Re: Merging emacs-23 into trunk

["Stephen J. Turnbull" <stephen@xemacs.org>]

Eli Zaretskii writes:
 > > From: "Stephen J. Turnbull" <stephen@xemacs.org>
 > > Date: Wed, 10 Nov 2010 14:44:49 +0900
 > > Cc: Stefan Monnier <monnier@IRO.UMontreal.CA>, emacs-devel@gnu.org
 > > 
 > > Glenn Morris writes:
 > > 
 > >  > Can you make it just skip merging configure altogether?
 > > 
 > > Not really.  That's inherent in the philosophy of atomic commits and
 > > DAG-based merging.
 > 
 > I don't follow.  Do you have in mind a revision where configure was
 > committed together with other files?  If so, I understand.  But if it
 > was committed alone, what is the issue with atomic commits?

The words "philosophy" and "and" in my statement are crucial.  Of
course we've learned how to split an atom.  But then it's not an atom
any more.  Similarly, if you are going to commit changes to a
generated file, then it should be committed with the source changes
that generate them.

The DAG-based merging helps to enforce this because there's no way
that the VCS can determine that these changes are related via
syntactic analysis, and humans won't always get it right.  So DAG-
based merging takes branch history as the proxy for relatedness.
That's why workflows are so important.  If you want a "better" notion
of relatedness, use Darcs, which is designed to be more or less
workflow-free (but in practice doesn't achieve that yet).

The fact that Bazaar doesn't handle the situation very well is quite
apart from the design philosophy.