Procedure for reverting commits on release branch

Procedure for reverting commits on release branch

[Glenn Morris]

If a commit is made on the release branch, and then one wants to instead
have it only on master, then given the following commit sequence:

1) emacs-27: do something
2) emacs-27: revert something
3) master: do something

If gitmerge.el is now used to merge emacs-27 to master:
commit 1) is skipped, because it is already on master
commit 2) is merged

Net result: 3) is reverted on master and has to be applied again by hand.

Specific recent example: lisp/calculator.el


A more efficient way to do this would be:
1) emacs-27: do something
2) emacs-27: revert something, and mark "do not merge to master"

Then no special handling is needed. 

Re: Procedure for reverting commits on release branch

[Eli Zaretskii]

> From: Glenn Morris <rgm@gnu.org>
> Date: Sun, 03 May 2020 13:20:09 -0400
> 
> A more efficient way to do this would be:
> 1) emacs-27: do something
> 2) emacs-27: revert something, and mark "do not merge to master"
> 
> Then no special handling is needed. 

Thanks, will keep this in mind.

Re: Procedure for reverting commits on release branch

[Glenn Morris]

A reminder about this issue, which happened again with recent AIX changes:

https://lists.gnu.org/r/emacs-devel/2020-05/msg00433.html

If a commit is made on the release branch, and then one wants to instead
have it only on master, then given the following commit sequence:

1) emacs-27: do something
2) emacs-27: revert something
3) master: do something

If gitmerge.el is now used to merge emacs-27 to master:
commit 1) is skipped, because it is already on master
commit 2) is merged

Net result: 3) is reverted on master and has to be applied again by hand.


A more efficient way to do this would be:
1) emacs-27: do something
2) emacs-27: revert something, and mark "do not merge to master"

Then no special handling is needed.