bug#47162: Mouse Wheel Won't Work When Emacs Built without Any Window System

["Basil L. Contovounesios" via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

[-- Attachment #1: Type: text/plain, Size: 1326 bytes --]

Eli Zaretskii <eliz@gnu.org> writes:

>> Cc: 张强 <johnson9009@163.com>, 47162@debbugs.gnu.org
>> Date: Fri, 30 Jul 2021 09:32:22 +0100
>> From:  "Basil L. Contovounesios" via "Bug reports for GNU Emacs,
>>  the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
>> 
>> > I've now made this change in Emacs 28.
>> 
>> FYI, as a result of this change mwheel is now effectively preloaded even
>> --without-x, in the sense that (featurep 'mwheel) returns non-nil even
>> when starting nox builds with -Q (see my signature for details).
>> 
>> Bother or feature?
>
> It's probably a bother, but could you please show the details, like
> what causes mwheel to be loaded at startup or at loadup time in the
> "--without-x" builds?

I built Emacs before and after commit 0aad4d134f, and attach the
resulting configurations as well as their diff.  Note that some other
libraries such as pp are also being loaded in the latter configuration.

After the autoload, I get the attached GDB backtrace with the following:

0. gdb ./emacs
1. set logging file gdb-after.txt
2. set logging on
3. b lread.c:1215 if !strncmp (SDATA (file), "mwheel", 6)
4. r -Q
5. bt

So it seems to be the reevaluation of custom-delayed-init-variables in
command-line that is loading mwheel at startup.

-- 
Basil


[-- Attachment #2: Emacs configuration before autoload --]
[-- Type: text/plain, Size: 2456 bytes --]

In GNU Emacs 28.0.50 (build 3, x86_64-pc-linux-gnu)
 of 2021-07-30 built on tia
Repository revision: 1219207a82740fc6ac21f178cacbe30e6aff9e7b
Repository branch: HEAD
System Description: Debian GNU/Linux 11 (bullseye)

Configured using:
 'configure 'CC=ccache gcc' 'CFLAGS=-O0 -g3 -ggdb'
 --prefix=/home/blc/.local --program-suffix=-nox-mwheel-before
 --with-file-notification=yes --with-x-toolkit=no --without-x'

Configured features:
ACL DBUS GMP GNUTLS GPM JSON LCMS2 LIBSELINUX LIBSYSTEMD LIBXML2 MODULES
NOTIFY INOTIFY PDUMPER SOUND THREADS XIM ZLIB

Important settings:
  value of $LANG: en_IE.UTF-8
  value of $XMODIFIERS: @im=ibus
  locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-mode: t
  global-eldoc-mode: t
  eldoc-mode: t
  electric-indent-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message rmc puny dired dired-loaddefs
rfc822 mml mml-sec epa derived epg epg-config gnus-util rmail tool-bar
rmail-loaddefs auth-source cl-seq eieio eieio-core cl-macs
eieio-loaddefs password-cache json map text-property-search time-date
subr-x seq mm-decode mm-bodies mm-encode mail-parse rfc2231 mailabbrev
gmm-utils mailheader cl-loaddefs cl-lib sendmail rfc2047 rfc2045
ietf-drums mm-util mail-prsvr mail-utils term/xterm xterm byte-opt gv
bytecomp byte-compile cconv regexp-opt iso-transl tooltip eldoc electric
uniquify ediff-hook vc-hooks lisp-float-type tabulated-list replace
newcomment text-mode elisp-mode lisp-mode prog-mode register page
tab-bar menu-bar rfn-eshadow isearch easymenu timer select mouse
jit-lock font-lock syntax font-core term/tty-colors frame minibuffer
cl-generic cham georgian utf-8-lang misc-lang vietnamese tibetan thai
tai-viet lao korean japanese eucjp-ms cp51932 hebrew greek romanian
slovak czech european ethiopic indian cyrillic chinese composite
charscript charprop case-table epa-hook jka-cmpr-hook help simple abbrev
obarray cl-preloaded nadvice button loaddefs faces cus-face macroexp
files window text-properties overlay sha1 md5 base64 format env
code-pages mule custom widget hashtable-print-readable backquote threads
dbusbind inotify lcms2 multi-tty make-network-process emacs)

[-- Attachment #3: Emacs configuration after autoload --]
[-- Type: text/plain, Size: 2536 bytes --]

