Assertion error when cleaning

[Jason Baker]

Python : (2, 6, 6, 'final', 0)
lxml.etree : (2, 3, -99, 0)
libxml used : (2, 6, 26)
libxml compiled : (2, 6, 26)
libxslt used : (1, 1, 17)
libxslt compiled : (1, 1, 17)

This is an error that's being sent out by our production process. Thus far, I haven't been able to reproduce it:

Traceback (most recent call last):
  File "/home/csar/current/apture/main/workers/base.py", line 144, in _wrappedMethod
    return method(logger, queueName, decoded)
  File "/home/csar/current/apture/main/workers/magiclinker.py", line 115, in execute
    cleaner.clean_html(html)
  File "/usr/local/lib/python2.6/site-packages/lxml/html/clean.py", line 488, in clean_html
    self(doc)
  File "/usr/local/lib/python2.6/site-packages/lxml/html/clean.py", line 390, in __call__
    el.drop_tag()
  File "/usr/local/lib/python2.6/site-packages/lxml/html/__init__.py", line 191, in drop_tag
    assert parent is not None
AssertionError

If nothing else, this belongs in the "needs a better error message" category.

[Johannes (johtso)]

I seem to be experiencing this bug.

Is this code reproducing the same problem?

[Jason Baker (jbaker)]

Here's a simple page that causes this error: http://nepis.epa.gov/Exe/ZyNET.exe/20017XVV.TXT

Obviously, this isn't valid HTML (and neither is the one that Johannes posted). I can reproduce this at the interactive prompt:

>>> from lxml.html import fromstring
>>> h = fromstring('<ZyNETERROR>Parsing form data failed.</ZyNETERROR>')
>>> h
<Element zyneterror at 0xb71caaac>
>>> from lxml.html import clean
>>> c = clean.Cleaner()
>>> c.clean_html(h)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python2.6/dist-packages/lxml/html/clean.py", line 488, in clean_html
    self(doc)
  File "/usr/lib/python2.6/dist-packages/lxml/html/clean.py", line 390, in __call__
    el.drop_tag()
  File "/usr/lib/python2.6/dist-packages/lxml/html/__init__.py", line 191, in drop_tag
    assert parent is not None
AssertionError

So it definitely seems that this is a case of needing better error messages.

[scoder (scoder)]

Thanks for the report and the test case. Here's a fix:

https://github.com/lxml/lxml/commit/c531d3326cd1e6fd888299518d49acad5fd3b627

[scoder (scoder)]

Fixed in lxml 2.3.1.