# Buggy code
def _start_server(urlhandler, hostname, port):
    """
    Start an HTTP server thread on a specific port.

    This is a reimplementation of `pydoc._start_server` to handle connection
    errors for 'do_GET'.

    Taken from PyDoc: https://github.com/python/cpython/blob/3.7/Lib/pydoc.py
    """
    import http.server
    import email.message
    import select
    import threading
    import time

    class DocHandler(http.server.BaseHTTPRequestHandler):
        def do_GET(self):
            """Process a request from an HTML browser.

            The URL received is in self.path.
            Get an HTML page from self.urlhandler and send it.
            """
            if self.path.endswith(".css"):
                content_type = "text/css"
            else:
                content_type = "text/html"
            self.send_response(200)
            self.send_header("Content-Type", "%s; charset=UTF-8" % content_type)
            self.end_headers()
            try:
                self.wfile.write(
                    self.urlhandler(self.path, content_type).encode("utf-8")
                )
            except ConnectionAbortedError:
                # Needed to handle error when client closes the connection,
                # for example when the client stops the load of the previously
                # requested page. See spyder-ide/spyder#10755
                pass

        def log_message(self, *args):
            # Don't log messages.
            pass

    class DocServer(http.server.HTTPServer):
        def __init__(self, host, port, callback):
            self.host = host
            self.address = (self.host, port)
            self.callback = callback
            self.base.__init__(self, self.address, self.handler)
            self.quit = False

        def serve_until_quit(self):
            while not self.quit:
                rd, wr, ex = select.select([self.socket.fileno()], [], [], 1)
                if rd:
                    self.handle_request()
            self.server_close()

        def server_activate(self):
            self.base.server_activate(self)
            if self.callback:
                self.callback(self)

    class ServerThread(threading.Thread):
        def __init__(self, urlhandler, host, port):
            self.urlhandler = urlhandler
            self.host = host
            self.port = int(port)
            threading.Thread.__init__(self)
            self.serving = False
            self.error = None

        def run(self):
            """Start the server."""
            try:
                DocServer.base = http.server.HTTPServer
                DocServer.handler = DocHandler
                DocHandler.MessageClass = email.message.Message
                DocHandler.urlhandler = staticmethod(self.urlhandler)
                docsvr = DocServer(self.host, self.port, self.ready)
                self.docserver = docsvr
                docsvr.serve_until_quit()
            except Exception as e:
                self.error = e

        def ready(self, server):
            self.serving = True
            self.host = server.host
            self.port = server.server_port
            self.url = "http://%s:%d/" % (self.host, self.port)

        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

    thread = ServerThread(urlhandler, hostname, port)
    thread.start()
    # Wait until thread.serving is True to make sure we are
    # really up before returning.
    while not thread.error and not thread.serving:
        time.sleep(0.01)
    return thread


# Traceback (BrokenPipeError)
File "/usr/lib64/python3.8/socketserver.py", line 316, in _handle_request_noblock
self.process_request(request, client_address)
File "/usr/lib64/python3.8/socketserver.py", line 347, in process_request
self.finish_request(request, client_address)
File "/usr/lib64/python3.8/socketserver.py", line 360, in finish_request
self.RequestHandlerClass(request, client_address, self)
File "/usr/lib64/python3.8/socketserver.py", line 720, in __init__
self.handle()
File "/usr/lib64/python3.8/http/server.py", line 427, in handle
self.handle_one_request()
File "/usr/lib64/python3.8/http/server.py", line 415, in handle_one_request
method()
File "/usr/lib/python3.8/site-packages/spyder/plugins/onlinehelp/pydoc_patch.py", line 910, in do_GET
self.wfile.write(self.urlhandler(
File "/usr/lib64/python3.8/socketserver.py", line 799, in write
self._sock.sendall(b)
BrokenPipeError: [Errno 32] Broken pipe
----------------------------------------

# Fixed code
def _start_server(urlhandler, hostname, port):
    """
    Start an HTTP server thread on a specific port.

    This is a reimplementation of `pydoc._start_server` to handle connection
    errors for 'do_GET'.

    Taken from PyDoc: https://github.com/python/cpython/blob/3.7/Lib/pydoc.py
    """
    import http.server
    import email.message
    import select
    import threading
    import time

    class DocHandler(http.server.BaseHTTPRequestHandler):
        def do_GET(self):
            """Process a request from an HTML browser.

            The URL received is in self.path.
            Get an HTML page from self.urlhandler and send it.
            """
            if self.path.endswith(".css"):
                content_type = "text/css"
            else:
                content_type = "text/html"
            self.send_response(200)
            self.send_header("Content-Type", "%s; charset=UTF-8" % content_type)
            self.end_headers()
            try:
                self.wfile.write(
                    self.urlhandler(self.path, content_type).encode("utf-8")
                )
            except ConnectionAbortedError:
                # Needed to handle error when client closes the connection,
                # for example when the client stops the load of the previously
                # requested page. See spyder-ide/spyder#10755
                pass
            except BrokenPipeError:
                # Needed to handle permission error when trying to open a port
                # for the web server of the online help.
                # See spyder-ide/spyder#13388
                pass

        def log_message(self, *args):
            # Don't log messages.
            pass

    class DocServer(http.server.HTTPServer):
        def __init__(self, host, port, callback):
            self.host = host
            self.address = (self.host, port)
            self.callback = callback
            self.base.__init__(self, self.address, self.handler)
            self.quit = False

        def serve_until_quit(self):
            while not self.quit:
                rd, wr, ex = select.select([self.socket.fileno()], [], [], 1)
                if rd:
                    self.handle_request()
            self.server_close()

        def server_activate(self):
            self.base.server_activate(self)
            if self.callback:
                self.callback(self)

    class ServerThread(threading.Thread):
        def __init__(self, urlhandler, host, port):
            self.urlhandler = urlhandler
            self.host = host
            self.port = int(port)
            threading.Thread.__init__(self)
            self.serving = False
            self.error = None

        def run(self):
            """Start the server."""
            try:
                DocServer.base = http.server.HTTPServer
                DocServer.handler = DocHandler
                DocHandler.MessageClass = email.message.Message
                DocHandler.urlhandler = staticmethod(self.urlhandler)
                docsvr = DocServer(self.host, self.port, self.ready)
                self.docserver = docsvr
                docsvr.serve_until_quit()
            except Exception as e:
                self.error = e

        def ready(self, server):
            self.serving = True
            self.host = server.host
            self.port = server.server_port
            self.url = "http://%s:%d/" % (self.host, self.port)

        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

    thread = ServerThread(urlhandler, hostname, port)
    thread.start()
    # Wait until thread.serving is True to make sure we are
    # really up before returning.
    while not thread.error and not thread.serving:
        time.sleep(0.01)
    return thread