In GNU Emacs 28.0.50 (build 2, x86_64-pc-linux-gnu)
 of 2021-07-30 built on tia
Repository revision: 0aad4d134f481662e621aea62c6633678a1387e1
Repository branch: HEAD
System Description: Debian GNU/Linux 11 (bullseye)

Configured using:
 'configure 'CC=ccache gcc' 'CFLAGS=-O0 -g3 -ggdb'
 --prefix=/home/blc/.local --program-suffix=-nox-mwheel-after
 --with-file-notification=yes --with-x-toolkit=no --without-x'

Configured features:
ACL DBUS GMP GNUTLS GPM JSON LCMS2 LIBSELINUX LIBSYSTEMD LIBXML2 MODULES
NOTIFY INOTIFY PDUMPER SOUND THREADS XIM ZLIB

Important settings:
  value of $LANG: en_IE.UTF-8
  value of $XMODIFIERS: @im=ibus
  locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

Minor modes in effect:
  mouse-wheel-mode: t
  tooltip-mode: t
  global-eldoc-mode: t
  eldoc-mode: t
  electric-indent-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message rmc puny dired dired-loaddefs
rfc822 mml mml-sec epa derived epg epg-config gnus-util rmail
rmail-loaddefs auth-source cl-seq eieio eieio-core cl-macs
eieio-loaddefs password-cache json map text-property-search time-date
subr-x seq mm-decode mm-bodies mm-encode mail-parse rfc2231 mailabbrev
gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums mm-util
mail-prsvr mail-utils pp cl-print thingatpt help-fns radix-tree
help-mode tool-bar cl-loaddefs cl-lib term/xterm xterm byte-opt gv
bytecomp byte-compile cconv regexp-opt mwheel iso-transl tooltip eldoc
electric uniquify ediff-hook vc-hooks lisp-float-type tabulated-list
replace newcomment text-mode elisp-mode lisp-mode prog-mode register
page tab-bar menu-bar rfn-eshadow isearch easymenu timer select mouse
jit-lock font-lock syntax font-core term/tty-colors frame minibuffer
cl-generic cham georgian utf-8-lang misc-lang vietnamese tibetan thai
tai-viet lao korean japanese eucjp-ms cp51932 hebrew greek romanian
slovak czech european ethiopic indian cyrillic chinese composite
charscript charprop case-table epa-hook jka-cmpr-hook help simple abbrev
obarray cl-preloaded nadvice button loaddefs faces cus-face macroexp
files window text-properties overlay sha1 md5 base64 format env
code-pages mule custom widget hashtable-print-readable backquote threads
dbusbind inotify lcms2 multi-tty make-network-process emacs)

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #4: Diff of Emacs configurations before and after autoload --]
[-- Type: text/x-diff, Size: 2509 bytes --]

--- configuration-before.txt	2021-07-30 16:41:18.468692030 +0100
+++ configuration-after.txt	2021-07-30 16:06:32.624236581 +0100
@@ -1,12 +1,12 @@
-In GNU Emacs 28.0.50 (build 3, x86_64-pc-linux-gnu)
+In GNU Emacs 28.0.50 (build 2, x86_64-pc-linux-gnu)
  of 2021-07-30 built on tia
-Repository revision: 1219207a82740fc6ac21f178cacbe30e6aff9e7b
+Repository revision: 0aad4d134f481662e621aea62c6633678a1387e1
 Repository branch: HEAD
 System Description: Debian GNU/Linux 11 (bullseye)
 
 Configured using:
  'configure 'CC=ccache gcc' 'CFLAGS=-O0 -g3 -ggdb'
- --prefix=/home/blc/.local --program-suffix=-nox-mwheel-before
+ --prefix=/home/blc/.local --program-suffix=-nox-mwheel-after
  --with-file-notification=yes --with-x-toolkit=no --without-x'
 
 Configured features:
@@ -21,6 +21,7 @@ Important settings:
 Major mode: Lisp Interaction
 
 Minor modes in effect:
+  mouse-wheel-mode: t
   tooltip-mode: t
   global-eldoc-mode: t
   eldoc-mode: t
@@ -41,16 +42,17 @@ None found.
 
