Address review comments: simplify & comment.

Thanks Eric!

Author: gpshead

Lib/multiprocessing/connection.py

@@ -183,10 +183,7 @@ def close(self):
 
     def _detach(self):
         """Stop managing the underlying file descriptor or handle."""
-        try:
-            return self._handle
-        finally:
-            self._handle = None
+        self._handle = None
 
     def send_bytes(self, buf, offset=0, size=None):
         """Send the bytes data from a bytes-like object"""

Lib/multiprocessing/forkserver.py

@@ -97,17 +97,19 @@ def connect_to_new_process(self, fds):
                       resource_tracker.getfd()]
             allfds += fds
             try:
-                if self._forkserver_authkey:
-                    client.setblocking(True)
-                    wrapped_client = connection.Connection(client.fileno())
-                    try:
-                        connection.answer_challenge(
-                                wrapped_client, self._forkserver_authkey)
-                        connection.deliver_challenge(
-                                wrapped_client, self._forkserver_authkey)
-                    finally:
-                        wrapped_client._detach()
-                        del wrapped_client
+                assert self._forkserver_authkey
+                client.setblocking(True)
+                wrapped_client = connection.Connection(client.fileno())
+                # The other side of this exchange happens in the child as
+                # implemented in main().
+                try:
+                    connection.answer_challenge(
+                            wrapped_client, self._forkserver_authkey)
+                    connection.deliver_challenge(
+                            wrapped_client, self._forkserver_authkey)
+                finally:
+                    wrapped_client._detach()
+                    del wrapped_client
                 reduction.sendfds(client, allfds)
                 return parent_r, parent_w
             except:
@@ -296,6 +298,8 @@ def sigchld_handler(*_unused):
                         try:
                             if authkey:
                                 wrapped_s = connection.Connection(s.fileno())
+                                # The other side of this exchange happens in
+                                # in connect_to_new_process().
                                 try:
                                     connection.deliver_challenge(
                                             wrapped_s, authkey)

Lib/test/_test_multiprocessing.py

@@ -914,8 +914,8 @@ def test_forkserver_auth_is_enabled(self):
         addr = forkserver._forkserver_address
         self.assertTrue(addr)
 
-        # First, demonstrate that a raw auth handshake as Client makes
-        # does not raise an error.
+        # Demonstrate that a raw auth handshake, as Client performs, does not
+        # raise an error.
         client = multiprocessing.connection.Client(addr, authkey=authkey)
         client.close()