GNU bug report logs - #78818
31.0.50; Missing lexical-binding cookies when compiling trampolines

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

From: Daniel Mendler <mail <at> daniel-mendler.de>
To: bug-gnu-emacs <at> gnu.org
Subject: 31.0.50; Missing lexical-binding cookies when compiling trampolines
Date: Tue, 17 Jun 2025 20:38:20 +0200

In the *Native-compile-Log* I see the following messages on a newly
compiled Emacs 31 from the current Emacs master branch:

Warning (files): Missing ‘lexical-binding’ cookie in "/tmp/emacs-int-comp-subr--trampoline-72756e2d686f6f6b73_run_hooks_0-ZQkOM2.el".
You can add one with ‘M-x elisp-enable-lexical-binding RET’.
See ‘(elisp)Selecting Lisp Dialect’ and ‘(elisp)Converting to Lexical Binding’
for more information.
Compiling $HOME/.config/emacs/eln-cache/31.0.50-45ab2aa9/subr--trampoline-72756e2d686f6f6b73_run_hooks_0.eln...

In GNU Emacs 31.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version
 3.24.49, cairo version 1.18.4) of 2025-06-17 built on host
Windowing system distributor 'The X.Org Foundation', version 11.0.12101016
System Description: Debian GNU/Linux 13 (trixie)

Configured using:
 'configure --prefix=$HOME/.local/share/emacs
 --without-compress-install --with-tree-sitter --with-native-compilation
 --with-dbus --without-selinux --without-threads --disable-gc-mark-trace
 --without-gsettings --without-gpm --with-cairo --with-cairo-xcb
 --with-xinput2 --with-x-toolkit=gtk3 --without-toolkit-scroll-bars'

Configured features:
CAIRO DBUS FREETYPE GIF GLIB GMP GNUTLS HARFBUZZ JPEG LIBOTF LIBSYSTEMD
LIBXML2 MODULES NATIVE_COMP NOTIFY INOTIFY PDUMPER PNG RSVG SECCOMP
SOUND SQLITE3 TIFF TREE_SITTER WEBP X11 XDBE XIM XINERAMA XINPUT2 XPM
XRANDR GTK3 ZLIB

Important settings:
  value of $LANG: en_US.UTF-8
  locale-coding-system: utf-8-unix

Major mode: LIMPLE

Message #8 received at 78818 <at> debbugs.gnu.org (full text, mbox):

From: Eli Zaretskii <eliz <at> gnu.org>
To: Daniel Mendler <mail <at> daniel-mendler.de>
Cc: 78818 <at> debbugs.gnu.org
Subject: Re: bug#78818: 31.0.50;
 Missing lexical-binding cookies when compiling trampolines
Date: Wed, 18 Jun 2025 14:41:30 +0300

> Date: Tue, 17 Jun 2025 20:38:20 +0200
> From:  Daniel Mendler via "Bug reports for GNU Emacs,
>  the Swiss army knife of text editors" <bug-gnu-emacs <at> gnu.org>
> 
> In the *Native-compile-Log* I see the following messages on a newly
> compiled Emacs 31 from the current Emacs master branch:
> 
> Warning (files): Missing ‘lexical-binding’ cookie in "/tmp/emacs-int-comp-subr--trampoline-72756e2d686f6f6b73_run_hooks_0-ZQkOM2.el".
> You can add one with ‘M-x elisp-enable-lexical-binding RET’.
> See ‘(elisp)Selecting Lisp Dialect’ and ‘(elisp)Converting to Lexical Binding’
> for more information.
> Compiling $HOME/.config/emacs/eln-cache/31.0.50-45ab2aa9/subr--trampoline-72756e2d686f6f6b73_run_hooks_0.eln...

Please show a recipe to reproduce this problem starting from "emacs -Q".
Or at least figure out and tell here compilation of what ELisp file
triggered this message (it sounds like it's part of your init
configuration?).  I started "emacs -Q", but didn't see any such
messages that I could use as a starting point for investigation.

Or, if I'm missing something, could you suggest how to investigate
this given the information you provided above?

Thanks.

