Comment 2 for bug 788349

Hi James,

On May 25, 2011, at 10:08 PM, James Westby wrote:

>On Wed, 25 May 2011 21:26:00 -0000, Barry Warsaw <email address hidden> wrote:
>> Of course, it would be nice if bzr bd could do this for you, so you
>> don't have to remember to do it, and so that you can't mess it up. I
>> *think* bzr should be able to figure out the last Ubuntu version by
>> looking at the tags. If the last version was not an Ubuntu version,
>> then it should be possible to automatically supply -v to dpkg-
>> buildsource, which forwards it to dpkg-genchanges.
>
>It's not possible for bzr-builddeb to reliably detect this. Check out
>the --package-merge option. Try using this when you are building the
>package in the situation you describe.

I just tried this on python-support, where we have 1.0.10ubuntu3 and I'm
merging up to Debian's 1.0.13 with an additional 1.0.13ubuntu1 to keep our
Ubuntu specific changes. Looking in the _source.changes file, I see the
changelog entries for

1.0.13ubuntu1
1.0.13
1.0.12
1.0.11

which I think makes sense, given that the next change down is 1.0.10ubuntu3.

So it looks like --package-merge is doing what I want, but I'm curious. Why
is it not possible to reliably detect this? Does it make sense to always
provide --package-merge or will that do bad things in some cases?

Also, the help docs are only somewhat helpful:

  --package-merge Build using the appropriate -v and -sa options for
                        merging in the changes from another source.

Okay, I understand what the first half of that means, but what does "merging
in the changes from another source" actually *mean*? ;)

If it's really not possible for bd to always DTRT, how can we improve both the
help text and discoverability of this option?

Cheers,
-Barry