Testing/feedback wanted: Using dpkg-mergechangelogs in bzr-builddeb

[Andrew Bennetts]

James Westby wrote:
[…]
> bzrlib.plugins.builddeb.tests.test_merge_changelog.TestMergeChangelog.test_not_valid_changelog
> 
> This is testing what happens with an invalid changelog. I'm not sure
> what the effect of returning "not_applicable" versus "success" with the
> invalid text would be. I don't think it's a particularly important case
> though.

“not_applicable” gives other merge hooks, including the default one
(which is always applicable, but might conflict), a chance to try the
merge.  The other outcomes (“success”, “conflicted” and “deleted”) are
final result for the merge.

So that test is saying “if it's not a valid changelog, give up and let
the default logic (or other plugins) merge it.”  I agree that that
doesn't seem particularly important.  The main thing I think is that
invalid changelogs shouldn't cause tracebacks or other completely
unreasonable output (and *perhaps* ideally also produce a gentle warning).
If so, “success” vs. “not_applicable” are both fine, assuming the
apparent success isn't actually total garbage.

> bzrlib.plugins.builddeb.tests.test_merge_changelog.TestMergeChangelog.test_3way_conflicted
> 
> Getting success back in this case seems wrong.

Hmm, I can see a good argument for success here, actually.  This looks
like a successful three-way merge:

> The text it returns is:
> 
>  psuedo-prog (1.1.1-2) unstable; urgency=low
> 
>    * New upstream release.
>    * Yet another content for 1.1.1-2
>    * But more is better
> 
>   -- Joe Foo <joe at example.com>  Thu, 28 Jan 2010 10:45:44 +0000
> 
> and I'm not sure that's correct as it's discarding a line.
> 
> If it's the desired behaviour of dpkg-mergechangelog then it may be what
> we want, but it seems odd to me.

BASE → OTHER deletes the “Awesome bug fixes.” line, and adds the “Yet
another…” line.  BASE → THIS just adds “But more is better”.  So that
output looks like a sensible and expected combination of those changes:
it's what I'd do if I had to merge those by hand.  But as a VCS
developer perhaps my sense of what's expected is skewed ;)

Given that one side does discard a line, do you still find it odd that
the merge also discards that line?

-Andrew.