xml.dom.minidom.Node.removeChild() doesn't remove

[mkempka]

BPO	1157901
Files	dombug.py: code to demonstrate the bug errorintroducer.xml: the xml file that produces the error errorfree.xml: the (almost) same contents that don't produce the error

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GitHub fields:

assignee = None
closed_at = <Date 2005-05-20.21:44:01.000>
created_at = <Date 2005-03-06.21:17:08.000>
labels = ['expert-XML', 'invalid']
title = "xml.dom.minidom.Node.removeChild() doesn't remove"
updated_at = <Date 2005-05-20.21:44:01.000>
user = 'https://bugs.python.org/mkempka'

bugs.python.org fields:

activity = <Date 2005-05-20.21:44:01.000>
actor = 'mkempka'
assignee = 'none'
closed = True
closed_date = None
closer = None
components = ['XML']
creation = <Date 2005-03-06.21:17:08.000>
creator = 'mkempka'
dependencies = []
files = ['1620', '1621', '1622']
hgrepos = []
issue_num = 1157901
keywords = []
message_count = 4.0
messages = ['24480', '24481', '24482', '24483']
nosy_count = 2.0
nosy_names = ['mkempka', 'bobince']
pr_nums = []
priority = 'normal'
resolution = 'not a bug'
stage = None
status = 'closed'
superseder = None
type = None
url = 'https://bugs.python.org/issue1157901'
versions = ['Python 2.3']

[mkempka]

There seems to be a constellation where
xml.dom.minidom.Node.removeChild() doesn't remove
childs properly.

I found this bug in 2.3.4 and it is still in:

Python 2.3.5 (#2, Feb 9 2005, 00:38:15)
[GCC 3.3.5 (Debian 1:3.3.5-8)] on linux2

I attached 3 files, the dombug.py demonstrates the
problem:

First, I iterate over all children of a specific
element, check their tag name and remove them using
removeChild() and then child.unlink().
After the elements are removed I iterate again, do the
same check for a tag and find there are still elements
in there. That is, there are still elements in there
when I parse the file errorintroducer.xml. When I parse
the file errorfree.xml the elements are all removed.

The difference between the xml files is the carriage
return after each closing tag.

Since to my knowledge both xml files are well-formed I
would expect in both cases that all elements are removed.

[mkempka]

Logged In: YES
user_id=736381

so.. this form posts the error report with uploading
files...interesting...

Anyway, the output I get when running the program with
errorintroducer.xml is:

python dombug.py
found element 1
.. removed
found element 3
.. removed
found element 5
.. removed
-----------everything removed from timerList[0]---------------
found Element 2
found Element 4
found Element 6

imho it should be, as it is with errorfree.xml:

found element 1
.. removed
found element 2
.. removed
found element 3
.. removed
found element 4
.. removed
found element 5
.. removed
found element 6
.. removed
-----------everything removed from timerList[0]---------------

[bobince]

Logged In: YES
user_id=311085

Bug should be marked INVALID.

childNodes lists are 'live'. You are iterating over a list
you are destroying at the same time. The code is equivalent
to the more obviously broken:

  foo= [1, 2, 3, 4]
  i= 0
  while i<len(foo):
    del foo[i]
    i+= 1
  foo
  >>> [2, 4]

The 'working' example only works because it has extra
whitespace nodes in, so when you delete child number i, the
child i+1 that is skipped over is a Text node containing
only whitespace.

BTW, there's a separate bug tracker for the PyXML project
from which minidom is taken. You may get better results by
submitting there (and discussing on the XML-SIG list).

[mkempka]

Logged In: YES
user_id=736381

well then, invalid.