[rfc] 'bzr missing' for checkout could use master branch for comparing histories

[Martin Pool]

On  1 Aug 2006, Alexander Belchenko <bialix at ukr.net> wrote:
> IIRC, in CVS 'update -n' show list of files that will be updated. Not 
> revisions log.
> 
> What about syntax: 'bzr missing --master' ?
> It's will be clear enough to specify that user want to inspect 
> difference with master branch, not with pull location.

+1 on the general concept of being able to find out what needs to be
brought in from the master branch.

I think missing has some problems as it currently exists.  We should
think about them before adding more features.  

I find I almost always want to just know about the revisions on one
side (either --mine or --theirs).  The current default of showing both
makes it just hard to read the output.  Missing pretty much corresponds
to a preview of what will be done by push or pull or merge, and wanting
additional behaviour corresponding to update just makes that resemblance
stronger.

Rather than duplicate all these cases in 'missing' options I think we
should just put them in the corresponding commands, as Erik suggested
for 'update -n'.  However I think we can refine this into several
different options

 --verbose, -v 	    show which files will be changed
 --list, -l         show a list of revisions to be applied
 --dry-run, -n      just show what would be done

Then 'update -ln' should give the desired result.  This has the good
side effect that 'update -l' will often be interesting in its own right.

One risk with this is that people may omit '-n' and update when they
don't want to.  I think it's a tolerable risk, and no unrecoverable data
is lost.

-- 
Martin