From 3da7d918d0d3c443f20d1813772af1ac152b68c7 Mon Sep 17 00:00:00 2001
From: Doug A <douganderson444@gmail.com>
Date: Wed, 5 Jun 2024 13:09:46 -0300
Subject: [PATCH] fix(webrtc-utils): read buffer only if empty message

This PR adds a return of `Poll::Ready(Ok(0))` when the `message` vector is empty or not present.

This missing return was causing the stream not to finish, then to be dropped, causing the request response protocol to fail over WebRTC.

Now that empty or non existent message vectors get returned as `Ok(0)` the stream can be read and request response works now over WebRTC.

Pull-Request: #5439.
---
 Cargo.lock                      |  2 +-
 Cargo.toml                      |  2 +-
 misc/webrtc-utils/CHANGELOG.md  |  5 +++++
 misc/webrtc-utils/Cargo.toml    |  2 +-
 misc/webrtc-utils/src/stream.rs | 10 ++++++++--
 5 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index f526b1983bd..a3e98555eca 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -3500,7 +3500,7 @@ dependencies = [
 
 [[package]]
 name = "libp2p-webrtc-utils"
-version = "0.2.0"
+version = "0.2.1"
 dependencies = [
  "asynchronous-codec",
  "bytes",
diff --git a/Cargo.toml b/Cargo.toml
index eca9c381b5d..8c8c0a70fd8 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -110,7 +110,7 @@ libp2p-tls = { version = "0.4.0", path = "transports/tls" }
 libp2p-uds = { version = "0.40.0", path = "transports/uds" }
 libp2p-upnp = { version = "0.2.2", path = "protocols/upnp" }
 libp2p-webrtc = { version = "0.7.1-alpha", path = "transports/webrtc" }
-libp2p-webrtc-utils = { version = "0.2.0", path = "misc/webrtc-utils" }
+libp2p-webrtc-utils = { version = "0.2.1", path = "misc/webrtc-utils" }
 libp2p-webrtc-websys = { version = "0.3.0-alpha", path = "transports/webrtc-websys" }
 libp2p-websocket = { version = "0.43.0", path = "transports/websocket" }
 libp2p-websocket-websys = { version = "0.3.2", path = "transports/websocket-websys" }
diff --git a/misc/webrtc-utils/CHANGELOG.md b/misc/webrtc-utils/CHANGELOG.md
index 6949113a377..b69bf74bfc8 100644
--- a/misc/webrtc-utils/CHANGELOG.md
+++ b/misc/webrtc-utils/CHANGELOG.md
@@ -1,3 +1,8 @@
+## 0.2.1
+
+- Fix end of stream handling when buffer is empty or not present.
+  See [PR 5439](https://github.com/libp2p/rust-libp2p/pull/5439).
+
 ## 0.2.0
 
 - Update to latest version of `libp2p-noise`.
diff --git a/misc/webrtc-utils/Cargo.toml b/misc/webrtc-utils/Cargo.toml
index f548773b8dd..d870e43781e 100644
--- a/misc/webrtc-utils/Cargo.toml
+++ b/misc/webrtc-utils/Cargo.toml
@@ -7,7 +7,7 @@ license = "MIT"
 name = "libp2p-webrtc-utils"
 repository = "https://github.com/libp2p/rust-libp2p"
 rust-version = { workspace = true }
-version = "0.2.0"
+version = "0.2.1"
 publish = true
 
 [dependencies]
diff --git a/misc/webrtc-utils/src/stream.rs b/misc/webrtc-utils/src/stream.rs
index 0e1496eb640..17f746a92a1 100644
--- a/misc/webrtc-utils/src/stream.rs
+++ b/misc/webrtc-utils/src/stream.rs
@@ -146,8 +146,14 @@ where
                     }
 
                     debug_assert!(read_buffer.is_empty());
-                    if let Some(message) = message {
-                        *read_buffer = message.into();
+                    match message {
+                        Some(msg) if !msg.is_empty() => {
+                            *read_buffer = msg.into();
+                        }
+                        _ => {
+                            tracing::debug!("poll_read buffer is empty, received None");
+                            return Poll::Ready(Ok(0));
+                        }
                     }
                 }
                 None => {