Re: SCMS question

On Fri, 2007-02-23 at 18:02 -0500, Tom Lane wrote:
> Yah know, the one bit of these pitches that always sounds like pure
> snake oil is the claim that they offer some kind of mechanical solution
> to merge conflicts.  AFAICS that has nothing to do with the SCMS in use
> and everything to do with whether your "diff" command is AI-complete.

Did you do any research to support that assertion? The nature and
quality of the merge algorithm used actually differs significantly
between SCMs. The ability to do history-sensitive merges actually
results in a significant reduction in the need for manual conflict
resolution. For one example among many, see the discussion around a new
proposed merge algorithm for Codeville:

http://lists.zooko.com/pipermail/revctrl/2005-May/000005.html
http://revctrl.org/PreciseCodevilleMerge

Or the "Mark Merge" algorithm used by Monotone:

http://monotone.ca/docs/Mark_002dMerge.html
http://revctrl.org/MarkMerge

Claiming that all this amounts to "snake oil" is plainly wrong, I think.

> I note also that CVS does have the ability to merge changes across
> branches, we just choose not to use it that way.

As far as I know, CVS does not provide a way to do a 3-way merge without
considerable manual effort (e.g. using a standalone tool to do the
actual merge).

-Neil