Rollup merge of rust-lang#126140 - eduardosm:stabilize-fs_try_exists, r=Amanieu

Rename `std::fs::try_exists` to  `std::fs::exists` and stabilize fs_try_exists

FCP completed in tracking issue.

Tracking issue: rust-lang#83186

Closes rust-lang#83186

Stabilized API:

```rust
mod fs {
    pub fn exists<P: AsRef<Path>>(path: P) -> io::Result<bool>;
}
```

Author: matthiaskrgr

library/std/src/fs.rs

@@ -2739,18 +2739,15 @@ impl AsInnerMut<fs_imp::DirBuilder> for DirBuilder {
 /// # Examples
 ///
 /// ```no_run
-/// #![feature(fs_try_exists)]
 /// use std::fs;
 ///
-/// assert!(!fs::try_exists("does_not_exist.txt").expect("Can't check existence of file does_not_exist.txt"));
-/// assert!(fs::try_exists("/root/secret_file.txt").is_err());
+/// assert!(!fs::exists("does_not_exist.txt").expect("Can't check existence of file does_not_exist.txt"));
+/// assert!(fs::exists("/root/secret_file.txt").is_err());
 /// ```
 ///
 /// [`Path::exists`]: crate::path::Path::exists
-// FIXME: stabilization should modify documentation of `exists()` to recommend this method
-// instead.
-#[unstable(feature = "fs_try_exists", issue = "83186")]
+#[stable(feature = "fs_try_exists", since = "CURRENT_RUSTC_VERSION")]
 #[inline]
-pub fn try_exists<P: AsRef<Path>>(path: P) -> io::Result<bool> {
-    fs_imp::try_exists(path.as_ref())
+pub fn exists<P: AsRef<Path>>(path: P) -> io::Result<bool> {
+    fs_imp::exists(path.as_ref())
 }

library/std/src/path.rs

@@ -2907,6 +2907,8 @@ impl Path {
     /// prevent time-of-check to time-of-use (TOCTOU) bugs. You should only use it in scenarios
     /// where those bugs are not an issue.
     ///
+    /// This is an alias for [`std::fs::exists`](crate::fs::exists).
+    ///
     /// # Examples
     ///
     /// ```no_run
@@ -2919,7 +2921,7 @@ impl Path {
     #[stable(feature = "path_try_exists", since = "1.63.0")]
     #[inline]
     pub fn try_exists(&self) -> io::Result<bool> {
-        fs::try_exists(self)
+        fs::exists(self)
     }
 
     /// Returns `true` if the path exists on disk and is pointing at a regular file.

library/std/src/sys/pal/unix/fs.rs

@@ -101,7 +101,7 @@ use libc::{
 ))]
 use libc::{dirent64, fstat64, ftruncate64, lseek64, lstat64, off64_t, open64, stat64};
 
-pub use crate::sys_common::fs::try_exists;
+pub use crate::sys_common::fs::exists;
 
 pub struct File(FileDesc);
 

library/std/src/sys/pal/unix/thread.rs

@@ -477,7 +477,7 @@ mod cgroups {
     //!   output and we don't unescape
     use crate::borrow::Cow;
     use crate::ffi::OsString;
-    use crate::fs::{try_exists, File};
+    use crate::fs::{exists, File};
     use crate::io::Read;
     use crate::io::{BufRead, BufReader};
     use crate::os::unix::ffi::OsStringExt;
@@ -555,7 +555,7 @@ mod cgroups {
         path.push("cgroup.controllers");
 
         // skip if we're not looking at cgroup2
-        if matches!(try_exists(&path), Err(_) | Ok(false)) {
+        if matches!(exists(&path), Err(_) | Ok(false)) {
             return usize::MAX;
         };
 
@@ -612,7 +612,7 @@ mod cgroups {
             path.push(&group_path);
 
             // skip if we guessed the mount incorrectly
-            if matches!(try_exists(&path), Err(_) | Ok(false)) {
+            if matches!(exists(&path), Err(_) | Ok(false)) {
                 continue;
             }
 

library/std/src/sys/pal/unsupported/fs.rs

@@ -291,7 +291,7 @@ pub fn remove_dir_all(_path: &Path) -> io::Result<()> {
     unsupported()
 }
 
-pub fn try_exists(_path: &Path) -> io::Result<bool> {
+pub fn exists(_path: &Path) -> io::Result<bool> {
     unsupported()
 }
 

library/std/src/sys/pal/windows/fs.rs

@@ -1531,7 +1531,7 @@ pub fn junction_point(original: &Path, link: &Path) -> io::Result<()> {
 }
 
 // Try to see if a file exists but, unlike `exists`, report I/O errors.
-pub fn try_exists(path: &Path) -> io::Result<bool> {
+pub fn exists(path: &Path) -> io::Result<bool> {
     // Open the file to ensure any symlinks are followed to their target.
     let mut opts = OpenOptions::new();
     // No read, write, etc access rights are needed.

library/std/src/sys_common/fs.rs

@@ -42,7 +42,7 @@ fn remove_dir_all_recursive(path: &Path) -> io::Result<()> {
     fs::remove_dir(path)
 }
 
-pub fn try_exists(path: &Path) -> io::Result<bool> {
+pub fn exists(path: &Path) -> io::Result<bool> {
     match fs::metadata(path) {
         Ok(_) => Ok(true),
         Err(error) if error.kind() == io::ErrorKind::NotFound => Ok(false),