Auto merge of #106283 - JulianKnodt:enum_err, r=cjgillot

[rust.git] / library / std / src / path.rs

diff --git a/library/std/src/path.rs b/library/std/src/path.rs
index 999f5d3a93f267cc22c431d84185d72d1c2ebd81..19d8f1edaf4c91087036159194f1c6f8b67034c0 100644 (file)
--- a/library/std/src/path.rs
+++ b/library/std/src/path.rs
@@ -306,7 +306,7 @@ unsafe fn u8_slice_as_os_str(s: &[u8]) -> &OsStr {
     // This casts are safe as OsStr is internally a wrapper around [u8] on all
     // platforms.
     //
-    // Note that currently this relies on the special knowledge that libstd has;
+    // Note that currently this relies on the special knowledge that std has;
     // these types are single-element structs but are not marked
     // repr(transparent) or repr(C) which would make these casts not allowable
     // outside std.
@@ -1414,7 +1414,8 @@ fn _set_file_name(&mut self, file_name: &OsStr) {
         self.push(file_name);
     }
 
-    /// Updates [`self.extension`] to `extension`.
+    /// Updates [`self.extension`] to `Some(extension)` or to `None` if
+    /// `extension` is empty.
     ///
     /// Returns `false` and does nothing if [`self.file_name`] is [`None`],
     /// returns `true` and updates the extension otherwise.
@@ -1422,6 +1423,20 @@ fn _set_file_name(&mut self, file_name: &OsStr) {
     /// If [`self.extension`] is [`None`], the extension is added; otherwise
     /// it is replaced.
     ///
+    /// If `extension` is the empty string, [`self.extension`] will be [`None`]
+    /// afterwards, not `Some("")`.
+    ///
+    /// # Caveats
+    ///
+    /// The new `extension` may contain dots and will be used in its entirety,
+    /// but only the part after the final dot will be reflected in
+    /// [`self.extension`].
+    ///
+    /// If the file stem contains internal dots and `extension` is empty, part
+    /// of the old file stem will be considered the new [`self.extension`].
+    ///
+    /// See the examples below.
+    ///
     /// [`self.file_name`]: Path::file_name
     /// [`self.extension`]: Path::extension
     ///
@@ -1435,8 +1450,20 @@ fn _set_file_name(&mut self, file_name: &OsStr) {
     /// p.set_extension("force");
     /// assert_eq!(Path::new("/feel/the.force"), p.as_path());
     ///
-    /// p.set_extension("dark_side");
-    /// assert_eq!(Path::new("/feel/the.dark_side"), p.as_path());
+    /// p.set_extension("dark.side");
+    /// assert_eq!(Path::new("/feel/the.dark.side"), p.as_path());
+    ///
+    /// p.set_extension("cookie");
+    /// assert_eq!(Path::new("/feel/the.dark.cookie"), p.as_path());
+    ///
+    /// p.set_extension("");
+    /// assert_eq!(Path::new("/feel/the.dark"), p.as_path());
+    ///
+    /// p.set_extension("");
+    /// assert_eq!(Path::new("/feel/the"), p.as_path());
+    ///
+    /// p.set_extension("");
+    /// assert_eq!(Path::new("/feel/the"), p.as_path());
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn set_extension<S: AsRef<OsStr>>(&mut self, extension: S) -> bool {