From 11a64a18342865b166d2da703a06deb447f834c1 Mon Sep 17 00:00:00 2001
From: Zachary S <zasample18+github@gmail.com>
Date: Fri, 1 Sep 2023 20:20:29 -0500
Subject: [PATCH] don't panic in BorrowedCursor::write

---
 library/std/src/io/readbuf.rs | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/library/std/src/io/readbuf.rs b/library/std/src/io/readbuf.rs
index 034ddd8df9a..95044de2a09 100644
--- a/library/std/src/io/readbuf.rs
+++ b/library/std/src/io/readbuf.rs
@@ -306,8 +306,9 @@ pub fn append(&mut self, buf: &[u8]) {
 
 impl<'a> Write for BorrowedCursor<'a> {
     fn write(&mut self, buf: &[u8]) -> Result<usize> {
-        self.append(buf);
-        Ok(buf.len())
+        let amt = cmp::min(buf.len(), self.capacity());
+        self.append(&buf[..amt]);
+        Ok(amt)
     }
 
     #[inline]