[Rd] Why R should never move to git

Martin Morgan martin.morgan at roswellpark.org
Thu Jan 25 15:19:47 CET 2018


On 01/25/2018 07:09 AM, Duncan Murdoch wrote:
> On 25/01/2018 6:49 AM, Dirk Eddelbuettel wrote:
>>
>> On 25 January 2018 at 06:20, Duncan Murdoch wrote:
>> | On 25/01/2018 2:57 AM, Iñaki Úcar wrote:
>> | > For what it's worth, this is my workflow:
>> | >
>> | > 1. Get a fork.
>> | > 2. From the master branch, create a new branch called 
>> fix-[something].
>> | > 3. Put together the stuff there, commit, push and open a PR.
>> | > 4. Checkout master and repeat from 2 to submit another patch.
>> | >
>> | > Sometimes, I forget the step of creating the new branch and I put my
>> | > fix on top of the master branch, which complicates things a bit. But
>> | > you can always rename your fork's master and pull it again from
>> | > upstream.
>> |
>> | I saw no way to follow your renaming suggestion.  Can you tell me the
>> | steps it would take?  Remember, there's already a PR from the master
>> | branch on my fork.  (This is for future reference; I already followed
>> | Gabor's more complicated instructions and have solved the immediate
>> | problem.)
>>
>> 1)  Via GUI: fork or clone at github so that you have URL to use in 2)
> 
> Github would not allow me to fork, because I already had a fork of the 
> same repository.  I suppose I could have set up a new user and done it.
> 
> I don't know if cloning the original would have made a difference. I 
> don't have permission to commit to the original, and the 
> manipulateWidget maintainers wouldn't be able to see my private clone, 
> so I don't see how I could create a PR that they could use.
> 
> Once again, let me repeat:  this should be an easy thing to do.  So far 
> I'm pretty convinced that it's actually impossible to do it on the 
> Github website without hacks like creating a new user.  It's not trivial 
> but not that difficult for a git expert using command line git.
> 
> If R Core chose to switch the R sources to use git and used Github to 
> host a copy, problems like mine would come up fairly regularly.  I don't 
> think R Core would gain enough from the switch to compensate for the 
> burden of dealing with these problems.

A different starting point gives R-core members write access to the 
R-core git, which is analogous to the current svn setup. A restricted 
set of commands are needed, mimicking svn

   git clone ...   # svn co
   git pull        # svn up
   [...; git commit ...]
   git push ...    # svn ci

Probably this would mature quickly into a better practice where new 
features / bug fixes are developed on a local branch.

A subset of R-core might participate in managing pull requests on a 
'read only' Github mirror. Incorporating mature patches would involve 
git, rather than the Github GUI. In one's local repository, create a new 
branch and pull from the repository making the request

   git checkout -b a-pull-request master
   git pull https://github.com/a-user/their.git their-branch

Check and modify, then merge locally and push to the R-core git

   ## identify standard / best practice for merging branches
   git checkout master
   git merge ... a-pull-request
   git push ...

Creating pull requests is a problem for the developer wanting to 
contribute to R, not for the R-core developer. As we've seen in this 
thread, R-core would not need to feel responsible for helping developers 
create pull requests.

