GNU bug report logs - #43037
Eval error in the ‘c-lang-defvar’ or ‘c-lang-setvar’

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: AC <achirvasub <at> gmail.com>
To: emacs-bugs <bug-gnu-emacs <at> gnu.org>
Subject: Eval error in the ‘c-lang-defvar’ or ‘c-lang-setvar’
Date: Tue, 25 Aug 2020 08:37:39 -0400

I compile emacs off the emacs-27 branch. On those machines, opening certain file types results in the above error.

For .js files for instance, the full error is 

Eval error in the ‘c-lang-defvar’ or ‘c-lang-setvar’ for ‘font-lock-comment-end-skip’ (fallback source eval - js-mode compiled with CC Mode 5.34 but loaded with 5.34.1): (error "‘c-font-lock-comment-end-skip’ got no (prior) value in js-mode (might be a cyclic reference)")

Message #8 received at 43037 <at> debbugs.gnu.org (full text, mbox):

From: Lars Ingebrigtsen <larsi <at> gnus.org>
To: AC <achirvasub <at> gmail.com>
Cc: 43037 <at> debbugs.gnu.org
Subject: Re: bug#43037: Eval error in the ‘c-lang-defvar’ or ‘c-lang-setvar’
Date: Fri, 16 Oct 2020 10:29:18 +0200

AC <achirvasub <at> gmail.com> writes:

> I compile emacs off the emacs-27 branch. On those machines, opening
> certain file types results in the above error.
>
> For .js files for instance, the full error is 
>
> Eval error in the ‘c-lang-defvar’ or ‘c-lang-setvar’ for
> ‘font-lock-comment-end-skip’ (fallback source eval - js-mode compiled
> with CC Mode 5.34 but loaded with 5.34.1): (error
> "‘c-font-lock-comment-end-skip’ got no (prior) value in js-mode (might
> be a cyclic reference)")

(This bug report unfortunately got no attention at the time.)

I'm unable to reproduce this bug in Emacs 27 or Emacs 28.  Do you have a
recipe for reproducing this bug, starting from "emacs -Q"?

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

Message #13 received at 43037 <at> debbugs.gnu.org (full text, mbox):

From: AC <achirvasub <at> gmail.com>
To: Lars Ingebrigtsen <larsi <at> gnus.org>
Cc: 43037 <at> debbugs.gnu.org
Subject: Re: bug#43037: Eval error in the ‘c-lang-defvar’ or ‘c-lang-setvar’
Date: Fri, 16 Oct 2020 06:14:17 -0400

On October 16, 2020 4:29:18 AM EDT, Lars Ingebrigtsen <larsi <at> gnus.org> wrote:
>AC <achirvasub <at> gmail.com> writes:
>
>> I compile emacs off the emacs-27 branch. On those machines, opening
>> certain file types results in the above error.
>>
>> For .js files for instance, the full error is 
>>
>> Eval error in the ‘c-lang-defvar’ or ‘c-lang-setvar’ for
>> ‘font-lock-comment-end-skip’ (fallback source eval - js-mode compiled
>> with CC Mode 5.34 but loaded with 5.34.1): (error
>> "‘c-font-lock-comment-end-skip’ got no (prior) value in js-mode
>(might
>> be a cyclic reference)")
>
>(This bug report unfortunately got no attention at the time.)
>
>I'm unable to reproduce this bug in Emacs 27 or Emacs 28.  Do you have
>a
>recipe for reproducing this bug, starting from "emacs -Q"?
>

Yes. 

Literally seconds ago I compiled emacs-27, started it up with 'emacs -Q' and then visited the blank file '~/new.js'. That error popped up.

Message #16 received at 43037 <at> debbugs.gnu.org (full text, mbox):

From: Eli Zaretskii <eliz <at> gnu.org>
To: AC <achirvasub <at> gmail.com>, Alan Mackenzie <acm <at> muc.de>
Cc: larsi <at> gnus.org, 43037 <at> debbugs.gnu.org
Subject: Re: bug#43037: Eval error in the
 ‘c-lang-defvar’ or
 ‘c-lang-setvar’
Date: Fri, 16 Oct 2020 13:45:34 +0300

> Date: Fri, 16 Oct 2020 06:14:17 -0400
> From: AC <achirvasub <at> gmail.com>
> Cc: 43037 <at> debbugs.gnu.org
> 
> Literally seconds ago I compiled emacs-27, started it up with 'emacs -Q' and then visited the blank file '~/new.js'. That error popped up.

