#114 rst2odt_prepstyles.py: Port to ElementTree

rst2odt_prepstyles.py currently uses lxml to parse, modify and write XML. The attached patch makes it use ElementTree instead, which has been part of Python's standard library since 2.5.

[Dmitry Shachnev]

Here is a revised version of this patch, which also adds Python 3 compatibility (by using correct Except: statements and sys.stderr.write).

[Dmitry Shachnev]

Dear Docutils developers, can you please comment on this ticket? (And probably other ones in "patches" group).

[engelbert gruber]

i am trying.
please (leave the patch here) and move discussion to
https://sourceforge.net/p/docutils/bugs/255/

[Günter Milde]

With [bugs:#255] solved and changes to the source (to make it Py3k-conform), is there an advantage of using elementtree that makes it worth updating, testing, and applying the patch ?

[Dmitry Shachnev]

lxml is not part of standard library, while xml.etree is. So we are adding a dependency on a 3rdparty project for no good reason.

I am attaching a version of this patch which applies cleanly to master branch of git mirror.

[Günter Milde]

lxml is not part of standard library, while xml.etree is.

I see. Thanks for the clarification.

When I try to use the patched script on a copy of docutils/writers/odf_odt/styles.odt, I get an error:

/usr/local/src/docutils-git-svn/docutils/tools/rst2odt_prepstyles.py styles.odt 
Traceback (most recent call last):
  File "/usr/local/src/docutils-git-svn/docutils/tools/rst2odt_prepstyles.py", line 78, in <module>
main()
  File "/usr/local/src/docutils-git-svn/docutils/tools/rst2odt_prepstyles.py", line 74, in main
prepstyle(filename)
  File "/usr/local/src/docutils-git-svn/docutils/tools/rst2odt_prepstyles.py", line 48, in prepstyle
for attr in el.attrib.keys():
RuntimeError: dictionary changed size during iteration

BTW, the non-patched version fails with:

/usr/local/src/docutils-git-svn/docutils/tools/rst2odt_prepstyles.py styles.odt 
Traceback (most recent call last):
  File "/usr/local/src/docutils-git-svn/docutils/tools/rst2odt_prepstyles.py", line 67, in <module>
    main()
  File "/usr/local/src/docutils-git-svn/docutils/tools/rst2odt_prepstyles.py", line 63, in main
    prepstyle(filename)
  File "/usr/local/src/docutils-git-svn/docutils/tools/rst2odt_prepstyles.py", line 49, in prepstyle
    zout.writestr(item, zin.read(item.filename))
  File "/usr/lib/python3.9/zipfile.py", line 1802, in writestr
    with self.open(zinfo, mode='w') as dest:
  File "/usr/lib/python3.9/zipfile.py", line 1505, in open
    return self._open_to_write(zinfo, force_zip64=force_zip64)
  File "/usr/lib/python3.9/zipfile.py", line 1600, in _open_to_write
    self.fp.write(zinfo.FileHeader(zip64))
TypeError: write() argument must be str, not bytes
Exception ignored in: <function ZipFile.__del__ at 0x7f7e5b555700>
Traceback (most recent call last):
  File "/usr/lib/python3.9/zipfile.py", line 1807, in __del__
    self.close()
  File "/usr/lib/python3.9/zipfile.py", line 1825, in close
    self._write_end_record()
  File "/usr/lib/python3.9/zipfile.py", line 1919, in _write_end_record
    self.fp.write(endrec)
TypeError: write() argument must be str, not bytes

[Dmitry Shachnev]

First error can be fixed by replacing el.attrib.keys() with list(el.attrib). Second error can be fixed by changing argument of os.fdopen from w to wb.

I am attaching an updated version of the patch. Although you may want to commit w to wb change as a separate revision, for ease of backporting.

[Günter Milde]

Applied in [r9365].
(Without the handling of Python <2.5 as we no longer support Python 2.)

Thank you for the patch.

[Günter Milde]

Fixed in Docutils 0.20
Thanks for the patch and explanations.