From 333911a4b8d16b17357944a2b8af657a66f165af Mon Sep 17 00:00:00 2001
From: Justin Karneges <jkarneges@fastly.com>
Date: Thu, 18 Jun 2026 09:13:24 -0700
Subject: [PATCH] connmgr: remove unused overflow feature in server responses

---
 src/connmgr/connection.rs | 19 +++----------------
 src/core/http1/server.rs  |  4 ++--
 2 files changed, 5 insertions(+), 18 deletions(-)

diff --git a/src/connmgr/connection.rs b/src/connmgr/connection.rs
index 3283375d..be272180 100644
--- a/src/connmgr/connection.rs
+++ b/src/connmgr/connection.rs
@@ -3657,14 +3657,10 @@ where
                 };
 
                 // First call can't fail
-                let (size, overflowed) = prepare_body
+                let size = prepare_body
                     .prepare(rdata.body, true)
                     .expect("infallible prepare call failed");
 
-                if overflowed > 0 {
-                    debug!("server-conn {}: overflowing {} bytes", id, overflowed);
-                }
-
                 // We confirmed above that the data will fit in the buffer
                 assert!(size == rdata.body.len());
 
@@ -3780,14 +3776,10 @@ where
     };
 
     // First call can't fail
-    let (size, overflowed) = prepare_body
+    let size = prepare_body
         .prepare(rdata.body, !rdata.more)
         .expect("infallible prepare call failed");
 
-    if overflowed > 0 {
-        debug!("server-conn {}: overflowing {} bytes", id, overflowed);
-    }
-
     // We confirmed above that the data will fit in the buffer
     assert!(size == rdata.body.len());
 
@@ -3930,12 +3922,7 @@ where
 
                     match &zresp.get().ptype {
                         zhttppacket::ResponsePacket::Data(rdata) => {
-                            let (size, overflowed) =
-                                prepare_body.prepare(rdata.body, !rdata.more)?;
-
-                            if overflowed > 0 {
-                                debug!("server-conn {}: overflowing {} bytes", id, overflowed);
-                            }
+                            let size = prepare_body.prepare(rdata.body, !rdata.more)?;
 
                             if size < rdata.body.len() {
                                 return Err(Error::BufferExceeded);
diff --git a/src/core/http1/server.rs b/src/core/http1/server.rs
index 17aae4c0..2ceb86bd 100644
--- a/src/core/http1/server.rs
+++ b/src/core/http1/server.rs
@@ -564,7 +564,7 @@ pub struct ResponsePrepareBody<'a, 'b, R: AsyncRead, W: AsyncWrite> {
 
 impl<R: AsyncRead, W: AsyncWrite> ResponsePrepareBody<'_, '_, R, W> {
     // Only returns an error on invalid input
-    pub fn prepare(&mut self, src: &[u8], end: bool) -> Result<(usize, usize), Error> {
+    pub fn prepare(&mut self, src: &[u8], end: bool) -> Result<usize, Error> {
         let state = self.state.borrow();
         let state = state.as_ref().unwrap();
 
@@ -589,7 +589,7 @@ impl<R: AsyncRead, W: AsyncWrite> ResponsePrepareBody<'_, '_, R, W> {
             state.end.set(true);
         }
 
-        Ok((size, 0))
+        Ok(size)
     }
 }