diff-mode-hook (was Re: minor bug in next-error-follow-minor-mode?)

[Bruce Stephens <bruce@cenderis.demon.co.uk>]

Dan Nicolaescu <dann@ics.uci.edu> writes:

> Bruce Stephens <bruce@cenderis.demon.co.uk> writes:

[...]

>   > and indeed found that C-c C-f switched it off (and another C-c C-f
>   > switched it on).  However, now I look at the code, I think it's just a
>   > minor bug, where ":init-value" ought to be ":lighter", in simple.el.
>   > (" Fol" is presumably a valid non-nil value, but it looks suspiciously
>   > like something meant for the modeline.)
>
> You are right, I fixed this.

Yes, I just noticed.  Thanks for that.

While investigating that, I tried switching on
next-error-follow-minor-mode explicitly:

(add-hook 'diff-mode-hook (function () (next-error-follow-minor-mode t)))

But that failed, and then I tried a function that did (setq foo 42),
and that didn't seem to set foo.  

I suspect diff-mode doesn't call diff-mode-hook.  The documentation
for diff-mode doesn't say it does, but diff-mode-hook does suggest it
gets called.  So something seems wrong.