Re: When do we merge the commits from emacs-25 onto master?

[Eli Zaretskii <eliz@gnu.org>]

> Cc: bruce.connor.am@gmail.com, emacs-devel@gnu.org
> From: Paul Eggert <eggert@cs.ucla.edu>
> Date: Tue, 24 Nov 2015 11:46:11 -0800
> 
> > Would it work to somehow teach gitmerge.el to use the (fixed) text
> > from ChangeLog.2 as the merge-commit log message, instead of the
> > original log message at emacs-25 commit time?
> 
> A clever idea, and something like that might work, but it sounds 
> brittle. Often, changes to ChangeLog.2 aren't isolated to single 
> commits, and offhand I don't see how in general to figure out which 
> parts of ChangeLog.2 should be matched to which commits.

We shouldn't pay attention to _commits_ that change ChangeLog.2, we
should instead match Git log messages against entries in the
ChangeLog.2 the file in the working tree.

> How about the following idea instead.  Let's put the emacs-25 branch in 
> charge of ChangeLog.2, and put the master branch in charge of a new file 
> ChangeLog.3 that exists only in the master branch. We can do this by 
> updating CHANGELOG_HISTORY_INDEX_MAX to 3 only in the master.  Then 
> merges from emacs-25 to master should be trivial, as people who want to 
> manually edit ChangeLog.2 or to update it via 'make change-history' 
> should do so only in the emacs-25 branch. We'll need to modify 'make 
> ChangeLog' so that in the master it ignores commit messages merged from 
> the emacs-25 branch (I assume this is doable but I haven't checked 
> this). Backporting changes will still be a hassle (we'll need to run 
> 'make change-history' in the master, and then manually update 
> ChangeLog.3 to remove references to the changes being backported to 
> emacs-25), but that's OK.

You mean, "make change-history" on master will update ChangeLog.3 and
the same command on the branch will update ChangeLog.2?  But then how
to prevent the commit log messages from commits merged onto master
from appearing in ChangeLog.3?