bug#9591: 24.0.50; buffer name completion

[Eli Zaretskii <eliz@gnu.org>]

> From: Stefan Monnier <monnier@iro.umontreal.ca>
> Date: Thu, 29 Sep 2011 18:02:25 -0400
> Cc: rms@gnu.org, 9591@debbugs.gnu.org
> 
> Having looked a bit more into it, I'm undecided:
> we could go like you suggest and force users to type a leading space,
> but at least for my own use this would be inconvenient, since I pretty
> often need to get at hidden buffers, and often don't know the exact name
> of the buffer I want (and I don't even always know whether it's a hidden
> buffer or not, since Elisp authors aren't always very consistent about
> it).  So I find it very handy to just say "C-x b *foo TAB" (or indeed
> just "C-x b foo TAB" in Emacs-24) and see all buffers that contain
> "foo", regardless of whether they're hidden or not.
> So it seems that both behaviors are desirable and I'm not sure how to
> tell which to use when.

There's what Lars suggested, which sounds like it can cater to both
use cases.

Failing that, add some non-default completion style which behaves like
you want.  I hope _you_ have no problems with customizing for
non-default behavior ;-)

> confirm-nonexistent-file-or-buffer already found resistance when
> I introduced it

I don't understand the resistance: that feature saved my a$$ a few
times, when my fingers were faster than my brain.