dolfin team mailing list archive

[Anders Logg <logg@xxxxxxxxx>]

On Fri, Jun 17, 2011 at 10:33:23AM +0100, Garth N. Wells wrote:
>
>
> On 17/06/11 10:28, Anders Logg wrote:
> > On Fri, Jun 17, 2011 at 11:24:21AM +0200, Marie E. Rognes wrote:
> >>
> >> On 17. juni 2011, at 11:05, "Garth N. Wells" <gnw20@xxxxxxxxx> wrote:
> >>
> >>>
> >>>
> >>> On 17/06/11 09:34, Anders Logg wrote:
> >>>> On Fri, Jun 17, 2011 at 08:46:46AM +0100, Garth N. Wells wrote:
> >>>>>
> >>>>>
> >>>>> On 17/06/11 08:35, Garth N. Wells wrote:
> >>>>>>
> >>>>>>
> >>>>>> On 12/06/11 21:36, Anders Logg wrote:
> >>>>>>> On Fri, Jun 10, 2011 at 10:33:41PM +0100, Florian Rathgeber wrote:
> >>>>>>> On 11/05/11 15:43, Anders Logg wrote:
> >>>>>>>>>> On Wed, May 11, 2011 at 03:57:52PM +0200, Anders Logg wrote:
> >>>>>>>>>>> On Tue, May 10, 2011 at 10:57:07PM +0200, Martin Sandve Alnæs wrote:
> >>>>>>>>>>>> On 10 May 2011 17:52, Anders Logg <logg@xxxxxxxxx> wrote:
> >>>>>>>>>>>>> On Tue, May 10, 2011 at 03:49:18PM +0200, Martin Sandve Alnæs wrote:
> >>>>>>>>>>>>>> On 3 May 2011 18:25, Johannes Ring <johannr@xxxxxxxxx> wrote:
> >>>>>>>>>>>>>>> On Tue, May 3, 2011 at 3:52 PM, Anders Logg <logg@xxxxxxxxx> wrote:
> >>>>>>>>>>>>>>>> It happens to me a lot. Johannes has tried to explain to me why it
> >>>>>>>>>>>>>>>> happens a number of times but I still don't understand why.
> >>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>> Maybe he can try to explain it again to you and then I might also
> >>>>>>>>>>>>>>>> understand. :-)
> >>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>> I think I just bring up the following instructions (which I think looks good):
> >>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>> http://wiki.squid-cache.org/BzrInstructions
> >>>>>>>>>>>>>>
> >>>>>>>>>>>>>> Thanks Johannes.
> >>>>>>>>>>>>>>
> >>>>>>>>>>>>>> Basically the problem is that bazaar numbers commits with contiguous
> >>>>>>>>>>>>>> integers, and when Bob and Alice works locally they will get the same
> >>>>>>>>>>>>>> commit ids for different commits. When you stand in branch Alice and
> >>>>>>>>>>>>>> merge from branch Bob, the commit numbers of branch Alice are
> >>>>>>>>>>>>>> conserved and a single new merge commit is recorded on top there. The
> >>>>>>>>>>>>>> commit numbers from branch Bob are lost in the merge. Therefore, to
> >>>>>>>>>>>>>> conserve the commit ids in the central branch, you have to merge from
> >>>>>>>>>>>>>> your own branch into the server branch, not the other way around.
> >>>>>>>>>>>>>> Otherwise we can never safely use the commit revisions from the
> >>>>>>>>>>>>>> central branch, since they may change every time somebody merges the
> >>>>>>>>>>>>>> 'wrong way'.
> >>>>>>>>>>>>>>
> >>>>>>>>>>>>>> This problem does not occur with hg or git, because they use a hash
> >>>>>>>>>>>>>> value to identify a each commit.
> >>>>>>>>>>>>>
> >>>>>>>>>>>>> So if I'm Bob and Alice has pushed some changes to the main branch
> >>>>>>>>>>>>> before me, which exact commands should I write?
> >>>>>>>>>>>>
> >>>>>>>>>>>> Depends on how you set up your repositories, where your branches are
> >>>>>>>>>>>> located, etc...
> >>>>>>>>>>>>
> >>>>>>>>>>>> You really have to read up on it and try it out a bit to understand
> >>>>>>>>>>>> it, and I doubt I can write it better than what Johannes linked to +
> >>>>>>>>>>>> the bazaar docs.
> >>>>>>>>>>>>
> >>>>>>>>>>>> I plan to keep a local repository with multiple branches like this:
> >>>>>>>>>>>>  ~/dev/fenics/ufl/ - local ufl repository
> >>>>>>>>>>>
> >>>>>>>>>>> Is this a repository? Or is it just a directory named ufl inside which
