Stabilize Termination and ExitCode

library/std/src/process.rs

@@ -1404,6 +1404,15 @@ impl From<fs::File> for Stdio {
 /// For proper error reporting of failed processes, print the value of `ExitStatus` or
 /// `ExitStatusError` using their implementations of [`Display`](crate::fmt::Display).
 ///
+/// # Differences from `ExitStatus`
+///
+/// `ExitCode` is intended for terminating the currently running process, via
+/// the `Termination` trait, in contrast to [`ExitStatus`], which represents the
+/// termination of a child process. These APIs are separate due to platform
+/// compatibility differences and their expected usage; it is not generally
+/// possible to exactly reproduce an ExitStatus from a child for the current
+/// process after the fact.
+///
 /// [`status`]: Command::status
 /// [`wait`]: Child::wait
 //
@@ -1636,8 +1645,16 @@ impl fmt::Display for ExitStatusError {
 #[unstable(feature = "exit_status_error", issue = "84908")]
 impl crate::error::Error for ExitStatusError {}
 
-/// This type represents the status code a process can return to its
-/// parent under normal termination.
+/// This type represents the status code the current process can return
+/// to its parent under normal termination.
+///
+/// `ExitCode` is intended to be consumed only by the standard library (via
+/// [`Termination::report()`]), and intentionally does not provide accessors like
+/// `PartialEq`, `Eq`, or `Hash`. Instead the standard library provides the
+/// canonical `SUCCESS` and `FAILURE` exit codes as well as `From<u8> for
+/// ExitCode` for constructing other arbitrary exit codes.
+///
+/// # Portability
 ///
 /// Numeric values used in this type don't have portable meanings, and
 /// different platforms may mask different amounts of them.
@@ -1648,52 +1665,78 @@ impl crate::error::Error for ExitStatusError {}
 /// [`SUCCESS`]: ExitCode::SUCCESS
 /// [`FAILURE`]: ExitCode::FAILURE
 ///
-/// **Warning**: While various forms of this were discussed in [RFC #1937],
-/// it was ultimately cut from that RFC, and thus this type is more subject
-/// to change even than the usual unstable item churn.
+/// # Differences from `ExitStatus`
+///
+/// `ExitCode` is intended for terminating the currently running process, via
+/// the `Termination` trait, in contrast to [`ExitStatus`], which represents the
+/// termination of a child process. These APIs are separate due to platform
+/// compatibility differences and their expected usage; it is not generally
+/// possible to exactly reproduce an ExitStatus from a child for the current
+/// process after the fact.
+///
+/// # Examples
+///
+/// `ExitCode` can be returned from the `main` function of a crate, as it implements
+/// [`Termination`]:
+///
+/// ```
+/// use std::process::ExitCode;
+/// # fn check_foo() -> bool { true }
 ///
-/// [RFC #1937]: https://github.com/rust-lang/rfcs/pull/1937
+/// fn main() -> ExitCode {
+///     if !check_foo() {
+///         return ExitCode::from(42);
+///     }
+///
+///     ExitCode::SUCCESS
+/// }
+/// ```
 #[derive(Clone, Copy, Debug)]
-#[unstable(feature = "process_exitcode_placeholder", issue = "48711")]
+#[stable(feature = "process_exitcode", since = "1.60.0")]
 pub struct ExitCode(imp::ExitCode);
 
-#[unstable(feature = "process_exitcode_placeholder", issue = "48711")]
+#[stable(feature = "process_exitcode", since = "1.60.0")]
 impl ExitCode {
-    /// The canonical ExitCode for successful termination on this platform.
+    /// The canonical `ExitCode` for successful termination on this platform.
     ///
     /// Note that a `()`-returning `main` implicitly results in a successful
     /// termination, so there's no need to return this from `main` unless
     /// you're also returning other possible codes.
-    #[unstable(feature = "process_exitcode_placeholder", issue = "48711")]
+    #[stable(feature = "process_exitcode", since = "1.60.0")]
     pub const SUCCESS: ExitCode = ExitCode(imp::ExitCode::SUCCESS);
 
-    /// The canonical ExitCode for unsuccessful termination on this platform.
+    /// The canonical `ExitCode` for unsuccessful termination on this platform.
     ///
     /// If you're only returning this and `SUCCESS` from `main`, consider
     /// instead returning `Err(_)` and `Ok(())` respectively, which will
     /// return the same codes (but will also `eprintln!` the error).
-    #[unstable(feature = "process_exitcode_placeholder", issue = "48711")]
+    #[stable(feature = "process_exitcode", since = "1.60.0")]
     pub const FAILURE: ExitCode = ExitCode(imp::ExitCode::FAILURE);
 }
 