I cannot reproduce this with stock Emacs 27.1, but I can reproduce
with the current emacs-27 branch.  The more detailed error message is
this:

  Eval error in the ‘c-lang-defvar’ or ‘c-lang-setvar’ for ‘font-lock-comment-end-skip’ (fallback source eval - js-mode compiled with CC Mode 5.34 but loaded with 5.34.1): (error "‘c-font-lock-comment-end-skip’ got no (prior) value in js-mode (might be a cyclic reference)")

Alan, can you take a look, please?

Message #19 received at 43037 <at> debbugs.gnu.org (full text, mbox):

From: AC <achirvasub <at> gmail.com>
To: Eli Zaretskii <eliz <at> gnu.org>,Alan Mackenzie <acm <at> muc.de>
Cc: larsi <at> gnus.org, 43037 <at> debbugs.gnu.org
Subject: Re: bug#43037: Eval error in the ‘c-lang-defvar’ or ‘c-lang-setvar’
Date: Fri, 16 Oct 2020 09:35:50 -0400

Thank you for confirming it happens!

Some additional info: I can reproduce this consistently on 3 machines, all running Ubuntu (20.04 and 18.04); the procedure is the same on all of them (compile the current emacs-27 branch from the repo). I don't know if this (the Ubuntu base) matters..

On the other hand, the "standard" Emacs 27.1 that comes with Arch Linux does not exhibit this.

On October 16, 2020 6:45:34 AM EDT, Eli Zaretskii <eliz <at> gnu.org> wrote:
>> Date: Fri, 16 Oct 2020 06:14:17 -0400
>> From: AC <achirvasub <at> gmail.com>
>> Cc: 43037 <at> debbugs.gnu.org
>> 
>> Literally seconds ago I compiled emacs-27, started it up with 'emacs
>-Q' and then visited the blank file '~/new.js'. That error popped up.
>
>I cannot reproduce this with stock Emacs 27.1, but I can reproduce
>with the current emacs-27 branch.  The more detailed error message is
>this:
>
>Eval error in the ‘c-lang-defvar’ or ‘c-lang-setvar’ for
>‘font-lock-comment-end-skip’ (fallback source eval - js-mode compiled
>with CC Mode 5.34 but loaded with 5.34.1): (error
>"‘c-font-lock-comment-end-skip’ got no (prior) value in js-mode (might
>be a cyclic reference)")
>
>Alan, can you take a look, please?

Message #22 received at 43037 <at> debbugs.gnu.org (full text, mbox):

From: Alan Mackenzie <acm <at> muc.de>
To: Eli Zaretskii <eliz <at> gnu.org>
Cc: larsi <at> gnus.org, AC <achirvasub <at> gmail.com>, 43037 <at> debbugs.gnu.org
Subject: Re: bug#43037: Eval error in the ‘c-lang-defvar’ or ‘c-lang-setvar’
Date: Fri, 16 Oct 2020 14:43:53 +0000

Hello, Eli and AC.

On Fri, Oct 16, 2020 at 13:45:34 +0300, Eli Zaretskii wrote:
> > Date: Fri, 16 Oct 2020 06:14:17 -0400
> > From: AC <achirvasub <at> gmail.com>
> > Cc: 43037 <at> debbugs.gnu.org

> > Literally seconds ago I compiled emacs-27, started it up with 'emacs
> > -Q' and then visited the blank file '~/new.js'. That error popped
> > up.

> I cannot reproduce this with stock Emacs 27.1, but I can reproduce
> with the current emacs-27 branch.  The more detailed error message is
> this:

>   Eval error in the ‘c-lang-defvar’ or ‘c-lang-setvar’ for
>   ‘font-lock-comment-end-skip’ (fallback source eval - js-mode
>   compiled with CC Mode 5.34 but loaded with 5.34.1): (error
>   "‘c-font-lock-comment-end-skip’ got no (prior) value in js-mode
>   (might be a cyclic reference)")

> Alan, can you take a look, please?

Yes, I think the problem is precisely what the error message said.
js-mode.el was compiled (quite a long time ago) when c-version was still
5.34, but since then c-version has become 5.34.1.  So their is a clash
between what js-mode.el was compiled with and the CC Mode current in the
Emacs version.

To resolve this, I think deleting lisp/progmodes/js-mode.elc and
compiling lisp/progmodes/js-mode.el again should sort out the problem.

