Auto merge of #28034 - alexcrichton:new-lines, r=aturon

This commit is an implementation of [RFC 1212][rfc] which tweaks the behavior of
the `str::lines` and `BufRead::lines` iterators. Both iterators now account for
`\r\n` sequences in addition to `\n`, allowing for less surprising behavior
across platforms (especially in the `BufRead` case). Splitting *only* on the
`\n` character can still be achieved with `split('\n')` in both cases.

The `str::lines_any` function is also now deprecated as `str::lines` is a
drop-in replacement for it.

[rfc]: https://github.com/rust-lang/rfcs/blob/master/text/1212-line-endings.md

Closes #28032

1 files changed, 7 insertions, 4 deletions

diff --git a/src/libstd/io/mod.rs b/src/libstd/io/mod.rs
index 72a74c23dc8..54869807cac 100644
--- a/src/libstd/io/mod.rs
+++ b/src/libstd/io/mod.rs
@@ -1439,7 +1439,7 @@ pub trait BufRead: Read {
     ///
     /// The iterator returned from this function will yield instances of
     /// `io::Result<String>`. Each string returned will *not* have a newline
-    /// byte (the 0xA byte) at the end.
+    /// byte (the 0xA byte) or CRLF (0xD, 0xA bytes) at the end.
     ///
     /// # Examples
     ///
@@ -1763,6 +1763,9 @@ impl<B: BufRead> Iterator for Lines<B> {
             Ok(_n) => {
                 if buf.ends_with("\n") {
                     buf.pop();
+                    if buf.ends_with("\r") {
+                        buf.pop();
+                    }
                 }
                 Some(Ok(buf))
             }
@@ -1834,12 +1837,12 @@ mod tests {
 
     #[test]
     fn lines() {
-        let buf = Cursor::new(&b"12"[..]);
+        let buf = Cursor::new(&b"12\r"[..]);
         let mut s = buf.lines();
-        assert_eq!(s.next().unwrap().unwrap(), "12".to_string());
+        assert_eq!(s.next().unwrap().unwrap(), "12\r".to_string());
         assert!(s.next().is_none());
 
-        let buf = Cursor::new(&b"12\n\n"[..]);
+        let buf = Cursor::new(&b"12\r\n\n"[..]);
         let mut s = buf.lines();
         assert_eq!(s.next().unwrap().unwrap(), "12".to_string());
         assert_eq!(s.next().unwrap().unwrap(), "".to_string());