[git-buildpackage] extra newline in gbp.deb.changelog

[Guido Günther]

Hi Ken,
On Mon, Nov 06, 2017 at 03:21:46PM -0700, Ken Dreyer wrote:
> Here's a really simple debian/changelog file:
> 
> $ cat debian/changelog
> testpkg (1.0.0-1) xenial; urgency=low
> 
>   * Initial package
> 
>  -- Ken Dreyer <kdreyer at redhat.com>  Tue, 06 Jun 2017 14:46:37 -0600
> 
> 
> The following code works slightly differently between Python 2 (eg.
> git-buildpackage 0.7.2) and Python 3 (with gbp master):
> 
>     from gbp.deb.changelog import ChangeLog
>     clog = ChangeLog(filename='debian/changelog')
>     clog['Changes']
> 
> In Python 2 (old gbp versions), the clog['Changes'] string is not
> prefixed with a newline. It simply starts with the first line of
> debian/changelog (well, prefixed by dpkg-parsechangelog's
> indentation). In Python 3 (gbp master), the string always starts with
> a spurious newline as the first character.
> 
> The key difference is that Python 2's message_from_string() would
> discard the newline that dpkg-parsechangelog prints after "Changes:".
> Python 3 does not discard this newline.
> 
> I'm not sure what is more "correct".
> 
> Does it make sense for gbp to go back to the old behavior?
> 
> We could do something like:
> 
> diff --git a/gbp/deb/changelog.py b/gbp/deb/changelog.py
> index 33d83c1..e6c9176 100644
> --- a/gbp/deb/changelog.py
> +++ b/gbp/deb/changelog.py
> @@ -118,6 +118,11 @@ class ChangeLog(object):
>                  cp['Upstream-Version'], cp['Debian-Version'] =
> cp['NoEpoch-Version'].rsplit('-', 1)
>              else:
>                  cp['Debian-Version'] = cp['NoEpoch-Version']
> +            # py3's email.message_from_string() saves dpkg-parsechangelog's
> +            # first newline from the "Changes" field.
> +            changes = cp['Changes'].lstrip("\n")
> +            del cp['Changes']
> +            cp['Changes'] = changes
>          except TypeError:
>              raise ParseChangeLogError(output.split('\n')[0])

That makes sense. I've pushed this with a testcase added.

> If not, I can handle this difference in my wrapper application. I'm
> curious what others think about this.
> 
> My end goal is to get the actual "Changes" (bulleted items) in the
> /debian/changelog file. Maybe I should make my application just scan

The current classes aren't very comfortable when it comes to that but
what about adding a method that returns already parsed entries by
extending the ChangelogSection class?

Cheers,
 -- Guido

> all text "Changes" text until it finds " .\n", since that is
> unchanging here.