[petsc-dev] All petsc-dev users will need to do a reclone of petsc-dev on Tuesday or later

Tue Mar 12 10:11:59 CDT 2013

Though, with the exception of the Jed/Sean types who know the admin-level details of git vs. hg, I'd say going from hg 
to git is analogous to going from cvs to subversion.  For those domain scientists who have trouble even doing that, I'd 
recommend graphical tools like Meld or Tortoise to ease the transition (although PETSc's directory structure makes Meld 
especially slow).

- tim

On 03/12/2013 09:33 AM, Mark F. Adams wrote:
>
> On Mar 11, 2013, at 11:08 PM, Richard Tran Mills <rtm at eecs.utk.edu> wrote:
>
>> 1) Jed, what did you do to Barry? =) 2) I am am going to interpret the move from Mercurial to Git as a sign that
>> the End Times are indeed here.
>>
>> OK, seriously, I am OK with using Git or Mercurial: I think they are actually fairly similar tools and each has
>> pluses and minuses.  But what I do want to advocate for is that we please try to to keep some sort of Mercurial
>> access to petsc-dev in place, either by keeping a Mercurial repo around or by maintaining some clear instructions
>> on how this can be done using something like the Hg-Git plugin.  My concern is that, while I am a Ph.D. computer
>> scientist, most of the people I write code with are not (they are domain scientists), and the Git learning curve is
>> *steep*.  I have a hard enough time getting some of them comfortable with using Mercurial, and I see trying to do
>> the same with Git as a potentially hopeless task.
>>
>
> Richard,
>
> I'm in a similar situation with the plasma physicists in the EPSI project at PPPL.  They recently put their SVN repo
> behind the PPPL fire wall (I had to wait two weeks for a fob and take a 45 min. cyber security course) and that is so
> patently lame that I setup a git repo on bitbucket.org and they have been playing with it.
>
> They seem to like it and it looks like we will be moving over to git.  They are going from SVN to git.  A steeper
> climb.  These are not sophisticated users, as far as this sort of stuff, and they seem to be willing to deal with it.
> (Some of the more ambitious ones actually really like the branching mechanism is git.)  For the simple workflows that
> most scientist will use git is not much different from even svn.  And git is pretty good about giving useful
> messages.
>
>
>> --Richard
>>
>> On 3/11/13 2:05 PM, Barry Smith wrote:
>>> To users of petsc-dev,
>>>
>>> I promised more details on the planned change and why we are making them.
>>>
>>> The plan is to move petsc-dev over to the git repository system (remaining on bitbucket.org so no new accounts
>>> are needed) with a simple and slow transition from Mecurial and allowing people to change their workflows slowly
>>> and easily and NOT to drop a totally new system onto everyone at the same time. Thus on Tuesday we will be moving
>>> all the data over to git and providing access from bitbucket.org with BOTH hg and git, you will not need to
>>> switch over to git on Tuesday and in fact we recommend not switching to git immediately but continuing to use hg
>>> (on the new repository) until we have the git process documented and can help people with it. On Tuesday we will
>>> be sending out the URL of the new hg repository you should clone from at that time.
>>>
>>> If you are in the middle of a coding project that you don't want to push immediately send us
>>> petsc-maint at mcs.anl.gov and we'll get things organized so that you can continue with that in the new repository.
>>>
>>> Schedule: Tuesday -- delete your current petsc-dev repositories and reclone with hg using the new URL, use this
>>> new repository just like the current one After Tuesday -- read our documentation on using Git (to be sent out
>>> later)  and then eventually switch to accessing petsc-dev via git. Eventually -- the Mecurial (hg) access to
>>> petsc-dev will become read only.
>>>
>>> Reasons for the change:
>>>
>>> 1)  We want to provide a more stable version of petsc-dev. To often petsc-dev won't compile cleanly when pulled.
>>> In our new model this will happen much less often since code will be well tested before being pushed into the
>>> stable version.
>>>
>>> 2) The petsc-dev repository has gotten overly large due to many large binary files being accidentally added to
>>> the repository, thus it is time to get rid of those files and that requires a reclone.
>>>
>>> 3) We would like to make the change sets and histories in petsc-dev be more logically related to particular
>>> projects and not just a random bunch of unrelated changes (as Barry has often done). Our new work flow with git
>>> will help with this.
>>>
>>> 4) Though Mecurial is a user friendly system, git appears to have more community support and thus is likely to
>>> have more capabilities and utilities developed for it in the future. We will strive to make the use of git with
>>> PETSc as simple as possible.
>>>
>>> I have been hesitant to make this change for fear that working with petsc-dev would become more cumbersome, more
>>> annoying, more bookkeeping involved, more like a job, and hence less fun. And we know people tend to do something
>>> less if it is less fun. Since we don't want people to do things with petsc-dev less we will be trying hard to
>>> make the new model as close to the old model as possible and not cumbersome or annoying.  As always we appreciate
>>> any feedback on what we are doing wrong and how we could improve it.
>>>
>>> Barry
>>>
>>>
>>> On Mar 10, 2013, at 10:29 PM, Barry Smith <bsmith at mcs.anl.gov> wrote:
>>>
>>>> To everyone accessing petsc-dev via Mecurial (hg),
>>>>
>>>> We are reorganizing how we handle the petsc-dev/BuildSystem repository. In step one everyone will need to
>>>> delete all their clones of petsc-dev and then reclone them either on Tuesday or soon after. So it would be good
>>>> if anyone who has material close to being ready to push to petsc-dev to finish it up and push it before then.**
>>>> (If you are a user of petsc-dev but do not edit any files in petsc-dev you will also need to do the reclone.)
>>>>
>>>> We will send out more warnings reminding you of the change and the location of the new URL to clone from. We
>>>> will also send out a more complete message explaining all the planned changes and why we are making them. Aside
>>>> from this first recloning, the changes will not require any immediate change in the way you interact with
>>>> petsc-dev.
>>>>
>>>>
>>>> Barry
>>>>
>>>> ** If you miss the deadline, but have changes that still need to be submitted, we can handle that but it will
>>>> be  manual process so we do not want too much of that.
>>>>
>>
>>
>> -- Richard Tran Mills, Ph.D. Computational Earth Scientist      | Joint Assistant Professor Hydrogeochemical
>> Dynamics Team     | EECS and Earth & Planetary Sciences Oak Ridge National Laboratory      | University of
>> Tennessee, Knoxville E-mail: rmills at ornl.gov  V: 865-241-3198 http://climate.ornl.gov/~rmills
>>
>>
>
>

-- 
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              Tim Tautges            Argonne National Laboratory
          (tautges at mcs.anl.gov)      (telecommuting from UW-Madison)
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