 Features:
 (shadow sort mail-extr emacsbug message rmc puny dired dired-loaddefs
-rfc822 mml mml-sec epa derived epg epg-config gnus-util rmail tool-bar
+rfc822 mml mml-sec epa derived epg epg-config gnus-util rmail
 rmail-loaddefs auth-source cl-seq eieio eieio-core cl-macs
 eieio-loaddefs password-cache json map text-property-search time-date
 subr-x seq mm-decode mm-bodies mm-encode mail-parse rfc2231 mailabbrev
-gmm-utils mailheader cl-loaddefs cl-lib sendmail rfc2047 rfc2045
-ietf-drums mm-util mail-prsvr mail-utils term/xterm xterm byte-opt gv
-bytecomp byte-compile cconv regexp-opt iso-transl tooltip eldoc electric
-uniquify ediff-hook vc-hooks lisp-float-type tabulated-list replace
-newcomment text-mode elisp-mode lisp-mode prog-mode register page
-tab-bar menu-bar rfn-eshadow isearch easymenu timer select mouse
+gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums mm-util
+mail-prsvr mail-utils pp cl-print thingatpt help-fns radix-tree
+help-mode tool-bar cl-loaddefs cl-lib term/xterm xterm byte-opt gv
+bytecomp byte-compile cconv regexp-opt mwheel iso-transl tooltip eldoc
+electric uniquify ediff-hook vc-hooks lisp-float-type tabulated-list
+replace newcomment text-mode elisp-mode lisp-mode prog-mode register
+page tab-bar menu-bar rfn-eshadow isearch easymenu timer select mouse
 jit-lock font-lock syntax font-core term/tty-colors frame minibuffer
 cl-generic cham georgian utf-8-lang misc-lang vietnamese tibetan thai
 tai-viet lao korean japanese eucjp-ms cp51932 hebrew greek romanian

[-- Attachment #5: GDB backtrace after autoload --]
[-- Type: text/plain, Size: 4792 bytes --]

Breakpoint 2 at 0x1fcacf: file lread.c, line 1215.
Starting program: /home/blc/.local/src/emacs-mwheel-after/src/emacs -Q
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".

