Fixes #425 Remove UNIX socket from FS before binding.

Author: socketpair

asyncio/unix_events.py

@@ -258,6 +258,17 @@ def create_unix_server(self, protocol_factory, path=None, *,
 
             sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
 
+            # Check for abstract socket. `str` and `bytes` paths are supported.
+            if path[0] not in (0, '\x00'):
+                try:
+                    if stat.S_ISSOCK(os.stat(path).st_mode):
+                        os.remove(path)
+                except FileNotFoundError:
+                    pass
+                except OSError as err:
+                    # Directory may have permissions only to create socket.
+                    logger.error('Unable to check or remove stale UNIX socket %r: %r', path, err)
+
             try:
                 sock.bind(path)
             except OSError as exc:

tests/test_unix_events.py

@@ -241,11 +241,11 @@ def test_create_unix_server_existing_path_sock(self):
         with test_utils.unix_socket_path() as path:
             sock = socket.socket(socket.AF_UNIX)
             sock.bind(path)
-            with sock:
-                coro = self.loop.create_unix_server(lambda: None, path)
-                with self.assertRaisesRegex(OSError,
-                                            'Address.*is already in use'):
-                    self.loop.run_until_complete(coro)
+            sock.listen(1)
+            sock.close()
+
+            coro = self.loop.create_unix_server(lambda: None, path)
+            self.loop.run_until_complete(coro)
 
     def test_create_unix_server_existing_path_nonsock(self):
         with tempfile.NamedTemporaryFile() as file: