bug#20709: 25.0.50; anonymous functions in `auto-mode-alist'

bug#20709: 25.0.50; anonymous functions in `auto-mode-alist'

[Michael Heerdegen]

Hello,

the doc of `auto-mode-alist' doesn't say that the mode functions
specified must be named functions.  That's good IMO, since using
anonymous functions in the alist e.g. while let-binding it can sometimes
be useful.


But this is buggy.  Try this:

--8<---------------cut here---------------start------------->8---
;; -*- lexical-binding: t -*-

(setq auto-mode-alist
      `((".*" . ,(lambda ()
                   (emacs-lisp-mode)
                   'and-do-something-in-addition))))
--8<---------------cut here---------------end--------------->8---

Save it in a file, and load it (uncompiled) so that

  auto-mode-alist
   => ((".*" closure (t) nil (emacs-lisp-mode) (quote and-do-something-in-addition)))

Now open any file.  You get:

File mode specification error: (void-function closure)

The problem is these lines in the defun of `set-auto-mode' starting from
line 2871 in files.el:

--8<---------------cut here---------------start------------->8---
(if (and mode
         (consp mode)
         (cadr mode))
    (setq mode (car mode)
         ...
--8<---------------cut here---------------end--------------->8---

i.e., the value in the alist pair is not tested whether it is a
function, and the (REGEXP FUNCTION NON-NIL) case is assumed, which is
wrong.


Thanks,

Michael.




In GNU Emacs 25.0.50.4 (x86_64-unknown-linux-gnu, GTK+ Version 3.14.5)
 of 2015-05-30 on drachen
Windowing system distributor `The X.Org Foundation', version 11.0.11701000
System Description:	Debian GNU/Linux testing (stretch)

bug#20709: 25.0.50; anonymous functions in `auto-mode-alist'

[Stefan Monnier]

> File mode specification error: (void-function closure)

Plain bug, yes.  Please add a (not (functionp mode)) test in there.


        Stefan

bug#20709: 25.0.50; anonymous functions in `auto-mode-alist'

[Michael Heerdegen]

Stefan Monnier <monnier@iro.umontreal.ca> writes:

> > File mode specification error: (void-function closure)
>
> Plain bug, yes.  Please add a (not (functionp mode)) test in there.

Should I do it?  I have the rights now, but it'll be my first commit to
the emacs repo, so I'll have to read some stuff before to make sure I
make a commit confirming to the standards.

You don't need to answer, just expect a short delay.

Michael.

bug#20709: 25.0.50; anonymous functions in `auto-mode-alist'

[Stefan Monnier]

>> > File mode specification error: (void-function closure)
>> Plain bug, yes.  Please add a (not (functionp mode)) test in there.
> Should I do it?

Sure.

> I have the rights now, but it'll be my first commit to
> the emacs repo, so I'll have to read some stuff before to make sure I
> make a commit confirming to the standards.
> You don't need to answer, just expect a short delay.

No hurry,


        Stefan

bug#20709: 25.0.50; anonymous functions in `auto-mode-alist'

[Stefan Kangas]

Michael Heerdegen <michael_heerdegen@web.de> writes:

> Stefan Monnier <monnier@iro.umontreal.ca> writes:
>
>> > File mode specification error: (void-function closure)
>>
>> Plain bug, yes.  Please add a (not (functionp mode)) test in there.
>
> Should I do it?  I have the rights now, but it'll be my first commit to
> the emacs repo, so I'll have to read some stuff before to make sure I
> make a commit confirming to the standards.
>
> You don't need to answer, just expect a short delay.

Hi Michael,

Did you ever get around to fixing this?

Best regards,
Stefan Kangas

bug#20709: 25.0.50; anonymous functions in `auto-mode-alist'

[Michael Heerdegen]

Stefan Kangas <stefan@marxist.se> writes:

> Did you ever get around to fixing this?

I don't recall - probably not.  I will be absent for three days, I'll
have a look when I'm back.

Regards,

Michael.

bug#20709: 25.0.50; anonymous functions in `auto-mode-alist'

[Stefan Kangas]

Michael Heerdegen <michael_heerdegen@web.de> writes:

> Stefan Kangas <stefan@marxist.se> writes:
>
>> Did you ever get around to fixing this?
>
> I don't recall - probably not.  I will be absent for three days, I'll
> have a look when I'm back.

Just a reminder to please take a look at this when you find some time.

Thanks in advance.

Best regards,
Stefan Kangas

bug#20709: 25.0.50; anonymous functions in `auto-mode-alist'

[Lars Ingebrigtsen]

Michael Heerdegen <michael_heerdegen@web.de> writes:

> The problem is these lines in the defun of `set-auto-mode' starting from
> line 2871 in files.el:
>
> (if (and mode
>          (consp mode)
>          (cadr mode))
>     (setq mode (car mode)
>          ...
>
> i.e., the value in the alist pair is not tested whether it is a
> function, and the (REGEXP FUNCTION NON-NIL) case is assumed, which is
> wrong.

I've now fixed this in Emacs 29.

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