // The oldest nightly that supports the feature is 2021-01-31.
-                if ac.probe_expression(ADDR_OF_PROBE) {
-                    enable_addr_of = true;
-                }
-            }
-
             // The `target_has_atomic` cfg was stabilized in 1.60.
             if ac.probe_rustc_version(1, 61) {
                 enable_target_has_atomic = true;
@@ -167,14 +144,6 @@ fn main() {
         autocfg::emit("tokio_no_const_thread_local")
     }
 
-    if !enable_addr_of {
-        // To disable this feature on compilers that support it, you can
-        // explicitly pass this flag with the following environment variable:
-        //
-        // RUSTFLAGS="--cfg tokio_no_addr_of"
-        autocfg::emit("tokio_no_addr_of")
-    }
-
     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:

tokio/src/macros/addr_of.rs

@@ -1,7 +1,6 @@
 //! This module defines a macro that lets you go from a raw pointer to a struct
 //! to a raw pointer to a field of the struct.
 
-#[cfg(not(tokio_no_addr_of))]
 macro_rules! generate_addr_of_methods {
     (
     impl<$($gen:ident)*> $struct_name:ty {$(
@@ -21,33 +20,3 @@ macro_rules! generate_addr_of_methods {
         )*}
     };
 }
-
-// The `addr_of_mut!` macro is only available for MSRV at least 1.51.0. This
-// version of the macro uses a workaround for older versions of rustc.
-#[cfg(tokio_no_addr_of)]
-macro_rules! generate_addr_of_methods {
-    (
-    impl<$($gen:ident)*> $struct_name:ty {$(
-        $(#[$attrs:meta])*
-        $vis:vis unsafe fn $fn_name:ident(self: NonNull<Self>) -> NonNull<$field_type:ty> {
-            &self$(.$field_name:tt)+
-        }
-    )*}
-    ) => {
-        impl<$($gen)*> $struct_name {$(
-            $(#[$attrs])*
-            $vis unsafe fn $fn_name(me: ::core::ptr::NonNull<Self>) -> ::core::ptr::NonNull<$field_type> {
-                let me = me.as_ptr();
-                let me_u8 = me as *mut u8;
-
-                let field_offset = {
-                    let me_ref = &*me;
-                    let field_ref_u8 = (&me_ref $(.$field_name)+ ) as *const $field_type as *const u8;
-                    field_ref_u8.offset_from(me_u8)
-                };
-
-                ::core::ptr::NonNull::new_unchecked(me_u8.offset(field_offset).cast())
-            }
-        )*}
-    };
-}

tokio/src/net/tcp/listener.rs

@@ -5,7 +5,6 @@ cfg_not_wasi! {
     use crate::net::{to_socket_addrs, ToSocketAddrs};
 }
 
-use std::convert::TryFrom;
 use std::fmt;
 use std::io;
 use std::net::{self, SocketAddr};

tokio/src/net/tcp/stream.rs

@@ -8,7 +8,6 @@ use crate::io::{AsyncRead, AsyncWrite, Interest, PollEvented, ReadBuf, Ready};
 use crate::net::tcp::split::{split, ReadHalf, WriteHalf};
 use crate::net::tcp::split_owned::{split_owned, OwnedReadHalf, OwnedWriteHalf};
 
-use std::convert::TryFrom;
 use std::fmt;
 use std::io;
 use std::net::{Shutdown, SocketAddr};

tokio/src/net/udp.rs

@@ -1,7 +1,6 @@
 use crate::io::{Interest, PollEvented, ReadBuf, Ready};
 use crate::net::{to_socket_addrs, ToSocketAddrs};
 
-use std::convert::TryFrom;
 use std::fmt;
 use std::io;
 use std::net::{self, Ipv4Addr, Ipv6Addr, SocketAddr};

tokio/src/net/unix/datagram/socket.rs

@@ -1,7 +1,6 @@
 use crate::io::{Interest, PollEvented, ReadBuf, Ready};
 use crate::net::unix::SocketAddr;
 
-use std::convert::TryFrom;
 use std::fmt;
 use std::io;
 use std::net::Shutdown;

tokio/src/net/unix/listener.rs

@@ -1,7 +1,6 @@
 use crate::io::{Interest, PollEvented};
 use crate::net::unix::{SocketAddr, UnixStream};
 
-use std::convert::TryFrom;
 use std::fmt;
 use std::io;
 #[cfg(not(tokio_no_as_fd))]

tokio/src/net/unix/stream.rs

@@ -5,7 +5,6 @@ use crate::net::unix::split_owned::{split_owned, OwnedReadHalf, OwnedWriteHalf};
 use crate::net::unix::ucred::{self, UCred};
 use crate::net::unix::SocketAddr;
 
-use std::convert::TryFrom;
 use std::fmt;
 use std::io::{self, Read, Write};
 use std::net::Shutdown;

tokio/src/process/mod.rs

@@ -156,7 +156,6 @@
 //! ```no_run
 //! use tokio::join;
 //! use tokio::process::Command;
-//! use std::convert::TryInto;
 //! use std::process::Stdio;
 //!
 //! #[tokio::main]
@@ -245,7 +244,6 @@ mod kill;
 use crate::io::{AsyncRead, AsyncWrite, ReadBuf};
 use crate::process::kill::Kill;
 
-use std::convert::TryInto;
 use std::ffi::OsStr;
 use std::future::Future;
 use std::io;

tokio/src/runtime/metrics/batch.rs

@@ -1,6 +1,5 @@
 use crate::runtime::WorkerMetrics;
 
-use std::convert::TryFrom;
 use std::sync::atomic::Ordering::Relaxed;
 use std::time::Instant;
 

tokio/src/runtime/time/source.rs

@@ -1,7 +1,5 @@
 use crate::time::{Clock, Duration, Instant};
 
-use std::convert::TryInto;
-
 /// A structure which handles conversion from Instants to u64 timestamps.
 #[derive(Debug)]
 pub(crate) struct TimeSource {

tokio/src/signal/windows/sys.rs

@@ -1,4 +1,3 @@
-use std::convert::TryFrom;
 use std::io;
 use std::sync::Once;
 

tokio/src/time/instant.rs

@@ -188,7 +188,7 @@ impl ops::Sub<Duration> for Instant {
     type Output = Instant;
 
     fn sub(self, rhs: Duration) -> Instant {
-        Instant::from_std(self.std - rhs)
+        Instant::from_std(std::time::Instant::sub(self.std, rhs))
     }
 }
 

tokio/src/time/interval.rs

@@ -2,10 +2,10 @@ use crate::future::poll_fn;
 use crate::time::{sleep_until, Duration, Instant, Sleep};
 use crate::util::trace;
 
+use std::future::Future;
 use std::panic::Location;
 use std::pin::Pin;
 use std::task::{Context, Poll};
-use std::{convert::TryInto, future::Future};
 
 /// Creates new [`Interval`] that yields with interval of `period`. The first
 /// tick completes immediately. The default [`MissedTickBehavior`] is

tokio/src/util/slab.rs

@@ -560,7 +560,7 @@ impl<T> Slots<T> {
         assert!(slot >= base, "unexpected pointer");
 
         let idx = (slot - base) / width;
-        assert!(idx < self.slots.len() as usize);
+        assert!(idx < self.slots.len());
 
         idx
     }