overriding defaults (was Re: [PATCH] clone: update to branch ...)

[John Coomes]

Matt Mackall (mpm at selenic.com) wrote:
> On Wed, 2009-10-21 at 11:03 +0200, Adrian Buehlmann wrote:
> > On 21.10.2009 10:17, Peter Arrenbrecht wrote:
> > > On Wed, Oct 21, 2009 at 10:09 AM, Adrian Buehlmann <adrian at cadifra.com> wrote:
> > >> --source-branch sounds good
> > >>
> > >> (--source-branch could even be specified in [defaults], provided
> > >> mercurial would gracefully disregard it without moaning if it had
> > >> been specified for a non local source repo.)
> > >>
> > >> My plan for --source-branch was to do the same as
> > >>
> > >>  hg clone -u <branch of src's parent> src dest
> > >>
> > >> would do.
> > >>
> > >> That aside, we need 'clone -u' for completeness/versatility's sake.
> > >> We should implement that first and see if it has a chance to make
> > >> it into 1.4. Matt's messages seem to hint at that.
> > > 
> > > I guess `hg clone -u . src dest` should cover most scenarios where
> > > people would have wanted --source-branch.
> > >
> > 
> > Excellent.
> > 
> > So . is in scope. Neat.
> > 
> > Compare existing:
> > 
> > $ hg -R thg-stable par
> > changeset:   3536:cd50b769e235
> > branch:      stable
> > tag:         0.8.3
> > user:        Steve Borho <steve at borho.org>
> > date:        Tue Oct 06 22:07:28 2009 -0500
> > summary:     hgtk: correct arguments to dispatch() when launching qct
> > 
> > $ hg clone -r . thg-stable thg-stable-bug1234
> > requesting all changes
> > adding changesets
> > adding manifests
> > adding file changes
> > added 3537 changesets with 5456 changes to 522 files
> > updating to branch stable
> > 297 files updated, 0 files merged, 0 files removed, 0 files unresolved
> > 
> > Planned (faking output):
> > 
> > $ hg clone -u . thg-stable thg-stable-bug1235
> > updating to branch stable
> > 297 files updated, 0 files merged, 0 files removed, 0 files unresolved
> > 
> > > For folks who want to put "-u ." into [defaults], we should make sure
> > > that -U still disables it.
> > 
> > Good point.
> > 
> > -U should gracefully and silently override -u without mercurial moaning
> > at it (or at least not moan by default, i.e. without --verbose).
> 
> Disagree. Again, this is one of the fundamental problems with defaults:
> once you've set a default, there's no way to bypass it. Don't use 'em.

Or create a way to override them.  I think mercurial could really
benefit from an automatic way to allow bool options to be negated.
E.g., if every bool option foo implicitly defined an additional option
--no-foo.  ksh getopts supports this concept with -n/+n (ksh only
accepts short options, though).

Assuming it was/could be implemented, would something along those
lines be considered?

-John