From 869c3b46ac9a117c2d03902ff9e7f71bccf8ea6f Mon Sep 17 00:00:00 2001
From: Brad Dunbar <dunbarb2@gmail.com>
Date: Sat, 2 Mar 2024 09:43:49 -0500
Subject: [PATCH 1/3] Remove redundant reserve call.

1. put_u8 calls put_slice
2. BytesMut::put_slice calls BytesMut::extend_from_slice
3. BytesMut::extend_from_slice immediately calls reserve
---
 src/bytes_mut.rs | 1 -
 1 file changed, 1 deletion(-)

diff --git a/src/bytes_mut.rs b/src/bytes_mut.rs
index 220bdb005..aec83f198 100644
--- a/src/bytes_mut.rs
+++ b/src/bytes_mut.rs
@@ -1285,7 +1285,6 @@ impl Extend<u8> for BytesMut {
         // 1. If self.kind() == KIND_VEC, use Vec::extend
         // 2. Make `reserve` inline-able
         for b in iter {
-            self.reserve(1);
             self.put_u8(b);
         }
     }

From 0211037ad7e05b66580d4328b55c841a632f5911 Mon Sep 17 00:00:00 2001
From: Brad Dunbar <dunbarb2@gmail.com>
Date: Sat, 2 Mar 2024 09:47:30 -0500
Subject: [PATCH 2/3] remove inline-able todo

reserve is already inline-able
---
 src/bytes_mut.rs | 1 -
 1 file changed, 1 deletion(-)

diff --git a/src/bytes_mut.rs b/src/bytes_mut.rs
index aec83f198..2568975de 100644
--- a/src/bytes_mut.rs
+++ b/src/bytes_mut.rs
@@ -1283,7 +1283,6 @@ impl Extend<u8> for BytesMut {
 
         // TODO: optimize
         // 1. If self.kind() == KIND_VEC, use Vec::extend
-        // 2. Make `reserve` inline-able
         for b in iter {
             self.put_u8(b);
         }

From 76dae7b880c52384d6a3edb364f1375b45a9274f Mon Sep 17 00:00:00 2001
From: Brad Dunbar <dunbarb2@gmail.com>
Date: Sun, 3 Mar 2024 17:43:41 -0500
Subject: [PATCH 3/3] add a test for extending past lower limit

For https://github.com/tokio-rs/bytes/pull/674#pullrequestreview-1913035700
---
 tests/test_bytes.rs | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/tests/test_bytes.rs b/tests/test_bytes.rs
index 76adfdbf4..e3820d76e 100644
--- a/tests/test_bytes.rs
+++ b/tests/test_bytes.rs
@@ -598,6 +598,28 @@ fn extend_mut_from_bytes() {
     assert_eq!(*bytes, LONG[..]);
 }
 
+#[test]
+fn extend_past_lower_limit_of_size_hint() {
+    // See https://github.com/tokio-rs/bytes/pull/674#pullrequestreview-1913035700
+    struct Iter<I>(I);
+
+    impl<I: Iterator<Item = u8>> Iterator for Iter<I> {
+        type Item = u8;
+
+        fn next(&mut self) -> Option<Self::Item> {
+            self.0.next()
+        }
+
+        fn size_hint(&self) -> (usize, Option<usize>) {
+            (5, None)
+        }
+    }
+
+    let mut bytes = BytesMut::with_capacity(5);
+    bytes.extend(Iter(std::iter::repeat(0).take(10)));
+    assert_eq!(bytes.len(), 10);
+}
+
 #[test]
 fn extend_mut_without_size_hint() {
     let mut bytes = BytesMut::with_capacity(0);