> >>>>>>>>>>> you keep a number of different repositories?
> >>>>>>>>>>
> >>>>>>>>>> Talked to Martin during lunch. Here's a simple summary of what needs
> >>>>>>>>>> to be done to set things up correctly (Cc to dolfin-dev so everyone else
> >>>>>>>>>> sees this):
> >>>>>>>>>>
> >>>>>>>>>>  bzr init-repo foo
> >>>>>>>>>>  cd foo
> >>>>>>>>>>  bzr checkout lp:foo trunk
> >>>>>>>>>>  bzr branch trunk work
> >>>>>>>>>>
> >>>>>>>>>> We should add this to the developer page in the documentation.
> >>>>>>>>>>
> >>>>>>>>>> Everyone should adopt this and we should pick on anyone that pushes
> >>>>>>>>>> removed changesets.
> >>>>>>>
> >>>>>>> There's an effective way to make these pushes impossible and disable the
> >>>>>>> bzr "feature" of renumbering revisions: set the option
> >>>>>>> append_revisions_only=True in <yourbranch>/.bzr/branch/branch.conf
> >>>>>>>
> >>>>>>> For branches on launchpad this works as follows:
> >>>>>>> 1) sftp bazaar.launchpad.net
> >>>>>>>     cd ~user/project/branch/.bzr/branch
> >>>>>>>     get branch.conf
> >>>>>>> 2) edit the downloaded file, adding append_revisions_only = True
> >>>>>>> 3)   put branch.conf
> >>>>>>>
> >>>>>>> I suggest doing this for all branches on launchpad to enforce consistent
> >>>>>>> revision numbers.
> >>>>>>>
> >>>>>>> More background: http://stackoverflow.com/questions/5413602
> >>>>>>>
> >>>>>>>> Thanks. I've fixed this now for DOLFIN, FFC, UFL, UFC, FIAT.
> >>>>>>>
> >>>>>>
> >>>>>> Could you please undo this. I can't push changes from my personal branch
> >>>>>> to DOLFIN. I don't see that this change has any use. (If we want cvs,
> >>>>>> then we should use cvs.)
> >>>>>>
> >>>>>> I've tried to follow the instructions to undo the change, but can't get
> >>>>>> it to work.
> >>>>>>
> >>>>>
> >>>>> I've undone this for DOLFIN so I could push my changes.
> >>>>
> >>>> You should have figured out how to do the merge properly instead. We
> >>>> should add it back to force everyone to learn how to use bzr. ;-)
> >>>>
> >>>
> >>> Merge is 'bzr merge xxx'. That's a proper merge.
> >>>
> >>>> The point is to not rewrite history for the common repo. This is not
> >>>> the same as cvs. It's still distributed but it means merges have to be
> >>>> done more carefully.
> >>>>
> >>>
> >>> There is no history re-writing. It's just adding changesets. Unique
> >>> changeset numbering that bzr does will always be problematic with
> >>> distributed version control. If you want a unique identifier, use the
> >>> revision id.
> >>>
> >>>> Just do this next time and it should work:
> >>>>
> >>>> 1. Make sure you have a local bound dolfin branch:
> >>>>
> >>>>  bzr checkout lp:dolfin trunk
> >>>>
> >>>> 2. Merge *from* that branch, not push to it:
> >>>>
> >>>>  cd trunk
> >>>>  bzr merge <path to your local repo>
> >>>>  bzr commit -m merge
> >>>>
> >>>
> >>> It just worked before. It was simpler, and I could work against any
> >>> branch, like by personal branch under dolfin-core.
> >>>
> >>
> >> After trying the no-revisions-removed approach for a while, I also find it significantly more cumbersome, especially with the main vs personal branches.
> >>
> >> Although I see the point, I never encountered a problem with the changing revision numbers before.
> >
> > If Garth can't be bothered, maybe you could describe a specific
> > example that doesn't work?
> >
>
> Why would I bother with something that I think is pointless and
> cumbersome? Like Marie, I have never had a problem with the present
> approach.

I disagree. I think there is a point to it and that it's not
cumbersome.

I'm just asking for a simple example that I can try. Otherwise it's
just handwaving.

--
Anders