Re: xref and leaving "temporary" buffers open

[Dmitry Gutov]

On 07/27/2015 08:34 PM, Nix wrote:

> FWIW, there are existing packages which automatically kill buffers that
> weren't modified for a certain period of time and are no longer
> displayed in any frame (using the buffer-modified-tick). If you combine
> that with a modification such that the comparatively limited set of
> commands that explicitly open buffers on user request set a buffer-local
> 'persistent-buffer' variable in them, you can then arrange to
> automatically erase all non-persistent buffers without touching the
> packages that open such buffers.

I think we'd rather move into the direction of other packages using the 
"hidden buffers" facility, thus indicating that their buffers can 
actually be cleaned up.

Cleaning those up will cause issues already: I'm sure someone, somewhere 
will use find-file-hidden, don't mark the returned buffer as persistent, 
save a reference to it, and then try to use it later.

> (However, this would tend to break
> third-party modes that open lots of extra buffers -- but how many of
> those are there? It's mostly things, like Gnus, that implement whole
> multi-buffer applications inside Emacs, I think. There seem to be
> arguments in favour both of the local variable to mark temporariness and
> the local variable to mark *non*-temporariness...)

A variable to mark temporariness might help a lot, actually. As long as 
it very obvious to the caller, so that we don't end up with heaps of 
hidden buffers, without any of them marked as temporary.