Issue2413

This seems to be a variation of #1479. To reproduce:

E:\>jython
Jython 2.7.0 (default:9987c746f838, Apr 29 2015, 02:25:11)
[Java HotSpot(TM) Client VM (Oracle Corporation)] on java1.8.0_60
Type "help", "copyright", "credits" or "license" for more information.
>>> from xml.etree import ElementTree as ET
>>> elem = ET.XML('<test/>')
>>> tree = ET.ElementTree(elem)
>>> tree.write('test.xml', encoding='blaaaah')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "C:\jython2.7.0\Lib\xml\etree\ElementTree.py", line 818, in write
    qnames, namespaces = _namespaces(
  File "C:\jython2.7.0\Lib\xml\etree\ElementTree.py", line 886, in _namespaces
    add_qname(tag)
  File "C:\jython2.7.0\Lib\xml\etree\ElementTree.py", line 870, in add_qname
    qnames[qname] = encode(qname)
  File "C:\jython2.7.0\Lib\xml\etree\ElementTree.py", line 870, in add_qname
    qnames[qname] = encode(qname)
  File "C:\jython2.7.0\Lib\xml\etree\ElementTree.py", line 845, in encode
    return text.encode(encoding)
LookupError: unknown encoding 'blaaaah'
>>> import os
>>> os.remove('test.xml')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
OSError: unlink(): an unknown error occurred: E:\test.xml


A workaround is opening and closing output files explicitly:

    with open('test.xml', 'wb') as output:
        tree.write(output, ...)

The fix is more or less the workaround Peke identified; in https://github.com/jythontools/jython/blob/master/lib-python/2.7/xml/etree/ElementTree.py#L789 which defines the write method, opened files must always be closed via a finally. I assume this never came up on non refcounted systems, and presumably it could be also a bug in PyPy today for example. Adding Phil...

It is not fixed in current CPython 2.7 source:
https://github.com/python/cpython/blob/2.7/Lib/xml/etree/ElementTree.py#L787

Yeah, I would assume the same bug appears everywhere that uses CPython ElementTree but doesn't have refcounting GC. It is obviously pretty minor compared to #1479. I only noticed it because we had a test for invalid encoding and subsequent tests started to fail.

Yup. The other fix was applied to CPython's Lib, so this one should definitely be fixed over there too

Phil, are we still seeing updates against CPython 2.7 that are not security related? We haven't bothered sending updates to upstream for quite a while in Jython 2.7, because that's been our assumption.

Let's see if we can get this fixed for 2.7.1, it is pretty easy to do so. We can look at upstreaming later.

Fix now the xml stdlib has been updated (#2124). Just requires a minimal patch of course.

Target RC

I'll take, as you've made it so easy.

Not quite so easy. Well, this particular bug is ok, but in attempting to add a doctest to test_xml_etree_jy, I find that quite a few other tests also fail. We'll handle those separately in #2518.

Stepping out of the time machine in 2009, it's the same :(

Fixed as of https://hg.python.org/jython/rev/c168765aae66

But at least a fair number of gains since 2009, even if the progress is incremental. Hopefully Jython 3 will get us closer to the front and really seeing these fixes pushed up.