 impl ExitCode {
-    // This should not be stabilized when stabilizing ExitCode, we don't know that i32 will serve
+    // This is private/perma-unstable because ExitCode is opaque; we don't know that i32 will serve
     // all usecases, for example windows seems to use u32, unix uses the 8-15th bits of an i32, we
     // likely want to isolate users anything that could restrict the platform specific
     // representation of an ExitCode
     //
     // More info: https://internals.rust-lang.org/t/mini-pre-rfc-redesigning-process-exitstatus/5426
-    /// Convert an ExitCode into an i32
-    #[unstable(feature = "process_exitcode_placeholder", issue = "48711")]
+    /// Convert an `ExitCode` into an i32
+    #[unstable(
+        feature = "process_exitcode_internals",
+        reason = "exposed only for libstd",
+        issue = "none"
+    )]
     #[inline]
+    #[doc(hidden)]
     pub fn to_i32(self) -> i32 {
         self.0.as_i32()
     }
 }
 
-#[unstable(feature = "process_exitcode_placeholder", issue = "48711")]
+#[stable(feature = "process_exitcode", since = "1.60.0")]
 impl From<u8> for ExitCode {
-    /// Construct an exit code from an arbitrary u8 value.
+    /// Construct an `ExitCode` from an arbitrary u8 value.
     fn from(code: u8) -> Self {
         ExitCode(imp::ExitCode::from(code))
     }
@@ -2031,26 +2074,27 @@ pub fn id() -> u32 {
 /// The default implementations are returning `libc::EXIT_SUCCESS` to indicate
 /// a successful execution. In case of a failure, `libc::EXIT_FAILURE` is returned.
 #[cfg_attr(not(test), lang = "termination")]
-#[unstable(feature = "termination_trait_lib", issue = "43301")]
+#[stable(feature = "termination_trait_lib", since = "1.60.0")]
 #[rustc_on_unimplemented(
     message = "`main` has invalid return type `{Self}`",
     label = "`main` can only return types that implement `{Termination}`"
 )]
 pub trait Termination {
     /// Is called to get the representation of the value as status code.
     /// This status code is returned to the operating system.
+    #[stable(feature = "termination_trait_lib", since = "1.60.0")]
     fn report(self) -> ExitCode;
 }
 
-#[unstable(feature = "termination_trait_lib", issue = "43301")]
+#[stable(feature = "termination_trait_lib", since = "1.60.0")]
 impl Termination for () {
     #[inline]
     fn report(self) -> ExitCode {
         ExitCode::SUCCESS.report()
     }
 }
 
-#[unstable(feature = "termination_trait_lib", issue = "43301")]
+#[stable(feature = "termination_trait_lib", since = "1.60.0")]
 impl<E: fmt::Debug> Termination for Result<(), E> {
     fn report(self) -> ExitCode {
         match self {
@@ -2060,14 +2104,14 @@ impl<E: fmt::Debug> Termination for Result<(), E> {
     }
 }
 
-#[unstable(feature = "termination_trait_lib", issue = "43301")]
+#[stable(feature = "termination_trait_lib", since = "1.60.0")]
 impl Termination for ! {
     fn report(self) -> ExitCode {
         self
     }
 }
 
-#[unstable(feature = "termination_trait_lib", issue = "43301")]
+#[stable(feature = "termination_trait_lib", since = "1.60.0")]
 impl<E: fmt::Debug> Termination for Result<!, E> {
     fn report(self) -> ExitCode {
         let Err(err) = self;
@@ -2076,15 +2120,15 @@ impl<E: fmt::Debug> Termination for Result<!, E> {
     }
 }
 
-#[unstable(feature = "termination_trait_lib", issue = "43301")]
+#[stable(feature = "termination_trait_lib", since = "1.60.0")]
 impl<E: fmt::Debug> Termination for Result<Infallible, E> {
     fn report(self) -> ExitCode {
         let Err(err) = self;
         Err::<!, _>(err).report()
     }
 }
 
-#[unstable(feature = "termination_trait_lib", issue = "43301")]
+#[stable(feature = "termination_trait_lib", since = "1.60.0")]
 impl Termination for ExitCode {
     #[inline]
     fn report(self) -> ExitCode {

library/test/src/lib.rs

@@ -19,8 +19,7 @@
 #![feature(bench_black_box)]
 #![feature(internal_output_capture)]
 #![feature(staged_api)]
-#![feature(termination_trait_lib)]
-#![feature(process_exitcode_placeholder)]
+#![feature(process_exitcode_internals)]
 #![feature(test)]
 #![feature(total_cmp)]
 

src/test/ui/rfcs/rfc-1937-termination-trait/termination-trait-for-exitcode.rs

@@ -1,5 +1,4 @@
 // run-pass
-#![feature(process_exitcode_placeholder)]
 
 use std::process::ExitCode;
 

src/test/ui/rfcs/rfc-1937-termination-trait/termination-trait-for-impl-termination.rs

@@ -1,4 +1,3 @@
 // run-pass
-#![feature(termination_trait_lib)]
 
 fn main() -> impl std::process::Termination { }