This problem has happened more than once.  I think the solution should
be in the Makefile to add a dependency of js-mode.elc on cc-defs.el.

-- 
Alan Mackenzie (Nuremberg, Germany).

Message #25 received at 43037 <at> debbugs.gnu.org (full text, mbox):

From: AC <achirvasub <at> gmail.com>
To: Alan Mackenzie <acm <at> muc.de>,Eli Zaretskii <eliz <at> gnu.org>
Cc: larsi <at> gnus.org, 43037 <at> debbugs.gnu.org
Subject: Re: bug#43037: Eval error in the ‘c-lang-defvar’ or ‘c-lang-setvar’
Date: Fri, 16 Oct 2020 11:38:28 -0400

Thank you!

Quick request for clarification:

On October 16, 2020 10:43:53 AM EDT, Alan Mackenzie <acm <at> muc.de> wrote:
>Hello, Eli and AC.
>
>On Fri, Oct 16, 2020 at 13:45:34 +0300, Eli 
>Yes, I think the problem is precisely what the error message said.
>js-mode.el was compiled (quite a long time ago) when c-version was
>still
>5.34, but since then c-version has become 5.34.1.  So their is a clash
>between what js-mode.el was compiled with and the CC Mode current in
>the
>Emacs version.
>
>To resolve this, I think deleting lisp/progmodes/js-mode.elc and
>compiling lisp/progmodes/js-mode.el again should sort out the problem.
>

Were all instances of 'js-mode' in the above-quoted message meant to be 'js' instead?

I have js.{el,elc} in my clone of the repo, but no js-mode* at all (anywhere in my homedir, for that matter).

Message #28 received at 43037 <at> debbugs.gnu.org (full text, mbox):

From: Eli Zaretskii <eliz <at> gnu.org>
To: Alan Mackenzie <acm <at> muc.de>
Cc: larsi <at> gnus.org, achirvasub <at> gmail.com, 43037 <at> debbugs.gnu.org
Subject: Re: bug#43037: Eval error in the ‘c-lang-defvar’ or ‘c-lang-setvar’
Date: Fri, 16 Oct 2020 18:45:43 +0300

> Date: Fri, 16 Oct 2020 14:43:53 +0000
> Cc: AC <achirvasub <at> gmail.com>, larsi <at> gnus.org, 43037 <at> debbugs.gnu.org
> From: Alan Mackenzie <acm <at> muc.de>
> 
> >   Eval error in the ‘c-lang-defvar’ or ‘c-lang-setvar’ for
> >   ‘font-lock-comment-end-skip’ (fallback source eval - js-mode
> >   compiled with CC Mode 5.34 but loaded with 5.34.1): (error
> >   "‘c-font-lock-comment-end-skip’ got no (prior) value in js-mode
> >   (might be a cyclic reference)")
> 
> > Alan, can you take a look, please?
> 
> Yes, I think the problem is precisely what the error message said.
> js-mode.el was compiled (quite a long time ago) when c-version was still
> 5.34, but since then c-version has become 5.34.1.  So their is a clash
> between what js-mode.el was compiled with and the CC Mode current in the
> Emacs version.
> 
> To resolve this, I think deleting lisp/progmodes/js-mode.elc and
> compiling lisp/progmodes/js-mode.el again should sort out the problem.

You are right.

> This problem has happened more than once.  I think the solution should
> be in the Makefile to add a dependency of js-mode.elc on cc-defs.el.

Yes, please.  On the emacs-27 branch, please.

Thanks.

Message #31 received at 43037 <at> debbugs.gnu.org (full text, mbox):

From: Alan Mackenzie <acm <at> muc.de>
To: AC <achirvasub <at> gmail.com>
Cc: Eli Zaretskii <eliz <at> gnu.org>, 43037 <at> debbugs.gnu.org, larsi <at> gnus.org
Subject: Re: bug#43037: Eval error in the ‘c-lang-defvar’ or ‘c-lang-setvar’
Date: Fri, 16 Oct 2020 16:04:06 +0000

Hello, AC.

On Fri, Oct 16, 2020 at 11:38:28 -0400, AC wrote:
> Thank you!

> Quick request for clarification:

> On October 16, 2020 10:43:53 AM EDT, Alan Mackenzie <acm <at> muc.de> wrote:
> >Hello, Eli and AC.

