vc-region-history promotion (was: removing white space highlight)

[Stefan Monnier <monnier@iro.umontreal.ca>]

> The question is what about the *VC annotated* file?  If I blame a
> particular section of a file how do I know who wrote that code and when?
> The problem is I can't tell because any particular check-in could be a
> whitespace change.  I'd actually have to start digging through older
> versions.

I agree such "unrelated changes" are generally undesired.
[ In the case of Emacs's own source code, we try to follow a policy where
people are allowed to "fix whitespace" but only in those places where
they're making other changes as well.  So a whose-file cleanup of
trailing whitespace is not accepted.  ]

This said, I recently stopped using vc-annotate and so don't care nearly
as much any more: instead I use vc-region-history, which gives me much
more detailed information where such whitespace games aren't very much
of a problem.  I'd been dreaming of a functionality like
vc-region-history ever since I started using TLA (i.e. before Bazaar
existed), and oddly enough so far only Git offers that feature, AFAIK.

vc-region-history also solves the problem of vc-annotate's blindness to
code removal (the vc-annotate output won't tell you where code was
removed, and even less by whom).


        Stefan