[petsc-dev] Commit squashing in MR

Tue Mar 2 22:20:58 CST 2021

> On Mar 2, 2021, at 10:09 PM, Jacob Faibussowitsch <jacob.fai at gmail.com> wrote:
> 
>>   I do not get this. I thought that rebasing with main put all the main changes in before your commits. I have never seen any interspersed, so I do not understand this.
> 
> Mark, do you rebase your branch over main first or do you merge main intro your branch to update it? If you rebase, you can pick an N such that you only get your commits from the branch.

   I just do 

    git rebase main   (from my branch) 

 I don't need to provide an N, it automatically puts all the new changes in main BEFORE my commits in my branch. I would never merge my branch with main.

I put the N in when I am rebasing my branch "against itself" and trying to organize the commits within my branch. By having the N be within the range of my commits it means I am just reorganizing my commits and not messing with any previous commits that came before my branch.

> 
> Best regards,
> 
> Jacob Faibussowitsch
> (Jacob Fai - booss - oh - vitch)
> Cell: (312) 694-3391
> 
>> On Mar 2, 2021, at 22:02, Barry Smith <bsmith at petsc.dev <mailto:bsmith at petsc.dev>> wrote:
>> 
>> 
>> 
>>> On Mar 2, 2021, at 9:24 PM, Mark Adams <mfadams at lbl.gov <mailto:mfadams at lbl.gov>> wrote:
>>> 
>>> Ah, 'git graph' I will try that next time.
>>> 
>>> I use 'git rebase -i HEAD~N', but you need an N. 
>>> 
>>> After you 'git rebase origin/main' you get other commits interspersed in with yours,
>> 
>>    I do not get this. I thought that rebasing with main put all the main changes in before your commits. I have never seen any interspersed, so I do not understand this.
>> 
>>   Barry
>> 
>>> so I try to rebase -i before rebasing over main. Then rebase over main and you have a clean and updated branch. 
>>> 
>>> Pick N to be large enough to cover the commits that you want to clean up. Don't touch the ones that are not yours from main, the last time you rebased over main.
>>> 
>>> On Tue, Mar 2, 2021 at 10:02 PM Junchao Zhang <junchao.zhang at gmail.com <mailto:junchao.zhang at gmail.com>> wrote:
>>> I am a naive git user, so I use interactive git rebase.  Suppose I am on the branch I want to modify, 
>>> 
>>> 1) Use git graph to locate an upstream commit to be used as the base
>>> $ git graph
>>> * 0d5433e9 (HEAD -> jczhang/sf-change-api) SF: rename SFCreateEmbeddedSF to SFCreateEmbeddedRootSF
>>> * e7314fbb SF: add an MPI_Op argument to SFBcast
>>> * 83df288d Replace MPIU_REPLACE with MPI_REPLACE
>>> *   b434c516 Merge branch 'barry/2021-02-02/petscsf-communication-specific' into 'main'
>>> |\
>>> | * 62152ded (barry/2021-02-02/petscsf-communication-specific) PetscSFView() never called viewer for the specific type (bug), hence many output files were incorrect.
>>> * |   a4f5d9b4 Merge branch 'jose/upgrade-magma' into 'main'
>>> 
>>> 2) Suppose we choose b434c516 as the base. All commits we want to squash are after it.  Do interactive git rebase. It shows a screen for you to edit.  Read the help, which is helpful for new users
>>>   $ git rebase -i b434c516
>>> pick 83df288d Replace MPIU_REPLACE with MPI_REPLACE
>>> pick e7314fbb SF: add an MPI_Op argument to SFBcast
>>> pick 0d5433e9 SF: rename SFCreateEmbeddedSF to SFCreateEmbeddedRootSF
>>> 
>>> # Rebase b434c516..0d5433e9 onto b434c516 (3 commands)
>>> #
>>> # Commands:
>>> # p, pick <commit> = use commit
>>> # r, reword <commit> = use commit, but edit the commit message
>>> # e, edit <commit> = use commit, but stop for amending
>>> # s, squash <commit> = use commit, but meld into previous commit
>>> # f, fixup <commit> = like "squash", but discard this commit's log message
>>> # x, exec <command> = run command (the rest of the line) using shell
>>> # b, break = stop here (continue rebase later with 'git rebase --continue')
>>> # d, drop <commit> = remove commit
>>> # l, label <label> = label current HEAD with a name
>>> # t, reset <label> = reset HEAD to a label
>>> # m, merge [-C <commit> | -c <commit>] <label> [# <oneline>]
>>> # .       create a merge commit using the original merge commit's
>>> # .       message (or the oneline, if no original merge commit was
>>> # .       specified). Use -c <commit> to reword the commit message.
>>> #
>>> # These lines can be re-ordered; they are executed from top to bottom.
>>> #
>>> # If you remove a line here THAT COMMIT WILL BE LOST.
>>> #
>>> # However, if you remove everything, the rebase will be aborted.
>>> #
>>> # Note that empty commits are commented out
>>> 
>>> 3) Suppose we want to squash the last two commits to 83df288d, replace their pick with s (or f, see the help for difference), save and exit the screen
>>> pick 83df288d Replace MPIU_REPLACE with MPI_REPLACE
>>> s e7314fbb SF: add an MPI_Op argument to SFBcast
>>> s 0d5433e9 SF: rename SFCreateEmbeddedSF to SFCreateEmbeddedRootSF
>>> 
>>> A new screen shows up
>>> 
>>> # This is a combination of 3 commits.
>>> # This is the 1st commit message:
>>> 
>>> Replace MPIU_REPLACE with MPI_REPLACE
>>> 
>>> Since we believe all MPI implementations support MPI_REPLACE
>>> 
>>> # This is the commit message #2:
>>> 
>>> SF: add an MPI_Op argument to SFBcast
>>> 
>>> # This is the commit message #3:
>>> 
>>> SF: rename SFCreateEmbeddedSF to SFCreateEmbeddedRootSF
>>> 
>>> # Please enter the commit message for your changes. Lines starting
>>> # with '#' will be ignored, and an empty message aborts the commit.
>>> 
>>> 4) Edit the commit message as you want, save and exit, done!
>>> 
>>> --Junchao Zhang
>>> 
>>> 
>>> On Tue, Mar 2, 2021 at 6:19 PM Blaise A Bourdin <bourdin at lsu.edu <mailto:bourdin at lsu.edu>> wrote:
>>> Hi,
>>> 
>>> This is not technically a petsc question. 
>>> It would be great to have a short section in the PETSc integration workflow document explaining how to squash commits in a MR for git-impaired developers like me.
>>> 
>>> Anybody wants to pitch in, or explain me how to do this?
>>> 
>>> Regards,
>>> Blaise
>>> 
>>> -- 
>>> A.K. & Shirley Barton Professor of  Mathematics
>>> Adjunct Professor of Mechanical Engineering
>>> Adjunct of the Center for Computation & Technology
>>> Louisiana State University, Lockett Hall Room 344, Baton Rouge, LA 70803, USA
>>> Tel. +1 (225) 578 1612, Fax  +1 (225) 578 4276 Web http://www.math.lsu.edu/~bourdin <http://www.math.lsu.edu/~bourdin>
>>> 
>> 
> 

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