Message #11 received at 78818 <at> debbugs.gnu.org (full text, mbox):

From: Daniel Mendler <mail <at> daniel-mendler.de>
To: Eli Zaretskii <eliz <at> gnu.org>
Cc: Andrea Corallo <acorallo <at> gnu.org>, 78818 <at> debbugs.gnu.org
Subject: Re: bug#78818: 31.0.50; Missing lexical-binding cookies when
 compiling trampolines
Date: Wed, 18 Jun 2025 13:52:42 +0200

Eli Zaretskii <eliz <at> gnu.org> writes:

>> Date: Tue, 17 Jun 2025 20:38:20 +0200
>> From:  Daniel Mendler via "Bug reports for GNU Emacs,
>>  the Swiss army knife of text editors" <bug-gnu-emacs <at> gnu.org>
>> 
>> In the *Native-compile-Log* I see the following messages on a newly
>> compiled Emacs 31 from the current Emacs master branch:
>> 
>> Warning (files): Missing ‘lexical-binding’ cookie in "/tmp/emacs-int-comp-subr--trampoline-72756e2d686f6f6b73_run_hooks_0-ZQkOM2.el".
>> You can add one with ‘M-x elisp-enable-lexical-binding RET’.
>> See ‘(elisp)Selecting Lisp Dialect’ and ‘(elisp)Converting to Lexical Binding’
>> for more information.
>> Compiling $HOME/.config/emacs/eln-cache/31.0.50-45ab2aa9/subr--trampoline-72756e2d686f6f6b73_run_hooks_0.eln...
>
> Please show a recipe to reproduce this problem starting from "emacs -Q".
> Or at least figure out and tell here compilation of what ELisp file
> triggered this message (it sounds like it's part of your init
> configuration?).  I started "emacs -Q", but didn't see any such
> messages that I could use as a starting point for investigation.
>
> Or, if I'm missing something, could you suggest how to investigate
> this given the information you provided above?

The trampoline .el file is generated by `comp--final' in comp.el. I
found this by grepping for `emacs-int-comp'. The generated Elisp file
doesn't include a `lexical-binding' cookie, which seems to trigger the
warning. As far as I understand the trampolines are generated if native
subrs are advised in the configuration.

Daniel

Message #14 received at 78818 <at> debbugs.gnu.org (full text, mbox):

From: Eli Zaretskii <eliz <at> gnu.org>
To: Daniel Mendler <mail <at> daniel-mendler.de>
Cc: acorallo <at> gnu.org, 78818 <at> debbugs.gnu.org
Subject: Re: bug#78818: 31.0.50; Missing lexical-binding cookies when
 compiling trampolines
Date: Wed, 18 Jun 2025 15:14:51 +0300

> From: Daniel Mendler <mail <at> daniel-mendler.de>
> Cc: 78818 <at> debbugs.gnu.org, Andrea Corallo <acorallo <at> gnu.org>
> Date: Wed, 18 Jun 2025 13:52:42 +0200
> 
> Eli Zaretskii <eliz <at> gnu.org> writes:
> 
> >> Date: Tue, 17 Jun 2025 20:38:20 +0200
> >> From:  Daniel Mendler via "Bug reports for GNU Emacs,
> >>  the Swiss army knife of text editors" <bug-gnu-emacs <at> gnu.org>
> >> 
> >> In the *Native-compile-Log* I see the following messages on a newly
> >> compiled Emacs 31 from the current Emacs master branch:
> >> 
> >> Warning (files): Missing ‘lexical-binding’ cookie in "/tmp/emacs-int-comp-subr--trampoline-72756e2d686f6f6b73_run_hooks_0-ZQkOM2.el".
> >> You can add one with ‘M-x elisp-enable-lexical-binding RET’.
> >> See ‘(elisp)Selecting Lisp Dialect’ and ‘(elisp)Converting to Lexical Binding’
> >> for more information.
> >> Compiling $HOME/.config/emacs/eln-cache/31.0.50-45ab2aa9/subr--trampoline-72756e2d686f6f6b73_run_hooks_0.eln...
> >
> > Please show a recipe to reproduce this problem starting from "emacs -Q".
> > Or at least figure out and tell here compilation of what ELisp file
> > triggered this message (it sounds like it's part of your init
> > configuration?).  I started "emacs -Q", but didn't see any such
> > messages that I could use as a starting point for investigation.
> >
> > Or, if I'm missing something, could you suggest how to investigate
> > this given the information you provided above?
> 
> The trampoline .el file is generated by `comp--final' in comp.el. I
> found this by grepping for `emacs-int-comp'. The generated Elisp file
> doesn't include a `lexical-binding' cookie, which seems to trigger the
> warning. As far as I understand the trampolines are generated if native
> subrs are advised in the configuration.

Thanks.  We insert the lexical-binding cookie in
comp--run-async-workers, but maybe trampoline compilation doesn't use
that?

Andrea, any suggestions?

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