Re: Unbalanced change hooks (part 2) [Documentation fix still remaining]

[Alan Mackenzie]

Hello, Eli.

On Wed, Aug 10, 2016 at 07:03:04PM +0300, Eli Zaretskii wrote:
> > From: Stefan Monnier <address@hidden>
> > Date: Wed, 10 Aug 2016 10:56:59 -0400

> > > AFAICT, this is what happens, indeed,
 
> > Then the old text was right: it's called before ANY modification.

> Convince Alan, and I will change it back.

For what it's worth, I don't like the vagueness of the doc as it
currently is, and I wouldn't be against changing it back _FOR 25.1_
We've got a bug, but it's not urgent enough to have to be fixed for
25.1.

> > > except that the call to before-change-functions in some cases does not
> > > precede the first modification of the series.  IOW, by the time the
> > > hook is called, some modifications were already done.

> > Sounds like a bug.

> I'm not convinced it's a bug.

> > In any case, my point is that the doc should still say "before any
> > modification" because that's really what the code *should* do.  We could
> > add a blurb in the doc saying that the before and after hooks may not be
> > properly paired (neither in number of calls nor in the specific value of
> > BEG/END), but we should still claim that they're both called for any and
> > all modifications

> Which is inaccurate when modifications are done in several separate
> parts, and you already agreed it's okay to call the hooks only once.
> So "for any and all modifications" is bound to draw fire from people
> who take that at face value.

Some while ago, I think you said that there is a systematic basis for
when before-change-functions doesn't get called.  Is that still your
view?  If so, let's document that system.  If not, then let's fix the
code so that it is systematic.

-- 
Alan Mackenzie (Nuremberg, Germany).