> On Oct 31, 2020, at 5:21 PM, Jed Brown <j...@jedbrown.org> wrote:
> 
> Barry Smith <bsm...@petsc.dev> writes:
> 
>>> On Oct 31, 2020, at 9:35 AM, Jed Brown <j...@jedbrown.org> wrote:
>>> 
>>> Barry Smith <bsm...@petsc.dev> writes:
>>> 
>>>>  I have no problem updating any of Ed's examples if we need to with each 
>>>> release, so the burdern doesn't fall on him. We simply make a fork of his 
>>>> repository with a new branch and update that and make a MR to Ed for each 
>>>> release and he can have a new branch or tag of his examples for each new 
>>>> PETSc release.
>>>> 
>>>>  Barry
>>>> 
>>>> We just make this part of our release process.
>>> 
>>> If we add it to CI, the workflow is
>>> 
>> 
>> I would keep the  fork always petsc/pkg-eds-repo   and have PETSc master 
>> always point to the fork. At releases we would have release point directly 
>> to eds. 
>> This would remove the need to fork constantly I use this model partially for 
>> adol-c
>> 
>>  Anything wrong with this model?
> 
> This takes Ed out of the loop, but doesn't avoid the CI circus that I 
> outlined. It's more reproducible to always pin to a commit hash in the 
> repository, in which case there may be no need to circle back and update 
> PETSc after merging in Ed's repo (or our fork).
> 
> An alternative would be to subtree the examples into PETSc and export upon 
> release. Ed could be the CODEOWNER so he can weigh in on proposed changes or 
> more idiomatic interfaces that may become available. His repo would always 
> work with the latest release.

  What do you mean by release (six month release or all the time with master?)

  I have no problem with alternative approaches but they must truly eliminate 
part of the extra work required by my approach on everyone's part not increase 
the work. I did find some possible issues with subtree which may or may not 
apply 

https://www.atlassian.com/git/tutorials/git-subtree

Drawbacks (but in our opinion they're largely acceptable):

You must learn about a new merge strategy (i.e.git subtree).
Contributing code back upstream for the sub-projects is slightly more 
complicated.
The responsibility of not mixing super and sub-project code in commits lies 
with you.
1 and 3 seem a bit concerning, I will certainly make this mistake constantly 
without an automatic system to prevent it.

----
This is not a good sign, git subtree exists,  but
$ git help subtree
No manual entry for git-subtree

-----

Anyways back to my concern.

git subtree does require use of new commands every time you mess with it (say 
every three months) that we do not know and since each of 
us will do this infrequently it is likely we will not remember them (I won't)  
while my approach does not require remembering new commands. 
My approach only requires branching, push, and pulling on the fork and updating 
EdsRepo.py which is things all the developers know about and 
do regularly since we update other external packages.

If we all needed to use git subtree often then the extra burden of learning it 
and remembering it would just happen, but since we are 
likely to use it infrequently it is not clear to me that the extra burden of 
everyone learning subtree is truly simpler than my approach for everyone but 
you. 

Also making Ed a code owner seems to give him an extra unneeded burden by 
sending mail for every trivial fix, that he would not face if we just submitted 
MR to him when anything dramatically changes and at release time.

----
I would just put the fork of Ed's repository in a couple of pipeline tests with 
--download-edsrepo then people don't need to monkey with it themselves unless 
there is a failure and if there is a failure they proceed just like any other 
external package, add --download-edsrepository locally, fix in the downloaded 
repo, push, change the commit in edsrepo.py and push. 

In conclusion, if you can demonstrate that git subtree is truly simpler for all 
of us including Ed, then definitely we should use it. But I have my concerns 
that it actually adds a good amount of unneeded new complexity. 

 Barry


 

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