From 18d0affc015cd1be02cc9b227c4d89007dd8c816 Mon Sep 17 00:00:00 2001 From: Shivam Sandbhor Date: Mon, 5 Aug 2019 16:53:35 +0530 Subject: [PATCH] Update reactor.py, updated 'if' sequencing , possibly eliminating a bug if portrange=None This should be the proper ordering.This is the explanation. If 'not portrange' is True ,it is guaranteed that `not hasattr(portrange, '__iter__')` is also True the converse of this is not always true.(for example, consider portrange=None, for such case we were executing the logic for `not hasattr(portrange, '__iter__')` . ).Such case is eliminated by this PR. --- scrapy/utils/reactor.py | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/scrapy/utils/reactor.py b/scrapy/utils/reactor.py index 83186a372..eda7867e3 100644 --- a/scrapy/utils/reactor.py +++ b/scrapy/utils/reactor.py @@ -3,10 +3,10 @@ from twisted.internet import reactor, error def listen_tcp(portrange, host, factory): """Like reactor.listenTCP but tries different ports in a range.""" assert len(portrange) <= 2, "invalid portrange: %s" % portrange - if not hasattr(portrange, '__iter__'): - return reactor.listenTCP(portrange, factory, interface=host) if not portrange: return reactor.listenTCP(0, factory, interface=host) + if not hasattr(portrange, '__iter__'): + return reactor.listenTCP(portrange, factory, interface=host) if len(portrange) == 1: return reactor.listenTCP(portrange[0], factory, interface=host) for x in range(portrange[0], portrange[1]+1):