[darcs-users] Re: .darcs is portable

[David Roundy]

On Wed, Mar 30, 2005 at 09:14:45PM -0400, zooko wrote:
> > I know that Schwern and maybe some others would prefer .darcs... I just
> > can't get why.
> 
> 3.  It's like what subversion does.  Really, I think the onus should be
> on the other side of the issue: why should the directory be named
> "_darcs" instad of ".darcs"?  I know of some answers, but none of them
> are very compelling answers.

The main reason why I chose _darcs instead of .darcs was because the
directory could potentially be very large.  I wasn't comfortable with the
idea of hiding what may be the single largest directory on your filesystem
(excluding its superdirectories).  To me, using .files to hide
configuration or metadata directories makes sense, but to hide a directory
that may contain hundreds of megabytes makes me uncomfortable.  Of course,
web browsers do it with their cache, but that annoys me.

There are a couple of penalties for allowing either naming scheme.  One is
the pain of going through all the code and adding checks before writing to
"_darcs/whatever".  A second is the user-interface issue of resolving the
ambiguity when both _darcs and .darcs are present--e.g. if you created a
repository with a new version of darcs having a .darcs directory, and then
created a second one using an older version of darcs, which creates a
_darcs directory.  A third issue is that while checking for both names is
no problem for local repositories, it's yet another round trip over
high-latency protocols, which isn't fun.  The second issue is complicated
by the fact possibilities of nested repositories, if you run with different
versions of darcs.  The fourth issue (which someone else already brought
up) is that we already have a ~/.darcs directory, which would probably need
to be renamed (with a check, perhaps, for a legacy ~/.darcs directory to
smooth the transition).

On the whole, there doesn't seem to me to be a compelling reason to hide
_darcs.  The fact that subversion does it that way seems irrelevant.
Subversion doesn't store the entire repository history in its hidden
directories.
-- 
David Roundy