dolfin team mailing list archive

["Garth N. Wells" <gnw20@xxxxxxxxx>]

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.

Garth

> --
> Anders