bug#15746: 24.3; [PATCH] bookmark should confirm when overwrite

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

> I think most users would expect that that *interactively* setting a
> bookmark would confirm when overriding a previous bookmark of the
> same name, instead of just silently overwriting it.

There are plenty of use cases where you want to silently *update* an
existing bookmark, e.g., update its location.

That's the point of `bookmark-set': it both creates and updates.

> Drew might be right that `bookmark-set' should not include this
> functionality itself, but then there should be a wrapper function,
> and every interactive key (C-x r m) currently default bound to
> `bookmark-set' should be instead set to that wrapper function, then.
> IOW, that question is just a matter of internal code orgainzation,
> not of user-visible functionality.

That effectively just *replaces* interactive use of `bookmark-set'
with the proposed alternative behavior.  That is exactly what I
object to.

I do not object to adding a different command, and either not binding
it by default (users can choose to do that) or binding it to a
different key.  That lets users choose the behavior they want, and
if they for some reason want there to be only one of the behaviors
then they can easily bind both keys to the same command or unbind a
key.

And I do not object to adding a user option that thus conditionally
changes the behavior of `bookmark-set'.

The first approach of these two alternatives gives the most
flexibility.  With it, they need not choose the behavior once and for
all but can instead just choose which behavior they want to invoke
in any given context.

My point is that it is a mistake to think there is only one interactive
use of `bookmark-set' and that for that one use users would want to be
queried wrt overwriting.

There are lots of kinds of bookmarks, and lots of different uses of
bookmarks.  And some of those call precisely for silently updating an
existing bookmark.