hg update: crossing branches vs. uncommitted changes.

[Douglas Philips]

Is there a philosophical reason in the Mercurial gestalt for using the  
-C option for both "wipe out uncommitted changes" and "yes, I really  
did mean to cross branches"?

I'd like to propose a new switch to update that says: "Yes, I meant to  
cross branches, and no, I did not mean to throw away uncommitted  
changes so please abort if I do have them."

I'm willing to submit the patch, but I was curious if there was a  
deeper reason I didn't grok about why the two cases were being merged.

I'd propose -B/--cross-branches as the new switch and leave -C exactly  
as it is now.
(I haven't worked up the revised help text or the updates to the test  
scripts.)

Thanks,
	-Doug