I’ve found synchronization across the network to be somewhat faster than Arch, and of course on a local disk, it is quite fast.

The Darcs wiki is a great resource, and has a page listing several options for Emacs, including both VC integration and standalone tools.

You say commits are very fast. What about synchronization between repositories, is that also fast? And does DARCS have an emacs frontend similar to the one for CVS?

In the time I’ve been using darcs, I’ve found it handles conflicts quite well — about as well as tla or Subversion.

The one case where it seems to have trouble is if there are patches that independently add files or directories with the same name. (I mean new files show up independently, with differently-named patches, in the trees that are to be merged.) David is aware of that issue, but it is really quite rare in practice. In fact, it generally shows up when you try to merge trees that don’t share a common ancestor, an operation that no revision control system does a very good job at, IMHO.

Anyway, you can pretty easily see what darcs will do with a basic test. Here’s what I did:


~/tree/t$ darcs get ../sgml-common sgml-common1
Copying patch 25 of 25... done!
Finished getting.
/tree/t$ darcs get ../sgml-common sgml-common2
Copying patch 25 of 25... done!
Finished getting.
~/tree/t$ cd sgml-common1/sgml-common
~/tree/t/sgml-common1/sgml-common$ emacs SConstruct
~/tree/t/sgml-common1/sgml-common$ darcs record -am 'Test commit 1'
Finished recording patch 'Test commit 1'
~/tree/t/sgml-common1/sgml-common$ cd ../../sgml-common2/sgml-common
~/tree/t/sgml-common2/sgml-common$ vim SConstruct
~/tree/t/sgml-common2/sgml-common$ darcs record -am 'Test commit 2'
Finished recording patch 'Test commit 2'
~/tree/t/sgml-common2/sgml-common$ darcs pull -a ~/tree/t/sgml-common1
We have conflicts in the following files:
./sgml-common/SConstruct
Finished pulling.
jgoerzen@katherina:~/tree/t/sgml-common2/sgml-common$ head SConstruct
# vim: set filetype=python :
from glob import glob
v v v v v v v
import os, re, ConfigParser
*************
import re, os
^ ^ ^ ^ ^ ^ ^


So, it highlighed the conflicting section in the file in much the same way as other version control systems would. darcs pull also has an --external-merge command so you can use some other tool to merge conflicts. There are examples of using Emacs and kdiff3, opendiff, or xxdiff as an external merge command.