python-debian Changelog module?

[jsw at debian.org]

Hi Mark,

(Adding the project mailing list.)

On Tue, Aug 30, 2011 at 01:19:33PM +0000, Mark Kusch wrote:
> Hi, 
> 
> I wonder how python-debian Changelog module should be used to read and parse data from changelog files. 
> 
> It simply does not work, reproducable:
> - create changelog file with "simple_changelog" from examples folder
>   $ /usr/share/doc/python-debian/examples/changelog/simple_changelog > /tmp/python-debian-test.changelog
> - gather information from generated changelog file
>   >>> from debian.changelog import Changelog, Version
>   >>> chlog = Changelog('/tmp/python-debian-test.changelog')
>   >>> chlog.get_version()

The Changelog constructor takes the changelog contents as an iterable of
str or unicode lines (e.g. a file object), or a single str or unicode.
It doesn't take a filename.  You want something like

    >>> from debian import changelog
    >>> f = open('/tmp/python-debian-test.changelog')
    >>> c = changelog.Changelog(f)
    >>> c.get_version()
    Version('0.1')

It seems pretty clear in the docs:

    >>> help(changelog.Changelog)
    Help on class Changelog in module debian.changelog:
    
    class Changelog(__builtin__.object)
     |  Represents a debian/changelog file.
     |  
     |  Methods defined here:
     |  
     |  __init__(self, file=None, max_blocks=None, allow_empty_author=False, strict=True, encoding='utf-8')
     |      Initializer.
     |      
     |      Args:
     |        file: The contents of the changelog, either as a str, unicode object,
     |            or an iterator of lines (each of which is either a str or unicode)

Unfortunately, you have to get at them with an interactive interpreter
or by examining the source.  We probably should be putting epydoc output
in /usr/share/doc/python-debian.

> --------------------------------------------------------------------------
> IndexError                                Traceback (most recent call last)
> 
> /usr/lib/pymodules/python2.5/debian/changelog.pyc in get_version(self)
>     393     def get_version(self):
>     394         """Return a Version object for the last version"""
> --> 395         return self._blocks[0].version
>     396 
>     397     def set_version(self, version):
> 
> IndexError: list index out of range
> 
> 
> Problem for me is in Changelog.parse_changelog().
>    >>> chlog.parse_changelog('/tmp/python-debian-test.changelog')
> ---------------------------------------------------------------------------
> ChangelogParseError                       Traceback (most recent call last)
> 
> /usr/lib/pymodules/python2.5/debian/changelog.pyc in parse_changelog(self, file, max_blocks, allow_empty_author, strict)
>     325                             continue
>     326                     self._parse_error("Unexpected line while looking "
> --> 327                             "for %s: %s" % (state, line), strict)
>     328                     if state == first_heading:
>     329                         self.initial_blank_lines.append(line)
> 
> /usr/lib/pymodules/python2.5/debian/changelog.pyc in _parse_error(self, message, strict)
>     214     def _parse_error(self, message, strict):
>     215         if strict:
> --> 216             raise ChangelogParseError(message)
>     217         else:
>     218             warnings.warn(message)
> 
> ChangelogParseError: Could not parse changelog: Unexpected line while looking for first heading: /tmp/python-debian-test.changelog
> 
> 
> I've tried instances of Changelog with 
> - max_blocks set (e.g. 3) and default None
> - allow_empty_author True and False
> - strict True and False
> 
> in Debian package versions
> - oldstable (0.1.10)
> - lenny-backports (0.1.14~bpo50+1)
> - wheezy (0.1.21) 
> 
> in Debian Lenny on 
> - changelogs generated through debian.changelog.Changelog()
> - changelogs from Debian packages (upstream)
> - changelogs from own custom packages (following the Debian Policy chapter 4.4  "Debian changelog: debian/changelog" in http://www.debian.org/doc/debian-policy/ch-source.html)
> 
> No success at all. Because there is no time for me at work to "fix" something upstream and send in patches I hope you can help me out or possibly find problems in python-debian 
> which can get fixed upstream.
> 
> Best,
> 
> # kraM
> 
> --
> Mark Kusch
> System Administration
> 
> Bigpoint GmbH
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-- 
John Wright <jsw at debian.org>