Parsing incomplete XML raises TypeError: __init__() takes at least 5 positional arguments (2 given)

[Enrico Minack]

Parsing incomplete XML raises an XMLSyntaxError. But if a bespoke target is used, it fails to instantiate the error:

    from lxml import etree

    parser = etree.XMLParser(target=etree.TreeBuilder())
    etree.fromstring('<a><b></b>', parser=parser)

    TypeError: __init__() takes at least 5 positional arguments (2 given)

The following raises the error correctly:

    parser = etree.XMLParser()
    etree.fromstring('<a><b></b>', parser=parser)

    lxml.etree.XMLSyntaxError: Premature end of data in tag a line 1, line 1, column 11

It looks like TreeBuilder.close() calls (https://github.com/lxml/lxml/blob/master/src/lxml/saxparser.pxi#L820):

    raise XMLSyntaxAssertionError("missing end tags")

which calls the XMLSyntaxError constructor with only two arguments (self and message) and not the expected 5.

This issue also surfaces when any error is raised while processing the XML, which finally closes the TreeBuilder and throws another exception, because the processed XML has unclosed tags (as processing is half-way done).

Python : sys.version_info(major=3, minor=8, micro=13, releaselevel='final', serial=0)
lxml.etree : (4, 9, 1, 0)
libxml used : (2, 9, 14)
libxml compiled : (2, 9, 14)
libxslt used : (1, 1, 35)
libxslt compiled : (1, 1, 35)

[scoder (scoder)]

Thanks. Fixed in https://github.com/lxml/lxml/commit/762f62c5a1ab62ce37397aeeab2c27fdcc14ca66