Do not use SO_REUSEADDR et all when listening on ephemeral ports (#1064)

src/debugpy/common/sockets.py

@@ -21,6 +21,17 @@ def create_server(host, port=0, backlog=socket.SOMAXCONN, timeout=None):
 
     try:
         server = _new_sock()
+        if port != 0:
+            # If binding to a specific port, make sure that the user doesn't have
+            # to wait until the OS times out the socket to be able to use that port
+            # again.if the server or the adapter crash or are force-killed.
+            if sys.platform == "win32":
+                server.setsockopt(socket.SOL_SOCKET, socket.SO_EXCLUSIVEADDRUSE, 1)
+            else:
+                try:
+                    server.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
+                except (AttributeError, OSError):
+                    pass  # Not available everywhere
         server.bind((host, port))
         if timeout is not None:
             server.settimeout(timeout)
@@ -38,13 +49,6 @@ def create_client():
 
 def _new_sock():
     sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM, socket.IPPROTO_TCP)
-    if sys.platform == "win32":
-        sock.setsockopt(socket.SOL_SOCKET, socket.SO_EXCLUSIVEADDRUSE, 1)
-    else:
-        try:
-            sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
-        except (AttributeError, OSError):
-            pass  # Not available everywhere
 
     # Set TCP keepalive on an open socket.
     # It activates after 1 second (TCP_KEEPIDLE,) of idleness,