Re: vc-diff in non-VC buffer

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

> So, for example, you can go to a top-level project directory and just
> do C-x v = to look at the state of all changes beneath it, regardless
> of whether you're actually visiting a controlled file.  This is useful,
> and I think many VC users would be (rightly) annoyed if they lost it.

I don't know of such a feature, so I doubt many users would "miss it".

The above scenario to me has the following problem: when you say "go to
a top-level project directory", this can mean to do it by opening some
arbitrary file in that top-level dir or by opening the dir with dired or
with vc-dired.

Of those 3 cases, I think the first case should not be supported.  C-v x =
from a file buffer should only apply to that file.  The third should of
course be supported and the one I expect people to use.

The second doesn't matter: if it works, it's harmless and if it doesn't it's
not serious either because the user could have used vc-dired instead.
But it should only work if the corresponding dir is under some kind of
version control, of course.

> I'm testing code that errors out if you (a) have an empty fileset, and
> (b) no files are registered immediately under default-directory.  Juanma
> thinks this will cover his use case.

Don't check files: it should work in a BACKEND-controlled directory even if no
files are currently registered in BACKEND yet.  Check `responsible-p' or
something like that (applied to the directory) instead.


        Stefan