From 57f279d91b7deea8958b7718cfc720974bd2a11f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Beno=C3=AEt=20du=20Garreau?= <bdgdlm@outlook.com>
Date: Wed, 22 May 2024 11:41:19 +0200
Subject: [PATCH] Fix `io::BufReader` uses of `read_buf`

---
 std/src/io/buffered/bufreader.rs        | 2 +-
 std/src/io/buffered/bufreader/buffer.rs | 4 +++-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/std/src/io/buffered/bufreader.rs b/std/src/io/buffered/bufreader.rs
index e51dde994de45..438df70505b20 100644
--- a/std/src/io/buffered/bufreader.rs
+++ b/std/src/io/buffered/bufreader.rs
@@ -349,7 +349,7 @@ impl<R: ?Sized + Read> Read for BufReader<R> {
         let prev = cursor.written();
 
         let mut rem = self.fill_buf()?;
-        rem.read_buf(cursor.reborrow())?;
+        rem.read_buf(cursor.reborrow())?; // actually never fails
 
         self.consume(cursor.written() - prev); //slice impl of read_buf known to never unfill buf
 
diff --git a/std/src/io/buffered/bufreader/buffer.rs b/std/src/io/buffered/bufreader/buffer.rs
index 1bf84d8bef312..68b024bb98aac 100644
--- a/std/src/io/buffered/bufreader/buffer.rs
+++ b/std/src/io/buffered/bufreader/buffer.rs
@@ -133,11 +133,13 @@ impl Buffer {
                 buf.set_init(self.initialized);
             }
 
-            reader.read_buf(buf.unfilled())?;
+            let result = reader.read_buf(buf.unfilled());
 
             self.pos = 0;
             self.filled = buf.len();
             self.initialized = buf.init_len();
+
+            result?;
         }
         Ok(self.buffer())
     }