Breakpoint 2, Fload (file=XIL(0x7ffff48db8ac), noerror=XIL(0), nomessage=XIL(0x30), nosuffix=XIL(0), 
    must_suffix=XIL(0x30)) at lread.c:1215
1215	  if (! NILP (noerror))
#0  Fload (file=XIL(0x7ffff48db8ac), noerror=XIL(0), nomessage=XIL(0x30), nosuffix=XIL(0), must_suffix=XIL(0x30))
    at lread.c:1215
#1  0x00005555557519d0 in save_match_data_load (file=XIL(0x7ffff48db8ac), noerror=XIL(0), nomessage=XIL(0x30), 
    nosuffix=XIL(0), must_suffix=XIL(0x30)) at lread.c:1569
#2  0x000055555571e44d in Fautoload_do_load (fundef=XIL(0x7ffff4936bb3), funname=XIL(0x2aaa9ed4a090), 
    macro_only=XIL(0)) at eval.c:2188
#3  0x00005555557205c1 in Ffuncall (nargs=2, args=0x7fffffffbab8) at eval.c:2931
#4  0x000055555576a076 in exec_byte_code (bytestr=XIL(0x7ffff49a0a0c), vector=XIL(0x7ffff472590d), 
    maxdepth=make_fixnum(4), args_template=make_fixnum(514), nargs=2, args=0x7fffffffbfa8) at bytecode.c:632
#5  0x0000555555720afe in fetch_and_exec_byte_code (fun=XIL(0x7ffff47258dd), syms_left=make_fixnum(514), nargs=2, 
    args=0x7fffffffbf98) at eval.c:3036
#6  0x0000555555720e8b in funcall_lambda (fun=XIL(0x7ffff47258dd), nargs=2, arg_vector=0x7fffffffbf98) at eval.c:3117
#7  0x00005555557204a3 in Ffuncall (nargs=3, args=0x7fffffffbf90) at eval.c:2916
#8  0x000055555576a076 in exec_byte_code (bytestr=XIL(0x7ffff48b9ca4), vector=XIL(0x7ffff48b9c75), 
    maxdepth=make_fixnum(6), args_template=make_fixnum(257), nargs=1, args=0x7fffffffc480) at bytecode.c:632
#9  0x0000555555720afe in fetch_and_exec_byte_code (fun=XIL(0x7ffff48b9c45), syms_left=make_fixnum(257), nargs=1, 
    args=0x7fffffffc478) at eval.c:3036
#10 0x0000555555720e8b in funcall_lambda (fun=XIL(0x7ffff48b9c45), nargs=1, arg_vector=0x7fffffffc478) at eval.c:3117
#11 0x00005555557204a3 in Ffuncall (nargs=2, args=0x7fffffffc470) at eval.c:2916
#12 0x000055555571fd38 in call1 (fn=XIL(0x2aaa9eccd210), arg1=XIL(0x2aaa9ed4a090)) at eval.c:2774
#13 0x000055555572e466 in mapcar1 (leni=24, vals=0x0, fn=XIL(0x2aaa9eccd210), seq=XIL(0x7ffff474e463)) at fns.c:2794
#14 0x000055555572e88e in Fmapc (function=XIL(0x2aaa9eccd210), sequence=XIL(0x7ffff474e463)) at fns.c:2867
#15 0x0000555555720872 in funcall_subr (subr=0x555555b7c6a0 <Smapc>, numargs=2, args=0x7fffffffc690) at eval.c:2989
#16 0x000055555572045f in Ffuncall (nargs=3, args=0x7fffffffc688) at eval.c:2914
#17 0x000055555576a076 in exec_byte_code (bytestr=XIL(0x7ffff48ba6bc), vector=XIL(0x7ffff48a7c8d), 
    maxdepth=make_fixnum(14), args_template=make_fixnum(0), nargs=0, args=0x7fffffffd148) at bytecode.c:632
#18 0x0000555555720afe in fetch_and_exec_byte_code (fun=XIL(0x7ffff48a7c5d), syms_left=make_fixnum(0), nargs=0, 
    args=0x7fffffffd148) at eval.c:3036
#19 0x0000555555720e8b in funcall_lambda (fun=XIL(0x7ffff48a7c5d), nargs=0, arg_vector=0x7fffffffd148) at eval.c:3117
#20 0x00005555557204a3 in Ffuncall (nargs=1, args=0x7fffffffd140) at eval.c:2916
#21 0x000055555576a076 in exec_byte_code (bytestr=XIL(0x7ffff48bc624), vector=XIL(0x7ffff48a7245), 
    maxdepth=make_fixnum(9), args_template=make_fixnum(0), nargs=0, args=0x7fffffffd780) at bytecode.c:632
#22 0x0000555555720afe in fetch_and_exec_byte_code (fun=XIL(0x7ffff48a7215), syms_left=make_fixnum(0), nargs=0, 
    args=0x7fffffffd780) at eval.c:3036
#23 0x0000555555720e8b in funcall_lambda (fun=XIL(0x7ffff48a7215), nargs=0, arg_vector=0x7fffffffd780) at eval.c:3117
#24 0x0000555555720ca8 in apply_lambda (fun=XIL(0x7ffff48a7215), args=XIL(0), count=4) at eval.c:3061
#25 0x000055555571f0d3 in eval_sub (form=XIL(0x7ffff4c66f73)) at eval.c:2436
#26 0x000055555571e5d0 in Feval (form=XIL(0x7ffff4c66f73), lexical=XIL(0)) at eval.c:2220
#27 0x000055555566915e in top_level_2 () at keyboard.c:1103
#28 0x000055555571cba6 in internal_condition_case (bfun=0x55555566913b <top_level_2>, handlers=XIL(0x90), 
    hfun=0x555555668bf5 <cmd_error>) at eval.c:1439
#29 0x00005555556691a6 in top_level_1 (ignore=XIL(0)) at keyboard.c:1111
#30 0x000055555571c3b4 in internal_catch (tag=XIL(0xc3c0), func=0x555555669160 <top_level_1>, arg=XIL(0))
    at eval.c:1189
#31 0x0000555555669089 in command_loop () at keyboard.c:1072
#32 0x00005555556687c6 in recursive_edit_1 () at keyboard.c:720
#33 0x0000555555668949 in Frecursive_edit () at keyboard.c:789
#34 0x0000555555665473 in main (argc=2, argv=0x7fffffffdd08) at emacs.c:2050

Lisp Backtrace:
"mouse-wheel-mode" (0xffffbac0)
"custom-set-minor-mode" (0xffffbf98)
"custom-reevaluate-setting" (0xffffc478)
"mapc" (0xffffc690)
"command-line" (0xffffd148)
"normal-top-level" (0xffffd780)
quit