我要评论
商业价值,内江师范学院录取查询,诸神学徒txt下载
bug触发时的完整报错内容（本地无关路径用已经用 **** 隐去）：
**************\lib\site-packages\bs4\builder\_htmlparser.py:78: userwarning: unknown status keyword 'end ' in marked section
warnings.warn(msg)
traceback (most recent call last):
file "**************/test.py", line 5, in <module>
bs = beautifulsoup(html, 'html.parser')
file "**************\lib\site-packages\bs4\__init__.py", line 281, in __init__
self._feed()
file "**************\lib\site-packages\bs4\__init__.py", line 342, in _feed
self.builder.feed(self.markup)
file "**************\lib\site-packages\bs4\builder\_htmlparser.py", line 247, in feed
parser.feed(markup)
file "d:\program files\python37\lib\html\parser.py", line 111, in feed
self.goahead(0)
file "d:\program files\python37\lib\html\parser.py", line 179, in goahead
k = self.parse_html_declaration(i)
file "d:\program files\python37\lib\html\parser.py", line 264, in parse_html_declaration
return self.parse_marked_section(i)
file "d:\program files\python37\lib\_markupbase.py", line 160, in parse_marked_section
if not match:
unboundlocalerror: local variable 'match' referenced before assignment
在解析html时，标签开始部分使用形如 <!-[if ie eq 9]> 的浏览器判断标识符，结束时结束标签<![end if]->(正确的开始和结束标签应该为<!--[if ie 9]> 和 <![endif]-->)无法正常匹配关闭即可触发。
触发bug的示例代码如下：
from bs4 import beautifulsoup
html = """
<!-[if ie eq 9]>
<a href="https://www.shwww.net/">https://www.shwww.net/</a>
<![end if]->
"""
bs = beautifulsoup(html, 'html.parser')
在 python 3.7.0 版本中，触发bug部分的代码存在于 \lib\_markupbase.py 中的 146 行的 parse_marked_section 方法，该方法代码如下：
https://github.com/python/cpython/blob/bb9ddee3d4e293f0717f8c167afdf5749ebf843d/lib/_markupbase.py#l160
def parse_marked_section(self, i, report=1):
rawdata= self.rawdata
assert rawdata[i:i+3] == '<![', "unexpected call to parse_marked_section()"
sectname, j = self._scan_name( i+3, i )
if j < 0:
return j
if sectname in {"temp", "cdata", "ignore", "include", "rcdata"}:
# look for standard ]]> ending
match= _markedsectionclose.search(rawdata, i+3)
elif sectname in {"if", "else", "endif"}:
# look for ms office ]> ending
match= _msmarkedsectionclose.search(rawdata, i+3)
else:
self.error('unknown status keyword %r in marked section' % rawdata[i+3:j])
if not match:
return -1
if report:
j = match.start(0)
self.unknown_decl(rawdata[i+3: j])
return match.end(0)
由于错误的html代码未正确关闭，使得流程判断既没有进入 if sectname in {"temp", "cdata", "ignore", "include", "rcdata"}:
和 elif sectname in {"if", "else", "endif"}: ，而是报出一个错误 userwarning: unknown status keyword 'end ' in marked section warnings.warn(msg) 后执行到 if not match ，而此时 match 未申明，故而触发错误。
此bug存在于多个python版本中，修复方法，在 if sectname in {"temp", "cdata", "ignore", "include", "rcdata"}: 之前预定义一个match变量即可：
https://github.com/python/cpython/blob/bb9ddee3d4e293f0717f8c167afdf5749ebf843d/lib/_markupbase.py#l152
def parse_marked_section(self, i, report=1):
rawdata= self.rawdata
assert rawdata[i:i+3] == '<![', "unexpected call to parse_marked_section()"
sectname, j = self._scan_name( i+3, i )
if j < 0:
return j
match = none
if sectname in {"temp", "cdata", "ignore", "include", "rcdata"}:
# look for standard ]]> ending
match= _markedsectionclose.search(rawdata, i+3)
elif sectname in {"if", "else", "endif"}:
# look for ms office ]> ending
match= _msmarkedsectionclose.search(rawdata, i+3)
else:
self.error('unknown status keyword %r in marked section' % rawdata[i+3:j])
if not match:
return -1
if report:
j = match.start(0)
self.unknown_decl(rawdata[i+3: j])
return match.end(0)
如对本文有疑问，请在下面进行留言讨论，广大热心网友会与你互动！！ 点击进行留言回复
python求numpy中array按列非零元素的平均值案例
网友评论