python
diff --git a/‎Lib/pydoc.py‎
Lines changed: 4 additions & 0 deletions b/‎Lib/pydoc.py‎
Lines changed: 4 additions & 0 deletions
diff --git a/‎Misc/NEWS.d/next/Library/2017-08-21-12-31-53.bpo-31238.Gg0LRH.rst‎
Lines changed: 3 additions & 0 deletions b/‎Misc/NEWS.d/next/Library/2017-08-21-12-31-53.bpo-31238.Gg0LRH.rst‎
Lines changed: 3 additions & 0 deletions
@@ -2297,6 +2297,10 @@ def ready(self, server):
         def stop(self):
             """Stop the server and this thread nicely"""
             self.docserver.quit = True
+            self.join()
+            # explicitly break a reference cycle: DocServer.callback
+            # has indirectly a reference to ServerThread.
+            self.docserver = None
             self.serving = False
             self.url = None
 
 
@@ -0,0 +1,3 @@
+pydoc: the stop() method of the private ServerThread class now waits until
+DocServer.serve_until_quit() completes and then explicitly sets its
+docserver attribute to None to break a reference cycle.
Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,3 @@`
	`1`	`+pydoc: the stop() method of the private ServerThread class now waits until`
	`2`	`+DocServer.serve_until_quit() completes and then explicitly sets its`
	`3`	`+docserver attribute to None to break a reference cycle.`