Re: Messing with the VC history

[David Kastrup <dak@gnu.org>]

"Stephen J. Turnbull" <stephen@xemacs.org> writes:

> [1]  However, some people think a mainline with only merge commits on
> it is pretty, and they just oppose rebasing on principle.

"Beauty" as an underlying concept of "pretty" usually involves
perfection, and perfection in technical settings implies everything
having a purpose.  A merge commit is a branch that starts off somewhere
and ends somewhere.  If there is no point to where the branch starts
off, the branch start is ugly, never mind whether you consider a merge
in itself pretty.

An example for a merge commit in a pretty-based development environment
would be
<URL:https://code.google.com/p/lilypond/issues/detail?id=4097#c14>.  A
merge commit is used because not all intermediate states in the
logically separate commits may be compilable (either they are known to
be uncompilable, or the jury is out on them).

Even through the commit sequence itself has been "prettified" by
structuring it into separate commits doing one logical task, a merge
commit is warranted in order not to cause bisection problems.  The
starting point of the branching point is not arbitrary: it is the parent
of the merge commit.  Such an incestuous merge has to be ordered
explicitly using the --no-ff flag to merge.

-- 
David Kastrup