From eb7ae10dec88a71f8ef29ce914529040bbd43374 Mon Sep 17 00:00:00 2001
From: pluveto <zijing.zhang@proton.me>
Date: Tue, 26 Nov 2024 22:13:07 +0800
Subject: [PATCH] Add assertion in `produce` method to check buffer capacity in
 implementations for `BufWriter`

---
 src/futures/write/buf_writer.rs | 7 ++++++-
 src/tokio/write/buf_writer.rs   | 7 ++++++-
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/src/futures/write/buf_writer.rs b/src/futures/write/buf_writer.rs
index f3948c6..895ccc2 100644
--- a/src/futures/write/buf_writer.rs
+++ b/src/futures/write/buf_writer.rs
@@ -193,7 +193,12 @@ impl<W: AsyncWrite> AsyncBufWrite for BufWriter<W> {
     }
 
     fn produce(self: Pin<&mut Self>, amt: usize) {
-        *self.project().buffered += amt;
+        let this = self.project();
+        assert!(
+            *this.buffered + amt <= this.buf.len(),
+            "produce called with amt exceeding buffer capacity"
+        );
+        *this.buffered += amt;
     }
 }
 
diff --git a/src/tokio/write/buf_writer.rs b/src/tokio/write/buf_writer.rs
index 620ed85..40e87f1 100644
--- a/src/tokio/write/buf_writer.rs
+++ b/src/tokio/write/buf_writer.rs
@@ -193,7 +193,12 @@ impl<W: AsyncWrite> AsyncBufWrite for BufWriter<W> {
     }
 
     fn produce(self: Pin<&mut Self>, amt: usize) {
-        *self.project().buffered += amt;
+        let this = self.project();
+        assert!(
+            *this.buffered + amt <= this.buf.len(),
+            "produce called with amt exceeding buffer capacity"
+        );
+        *this.buffered += amt;
     }
 }