From 467a0816651d3c3de93ef3756f5f6b63fa801364 Mon Sep 17 00:00:00 2001
From: nightcityblade <nightcityblade@gmail.com>
Date: Sun, 16 Aug 2026 11:26:32 +0800
Subject: [PATCH] Set TCP_NODELAY on pydevd client connections

---
 .../pydevd/_pydevd_bundle/pydevd_comm.py         |  4 ++++
 .../pydevd/tests_python/test_pydevd_comm.py      | 16 ++++++++++++++++
 2 files changed, 20 insertions(+)
 create mode 100644 src/debugpy/_vendored/pydevd/tests_python/test_pydevd_comm.py

diff --git a/src/debugpy/_vendored/pydevd/_pydevd_bundle/pydevd_comm.py b/src/debugpy/_vendored/pydevd/_pydevd_bundle/pydevd_comm.py
index b935320c..22cd190b 100644
--- a/src/debugpy/_vendored/pydevd/_pydevd_bundle/pydevd_comm.py
+++ b/src/debugpy/_vendored/pydevd/_pydevd_bundle/pydevd_comm.py
@@ -525,6 +525,10 @@ def start_client(host, port):
         s.setsockopt(socket_module.IPPROTO_TCP, socket_module.TCP_KEEPCNT, 5)
     except (AttributeError, OSError):
         pass  # May not be available everywhere.
+    try:
+        s.setsockopt(socket_module.IPPROTO_TCP, socket_module.TCP_NODELAY, 1)
+    except (AttributeError, OSError):
+        pass  # May not be available everywhere.
 
     try:
         # 10 seconds default timeout
diff --git a/src/debugpy/_vendored/pydevd/tests_python/test_pydevd_comm.py b/src/debugpy/_vendored/pydevd/tests_python/test_pydevd_comm.py
new file mode 100644
index 00000000..68742f98
--- /dev/null
+++ b/src/debugpy/_vendored/pydevd/tests_python/test_pydevd_comm.py
@@ -0,0 +1,16 @@
+from unittest import mock
+
+from _pydevd_bundle import pydevd_comm
+
+
+def test_start_client_sets_tcp_nodelay(monkeypatch):
+    sock = mock.Mock()
+    monkeypatch.setattr(pydevd_comm, "socket", lambda *_: sock)
+    monkeypatch.setattr(pydevd_comm.socket_module, "getaddrinfo", lambda *_: [])
+
+    assert pydevd_comm.start_client("localhost", 5678) is sock
+    sock.setsockopt.assert_any_call(
+        pydevd_comm.socket_module.IPPROTO_TCP,
+        pydevd_comm.socket_module.TCP_NODELAY,
+        1,
+    )