bug#11482: 24.0.96; Keep `M-s' as a prefix key for search (conflict with Gnus)

[Drew Adams <drew.adams@oracle.com>]

> > Feel free to close this bug, if you don't care that Gnus respects the `M-s'
> > "convention" and #1 is most important. I filed the bug report based on an
> > Icicles user report. I filed it because of my understanding that `M-s' is
> > conventionally a search prefix key.
> 
> Let's change the topic of this bug then, to be about whether M-s should be a
> reserved key to be respected by all modes or not, and therefore require an
> update to the Elisp convention. Lars, do you think this would be troublesome
> for Gnus?

I'm not sure I'd advise that.  I think it might be better to leave
this `M-s' "rule" as it is, and thus leave uses by Emacs itself up to
Emacs Dev.

Users and 3rd-party library authors already understand, or will come
to understand, that Emacs itself uses `M-s' as a prefix for search keys,
and they will take that into account in deciding whether they want to
repurpose it.

IOW, if it is not cast in bronze in the `Key Binding Conventions' then
there is more leeway for judgment calls, case by case.  That might be
the best approach for this.  The list of official key reservations is
purposely quite limited, and that has not hurt Emacs.

And there will likely be other such decisions, as Emacs makes more
use of prefix keys (because keys are a limited resource).  That's my
expectation, at least: consolidation of related keys on prefix keys
(by default), such as was done for `M-s', in order to deal with a
shortage of keys.

In any case, IMHO, a decision whether to make `M-s' reserved should
not be based on, or even influenced by, whether doing that would be
troublesome for Gnus.

Reserving `M-s' is a bigger decision - even if it would not be
troublesome for Gnus, that should not be sufficient to decide to do
it.  And even if it is troublesome for Gnus, that should not be
sufficient to decide not to do it.

So I would prefer to see this bug dealt with, one way or another,
without deciding once and for all whether `M-s' should be reserved
per the published key-binding conventions.

Just one opinion (and I could be persuaded otherwise).