bug#32643: 26; minor-mode variables

[Drew Adams]

> Most probably, historical accidents.  But even finding that out is a
> non-trivial amount of work.

`auto-fill-mode' has already been identified. Let this bug report serve
(at least) to ask that Emacs set an `auto-fill-mode' mode variable.

> > (The bug report also asks whether it's a bug for a mode not to have
> > a variable, and suggests that it is. And if it's not, the report asks that
> > the Elisp manual give some guidance about when a mode should
> > not or need not have a variable.)
> 
> I think the manual already does what you want, it just doesn't say
> this is a bug (because it isn't, IMO).

The manual says nothing, AFAICT, that provides guidance about when
a mode should not or need not have a variable. Based on what it does
say, each mode "should" have a variable. Is that your point?

In that case, perhaps we should remove the text about some existing
modes not respecting this "should" - especially if that is only by
historical accident. Keeping the text suggests that there is some good
reason why some modes do not have variables.

And since a mode not having a variable is likely only an accident, 
presumably such a mode "should" be fixed, if identified.

Your point is presumably that there is no need to go searching for
such problems to fix, and it's not the end of the world if some such
modes exist. With that I agree.

Arguing about whether non-respect by Emacs code of some Emacs
convention is a "bug" is a bit like arguing about the number of
angels that can fit on a pinhead (poor Zippy!).

That's not the point of this bug report. I don't care whether you
call it a bug or "non-respect of the convention" or an enhancement
request.