Subject: Re: bug#3566: 23.0.94; explain why not to use group defined by define-minor-mode

From: Lars Ingebrigtsen <[email-masked]>
Date: Wed, 27 Apr 2016 22:02:13 +0200

"Drew Adams" <[email-masked]> writes:

> In the Elisp manual and in the doc string for define-minor-mode, we
> are told not to use the custom group that is automatically defined for
> the mode variable, unless we have explicitly used defgroup to define
> the group.
>
> Why? Please provide some explanation.

This is the last change to that part:

 :group GROUP	Custom group name to use in all generated `defcustom' forms.
 		Defaults to MODE without the possible trailing \"-mode\".
-		(This default may not be a valid customization group defined
-		with `defgroup'.  Make sure it is.)
+		Don't use this default group name unless you have written a
+		`defgroup' to define that group properly.

The previous version may have been clearer?  I think what it's trying to
say is that if you have a :group, then you should make sure to add a
defgroup to that symbol.

> Why is it inadvisable to use the same generated group for other
> defcustoms without explicitly defining the group? What negative
> consequences arise if that is attempted? Please explain in the doc.

Presumably this is because there are things in a defgroup that should be
there, but aren't if you don't use a defgroup?  I.e., :link and a name
for the group.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no