From ee94bdb0598f9bc47d6a49e58fffc97aa617be96 Mon Sep 17 00:00:00 2001
From: "Jason R. Coombs" <jaraco@jaraco.com>
Date: Sun, 5 Jan 2020 22:32:19 -0500
Subject: bpo-38907: In http.server script, restore binding to IPv4 on Windows.
 (GH-17851)

---
 Lib/http/server.py                                         | 14 +++++++++++++-
 .../next/Library/2020-01-06-02-14-38.bpo-38907.F1RkCR.rst  |  1 +
 2 files changed, 14 insertions(+), 1 deletion(-)
 create mode 100644 Misc/NEWS.d/next/Library/2020-01-06-02-14-38.bpo-38907.F1RkCR.rst

diff --git a/Lib/http/server.py b/Lib/http/server.py
index 47a4fcf..b9a2717 100644
--- a/Lib/http/server.py
+++ b/Lib/http/server.py
@@ -1282,4 +1282,16 @@ if __name__ == '__main__':
     else:
         handler_class = partial(SimpleHTTPRequestHandler,
                                 directory=args.directory)
-    test(HandlerClass=handler_class, port=args.port, bind=args.bind)
+
+    # ensure dual-stack is not disabled; ref #38907
+    class DualStackServer(ThreadingHTTPServer):
+        def server_bind(self):
+            self.socket.setsockopt(socket.IPPROTO_IPV6, socket.IPV6_V6ONLY, 0)
+            return super().server_bind()
+
+    test(
+        HandlerClass=handler_class,
+        ServerClass=DualStackServer,
+        port=args.port,
+        bind=args.bind,
+    )
diff --git a/Misc/NEWS.d/next/Library/2020-01-06-02-14-38.bpo-38907.F1RkCR.rst b/Misc/NEWS.d/next/Library/2020-01-06-02-14-38.bpo-38907.F1RkCR.rst
new file mode 100644
index 0000000..a6e79f7
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2020-01-06-02-14-38.bpo-38907.F1RkCR.rst
@@ -0,0 +1 @@
+In http.server script, restore binding to IPv4 on Windows.
\ No newline at end of file
-- 
cgit v0.12