🚑 Merge remote-tracking branch 'cameronbrunner/issue-358'

This change makes sure that only valid connections are processed.

The `_from_server_socket` routine may return a `None` when the attempt
to establish the connection goes wrong. Like if a client tries to
speak plain text HTTP to HTTPS socket. Earlier, this was causing
`None` to be forwarded to workers to processes making them to exit.
Eventually, there would be no workers left in the pool and the server
would reset any attempts to establish new connections.

Ref #358

CHANGES.rst

@@ -1,3 +1,11 @@
+.. scm-version-title:: v8.5.2
+
+- :issue:`358` via :pr:`359`: Fixed a regression from
+  :pr:`199` that made the worker threads exit on invalid
+  connection attempts and could make the whole server
+  unresponsive once there was no workers left.
+  -- by :user:`cameronbrunner`.
+
 .. scm-version-title:: v8.5.1
 
 - :cp-issue:`1873` via :pr:`340`: Resurrected an

cheroot/connections.py

@@ -216,7 +216,8 @@ def _run(self, expiration_interval):
                 if conn is self.server:
                     # New connection
                     new_conn = self._from_server_socket(self.server.socket)
-                    self.server.process_conn(new_conn)
+                    if new_conn is not None:
+                        self.server.process_conn(new_conn)
                 else:
                     # unregister connection from the selector until the server
                     # has read from it and returned it via put()