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Make std::env::{set_var, remove_var} unsafe in edition 2024

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Allow calling these functions without `unsafe` blocks in editions up
until 2021, but don't trigger the `unused_unsafe` lint for `unsafe`
blocks containing these functions.

Fixes #27970.
Fixes #90308.
CC #124866.
This commit is contained in:
Tobias Bucher 2024-05-13 09:05:34 +02:00
parent e9b7aa08f7
commit 5d8f9b4dc1
18 changed files with 172 additions and 57 deletions
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54
library/std/src/env.rs
View file

@ -318,11 +318,6 @@ impl Error for VarError {
///
/// # Safety
///
/// Even though this function is currently not marked as `unsafe`, it needs to
/// be because invoking it can cause undefined behaviour. The function will be
/// marked `unsafe` in a future version of Rust. This is tracked in
/// [rust#27970](https://github.com/rust-lang/rust/issues/27970).
///
/// This function is safe to call in a single-threaded program.
///
/// In multi-threaded programs, you must ensure that are no other threads
@ -331,7 +326,7 @@ impl Error for VarError {
/// how to achieve this, but we strongly suggest not using `set_var` or
/// `remove_var` in multi-threaded programs at all.
///
/// Most C libraries, including libc itself do not advertise which functions
/// Most C libraries, including libc itself, do not advertise which functions
/// read from the environment. Even functions from the Rust standard library do
/// that, e.g. for DNS lookups from [`std::net::ToSocketAddrs`].
///
@ -353,15 +348,26 @@ impl Error for VarError {
/// use std::env;
///
/// let key = "KEY";
/// env::set_var(key, "VALUE");
/// unsafe {
/// env::set_var(key, "VALUE");
/// }
/// assert_eq!(env::var(key), Ok("VALUE".to_string()));
/// ```
#[cfg(not(bootstrap))]
#[rustc_deprecated_safe_2024]
#[stable(feature = "env", since = "1.0.0")]
pub fn set_var<K: AsRef<OsStr>, V: AsRef<OsStr>>(key: K, value: V) {
pub unsafe fn set_var<K: AsRef<OsStr>, V: AsRef<OsStr>>(key: K, value: V) {
_set_var(key.as_ref(), value.as_ref())
}
fn _set_var(key: &OsStr, value: &OsStr) {
#[cfg(bootstrap)]
#[allow(missing_docs)]
#[stable(feature = "env", since = "1.0.0")]
pub fn set_var<K: AsRef<OsStr>, V: AsRef<OsStr>>(key: K, value: V) {
unsafe { _set_var(key.as_ref(), value.as_ref()) }
}
unsafe fn _set_var(key: &OsStr, value: &OsStr) {
os_imp::setenv(key, value).unwrap_or_else(|e| {
panic!("failed to set environment variable `{key:?}` to `{value:?}`: {e}")
})
@ -371,11 +377,6 @@ fn _set_var(key: &OsStr, value: &OsStr) {
///
/// # Safety
///
/// Even though this function is currently not marked as `unsafe`, it needs to
/// be because invoking it can cause undefined behaviour. The function will be
/// marked `unsafe` in a future version of Rust. This is tracked in
/// [rust#27970](https://github.com/rust-lang/rust/issues/27970).
///
/// This function is safe to call in a single-threaded program.
///
/// In multi-threaded programs, you must ensure that are no other threads
@ -384,7 +385,7 @@ fn _set_var(key: &OsStr, value: &OsStr) {
/// how to achieve this, but we strongly suggest not using `set_var` or
/// `remove_var` in multi-threaded programs at all.
///
/// Most C libraries, including libc itself do not advertise which functions
/// Most C libraries, including libc itself, do not advertise which functions
/// read from the environment. Even functions from the Rust standard library do
/// that, e.g. for DNS lookups from [`std::net::ToSocketAddrs`].
///
@ -403,22 +404,35 @@ fn _set_var(key: &OsStr, value: &OsStr) {
///
/// # Examples
///
/// ```
/// ```no_run
/// use std::env;
///
/// let key = "KEY";
/// env::set_var(key, "VALUE");
/// unsafe {
/// env::set_var(key, "VALUE");
/// }
/// assert_eq!(env::var(key), Ok("VALUE".to_string()));
///
/// env::remove_var(key);
/// unsafe {
/// env::remove_var(key);
/// }
/// assert!(env::var(key).is_err());
/// ```
#[cfg(not(bootstrap))]
#[rustc_deprecated_safe_2024]
#[stable(feature = "env", since = "1.0.0")]
pub fn remove_var<K: AsRef<OsStr>>(key: K) {
pub unsafe fn remove_var<K: AsRef<OsStr>>(key: K) {
_remove_var(key.as_ref())
}
fn _remove_var(key: &OsStr) {
#[cfg(bootstrap)]
#[allow(missing_docs)]
#[stable(feature = "env", since = "1.0.0")]
pub fn remove_var<K: AsRef<OsStr>>(key: K) {
unsafe { _remove_var(key.as_ref()) }
}
unsafe fn _remove_var(key: &OsStr) {
os_imp::unsetenv(key)
.unwrap_or_else(|e| panic!("failed to remove environment variable `{key:?}`: {e}"))
}