Comment 6 for bug 84043

One interesting possible workaround.

    tmp_fileno, msgfilename = tempfile.mkstemp(prefix='bzr_log.',
                                               dir=u'.',
                                               text=True)
    msgfile = os.fdopen(tmp_fileno, 'w')

When we create the file we know that we are creating it in the current working directory.

mkstemp always returns the full path of the new file. But if we know we used "dir='.'" then we can turn around and use:
msgfilename = osutils.basename(msgfilename)

Would someone be able to try this?