xml.sax.saxutils.escape does not escapes \x00

[animus]

BPO	13648
Nosy	@loewis

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2012-06-20.19:56:12.020>
created_at = <Date 2011-12-22.14:49:17.023>
labels = ['expert-XML', 'type-bug']
title = 'xml.sax.saxutils.escape does not escapes \\x00'
updated_at = <Date 2012-06-20.19:56:12.019>
user = 'https://bugs.python.org/animus'

bugs.python.org fields:

activity = <Date 2012-06-20.19:56:12.019>
actor = 'loewis'
assignee = 'none'
closed = True
closed_date = <Date 2012-06-20.19:56:12.020>
closer = 'loewis'
components = ['XML']
creation = <Date 2011-12-22.14:49:17.023>
creator = 'animus'
dependencies = []
files = []
hgrepos = []
issue_num = 13648
keywords = []
message_count = 6.0
messages = ['150096', '150097', '150136', '163291', '163292', '163294']
nosy_count = 2.0
nosy_names = ['loewis', 'animus']
pr_nums = []
priority = 'normal'
resolution = 'wont fix'
stage = None
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue13648'
versions = ['Python 2.6', 'Python 3.1', 'Python 2.7', 'Python 3.2']

[animus]

function xml.sax.saxutils.escape('\x00qweqwe<') returns '\x00qweqwe<'

\x00 did not escaped to �

is this is a correct behavior?

this is influences tools like xmpppy, which sends \x00 not encoded and leads to xmpp error.

[animus]

sorry, xmpppy uses it's own escape method, but anyway... :)

[loewis]

This is correct behavior. \x00 is not supported in XML: not in raw form, and not in escaped form. To transmit binary data in XML, use base64.

[animus]

This is correct behavior. \x00 is not supported in XML:
not in raw form, and not in escaped form

last sentence in forth paragraph of section 1.3 in XML 1.1 specification says following:
======
Due to potential problems with APIs,
#x0 is still forbidden both directly and as a character reference.
======

And, second sentence in paragraph 2 in subsection 'Validity constraint: Notation Declared' of section 4.2.2 says following:
======
The characters to be escaped are the control characters #x0 to #x1F and #x7F (most of which cannot appear in XML), space #x20, the delimiters '<' #x3C, '>' #x3E and '"' #x22, the unwise characters '{' #x7B, '}' #x7D, '|' #x7C, '\' #x5C, '^' #x5E and '`' #x60, as well as all characters above #x7F.
======

(xml 1.1) http://www.w3.org/TR/2006/REC-xml11-20060816/
(xml 1.0) http://www.w3.org/TR/2008/REC-xml-20081126/

[animus]

What am I trying to say is: if those characters are forbidden, then maybe they need to be escaped rather than ignored?

[loewis]

The characters are forbidden both in raw form *and* in escaped form. So even if they get escaped, they *still* will lead to errors. So there is no point in escaping them.