> >On Fri, Oct 16, 2020 at 13:45:34 +0300, Eli 
> >Yes, I think the problem is precisely what the error message said.
> >js-mode.el was compiled (quite a long time ago) when c-version was
> >still
> >5.34, but since then c-version has become 5.34.1.  So their is a clash
> >between what js-mode.el was compiled with and the CC Mode current in
> >the
> >Emacs version.

> >To resolve this, I think deleting lisp/progmodes/js-mode.elc and
> >compiling lisp/progmodes/js-mode.el again should sort out the problem.


> Were all instances of 'js-mode' in the above-quoted message meant to be 'js' instead?

Apologies.  js-mode should indeed have been js, as in js.el and js.elc.

> I have js.{el,elc} in my clone of the repo, but no js-mode* at all (anywhere in my homedir, for that matter).

-- 
Alan Mackenzie (Nuremberg, Germany).

Message #34 received at 43037 <at> debbugs.gnu.org (full text, mbox):

From: AC <achirvasub <at> gmail.com>
To: Alan Mackenzie <acm <at> muc.de>
Cc: Eli Zaretskii <eliz <at> gnu.org>, 43037 <at> debbugs.gnu.org, larsi <at> gnus.org
Subject: Re: bug#43037: Eval error in the ‘c-lang-defvar’ or ‘c-lang-setvar’
Date: Fri, 16 Oct 2020 12:08:28 -0400

On October 16, 2020 12:04:06 PM EDT, Alan Mackenzie <acm <at> muc.de> wrote:
>
>> Were all instances of 'js-mode' in the above-quoted message meant to
>be 'js' instead?
>
>Apologies.  js-mode should indeed have been js, as in js.el and js.elc.
>

Thank you!

I can confirm your suggestion works fine: simply touching lisp/progmodes/js.el to change its timestamp induced the build system to recompile it, and now the error's gone.

Message #37 received at 43037 <at> debbugs.gnu.org (full text, mbox):

From: Alan Mackenzie <acm <at> muc.de>
To: Eli Zaretskii <eliz <at> gnu.org>
Cc: larsi <at> gnus.org, achirvasub <at> gmail.com, 43037 <at> debbugs.gnu.org
Subject: Re: bug#43037: Eval error in the ‘c-lang-defvar’ or ‘c-lang-setvar’
Date: Fri, 16 Oct 2020 16:32:55 +0000

Hello, Eli.

On Fri, Oct 16, 2020 at 18:45:43 +0300, Eli Zaretskii wrote:
> > Date: Fri, 16 Oct 2020 14:43:53 +0000
> > Cc: AC <achirvasub <at> gmail.com>, larsi <at> gnus.org, 43037 <at> debbugs.gnu.org
> > From: Alan Mackenzie <acm <at> muc.de>

[ .... ]

> > To resolve this, I think deleting lisp/progmodes/js-mode.elc and
> > compiling lisp/progmodes/js-mode.el again should sort out the problem.

> You are right.

> > This problem has happened more than once.  I think the solution should
> > be in the Makefile to add a dependency of js-mode.elc on cc-defs.el.

> Yes, please.  On the emacs-27 branch, please.

DONE.

> Thanks.

-- 
Alan Mackenzie (Nuremberg, Germany).

Message #42 received at 43037-done <at> debbugs.gnu.org (full text, mbox):

From: Alan Mackenzie <acm <at> muc.de>
To: AC <achirvasub <at> gmail.com>
Cc: Eli Zaretskii <eliz <at> gnu.org>, 43037-done <at> debbugs.gnu.org, larsi <at> gnus.org
Subject: Re: bug#43037: Eval error in the ‘c-lang-defvar’ or ‘c-lang-setvar’
Date: Fri, 16 Oct 2020 20:04:20 +0000

Hello, AC.

On Fri, Oct 16, 2020 at 12:08:28 -0400, AC wrote:


> On October 16, 2020 12:04:06 PM EDT, Alan Mackenzie <acm <at> muc.de> wrote:

> >> Were all instances of 'js-mode' in the above-quoted message meant
> >> to be 'js' instead?

> >Apologies.  js-mode should indeed have been js, as in js.el and js.elc.


> Thank you!

> I can confirm your suggestion works fine: simply touching
> lisp/progmodes/js.el to change its timestamp induced the build system
> to recompile it, and now the error's gone.

That's great!  I've put the amendment into the emacs-27 branch
Makefile.in, as discussed with Eli, so I'm closing the bug with this
post.

-- 
Alan Mackenzie (Nuremberg, Germany).

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