Martin Morgan

> 
> Maybe Gitlab or some other front end would be better.
> 
> Duncan Murdoch
> 
>>
>> 2)  Run
>>        git clone giturl....
>>      to fetch local instance
>> 3)  Run
>>        git checkout -b feature/new_thing_a
>>      (this is 2. above by Inaki)
>> 4)  Edit, save, compile, test, revise, ... leading to 1 or more commits
>>
>> 5)  Run
>>        git push origin
>>      standard configuration should have remote branch follow local 
>> branch, I
>>      think the "long form" is
>>        git push --set-upstream origin feature/new_thing_a
>>
>> 6)  Run
>>        git checkout -
>>      or
>>        git checkout master
>>      and you are back in master. Now you can restart at my 3) above for
>>      branches b, c, d and create independent pull requests
>>
>> I find it really to have a bash prompt that shows the branch:
>>
>>      edd at rob:~$ cd git/rcpp
>>      edd at rob:~/git/rcpp(master)$ git checkout -b 
>> feature/new_branch_to_show
>>      Switched to a new branch 'feature/new_branch_to_show'
>>      edd at rob:~/git/rcpp(feature/new_branch_to_show)$ git checkout -
>>      Switched to branch 'master'
>>      Your branch is up-to-date with 'origin/master'.
>>      edd at rob:~/git/rcpp(master)$ git branch -d feature/new_branch_to_show
>>      Deleted branch feature/new_branch_to_show (was 5b25fe62).
>>      edd at rob:~/git/rcpp(master)$
>>
>> There are few tutorials out there about how to do it, I once got mine 
>> from
>> Karthik when we did a Software Carpentry workshop.  Happy to detail 
>> off-list,
>> it adds less than 10 lines to ~/.bashrc.
>>
>> Dirk
>>
>> |
>> | Duncan Murdoch
>> |
>> | > Iñaki
>> | >
>> | >
>> | >
>> | > 2018-01-25 0:17 GMT+01:00 Duncan Murdoch <murdoch.duncan at gmail.com>:
>> | >> Lately I've been doing some work with the manipulateWidget 
>> package, which
>> | >> lives on Github at
>> | >> https://github.com/rte-antares-rpackage/manipulateWidget/.  Last 
>> week I
>> | >> found a bug, so being a good community member, I put together a 
>> patch.
>> | >>
>> | >> Since the package lives on Github, I followed instructions to put 
>> together a
>> | >> "pull request":
>> | >>
>> | >> - I forked the main branch to my own Github account as
>> | >> <https://github.com/dmurdoch/manipulateWidget>.
>> | >>
>> | >> - I checked out my fork into RStudio.
>> | >>
>> | >> - I fixed the bug, and submitted the pull request
>> | >> <https://github.com/rte-antares-rpackage/manipulateWidget/pull/47>.
>> | >>
>> | >> Then I felt good about myself, and continued on with my work.  
>> Today I
>> | >> tracked down another bug, unrelated to the previous one.  I know 
>> enough
>> | >> about git to know that I shouldn't commit this fix to my fork, 
>> because it
>> | >> would then become part of the previous pull request.
>> | >>
>> | >> So I created a branch within my fork, and committed the change 
>> there. But
>> | >> Github provides no way to create a pull request that only 
>> includes the new
>> | >> stuff!  Every attempt I made would have included everything from 
>> both bug
>> | >> fixes.
>> | >>
>> | >> I've read online about creating a new branch based on the master 
>> copy, and
>> | >> "cherry picking" just the final change:  but all the instructions 
>> I've tried
>> | >> so far have failed.
>> | >>
>> | >> Okay, I know the solution:  I need to burn the whole thing down 
>> (to quote
>> | >> Jenny Bryan).  I'll just create a new fork, and put the new bug 
>> fix in a
>> | >> branch there.
>> | >>
>> | >> I can't!  I don't know if this is a Git restriction or a Github 
>> restriction,
>> | >> but it won't let me create a new fork without deleting the old 
>> one.  I don't
>> | >> know if deleting the previous fork would also delete the previous 
>> PR, so I'm
>> | >> not going to do this.
>> | >>
>> | >> This is ridiculous!  It is such an easy concept:  I want to take 
>> the diff
>> | >> between my most recent commit and the one before, and send that 
>> diff to the
>> | >> owners of the master copy.  This should be a trivial (and it is 
>> in svn).
>> | >>
>> | >> Git and Github allow the most baroque arrangements, but can't do 
>> this simple
>> | >> task.  That's an example of really bad UI design.
>> | >>
>> | >> Duncan Murdoch
>> | >>
>> | >> ______________________________________________
>> | >> R-devel at r-project.org mailing list
>> | >> https://stat.ethz.ch/mailman/listinfo/r-devel
>> | >
>> | >
>> | >
>> |
>> | ______________________________________________
>> | R-devel at r-project.org mailing list
>> | https://stat.ethz.ch/mailman/listinfo/r-devel
>>
> 
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