Quote in doctype systemliteral

[Olli Pottonen]

XML 1.0 standard specifies that document type declaration system literal must be of the form

('"' [^"]* '"') | ("'" [^']* "'")

[http://www.w3.org/TR/REC-xml/#sec-prolog-dtd]

That is, it is anything that starts and ends with hyphen, or starts and ends with quote.
Especially, it may be a string which starts with hyphen, contains a quote, and end swith hyphen.
That is, these both are valid:

<!DOCTYPE a PUBLIC 'foo' '"'><a/>
<!DOCTYPE a SYSTEM '"'><a/>

However, both cases break lxml:
>>> import lxml.etree
>>> doc = lxml.etree.XML('''<!DOCTYPE a PUBLIC 'foo' '"'><a/>''').getroottree()
>>> doc.docinfo.doctype
u'<!DOCTYPE a PUBLIC "foo" """>'
>>> lxml.etree.tostring(doc)
'<!DOCTYPE a PUBLIC "foo" """>\n<a/>'
>>>
>>> doc = lxml.etree.XML('''<!DOCTYPE a SYSTEM '"'><a/>''').getroottree()
>>> doc.docinfo.doctype
u'<!DOCTYPE a SYSTEM """>'
>>> lxml.etree.tostring(doc)
'<!DOCTYPE a SYSTEM """>\n<a/>'

[scoder (scoder)]

proposed fix:
https://github.com/opottone/lxml/commit/711c4eccf90f727d87d3cbeb9c28fb326cf2acbd

[scoder (scoder)]

https://github.com/lxml/lxml/commit/682d007c999520d73e25559aa8b94e86c16b8302

[scoder (scoder)]

Fixed in lxml 3.5.0.