bug#65919: 29.1; build without xinput does not get focused when hovering over window

bug#65919: 29.1; build without xinput does not get focused when hovering over window

[Ivan Popovych via Bug reports for GNU Emacs, the Swiss army knife of text editors]

Steps to reproduce:
 Build Emacs 29 with configure flags as below
 $ echo "exec emacs -Q" > ~/.xinitrc
 $ startx
 Cursor is hollow when starting Emacs and hovering over or clicking in window
 Clicking menu bar item fixes the cursor.
 Building with `--without-xinput` fixes the issue.

Originally reported as EXWM bug in
https://github.com/ch11ng/exwm/issues/924 but this can be reproduced
even without EXWM


In GNU Emacs 29.1 (build 1, x86_64-pc-linux-gnu, X toolkit, cairo
version 1.16.0, Xaw3d scroll bars)
Windowing system distributor 'The X.Org Foundation', version 11.0.12101008
System Description: NixOS 23.11 (Tapir)

Configured using:
 'configure
 --prefix=/nix/store/81g0rphgaisjz1kf6mfdlqv9m69kjfkf-emacs-29.1
 --disable-build-details --with-modules --with-x-toolkit=lucid
 --with-xft --with-cairo --with-native-compilation --with-tree-sitter
 --with-xinput2'

Configured features:
CAIRO DBUS FREETYPE GIF GLIB GMP GNUTLS GPM GSETTINGS HARFBUZZ JPEG JSON
LIBOTF LIBSELINUX LIBSYSTEMD LIBXML2 M17N_FLT MODULES NATIVE_COMP NOTIFY
INOTIFY PDUMPER PNG RSVG SECCOMP SOUND SQLITE3 THREADS TIFF
TOOLKIT_SCROLL_BARS TREE_SITTER WEBP X11 XAW3D XDBE XIM XINPUT2 XPM
LUCID ZLIB

Important settings:
  value of $EMACSLOADPATH: /nix/store/f6rpc2qbrsn02vzyybqrhybl4n3zfdc0-emacs-packages-deps/share/emacs/site-lisp:
  value of $EMACSNATIVELOADPATH: /nix/store/f6rpc2qbrsn02vzyybqrhybl4n3zfdc0-emacs-packages-deps/share/emacs/native-lisp:
  value of $LANG: en_US.UTF-8
  locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

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

Load-path shadows:
/nix/store/f6rpc2qbrsn02vzyybqrhybl4n3zfdc0-emacs-packages-deps/share/emacs/site-lisp/elpa/let-alist-1.0.6/let-alist hides /nix/store/81g0rphgaisjz1kf6mfdlqv9m69kjfkf-emacs-29.1/share/emacs/29.1/lisp/emacs-lisp/let-alist

Features:
(shadow sort mail-extr emacsbug message mailcap yank-media puny dired
dired-loaddefs rfc822 mml mml-sec password-cache epa derived epg rfc6068
epg-config gnus-util text-property-search time-date mm-decode mm-bodies
mm-encode mail-parse rfc2231 mailabbrev gmm-utils mailheader cl-loaddefs
comp comp-cstr warnings icons subr-x rx cl-seq cl-macs gv cl-extra
help-mode bytecomp byte-compile cl-lib sendmail rfc2047 rfc2045
ietf-drums mm-util mail-prsvr mail-utils rmc iso-transl tooltip cconv
eldoc paren electric uniquify ediff-hook vc-hooks lisp-float-type
elisp-mode mwheel term/x-win x-win term/common-win x-dnd tool-bar dnd
fontset image regexp-opt fringe tabulated-list replace newcomment
text-mode lisp-mode prog-mode register page tab-bar menu-bar rfn-eshadow
isearch easymenu timer select scroll-bar mouse jit-lock font-lock syntax
font-core term/tty-colors frame minibuffer nadvice seq simple cl-generic
indonesian philippine 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 emoji-zwj charscript charprop case-table epa-hook
jka-cmpr-hook help abbrev obarray oclosure cl-preloaded button loaddefs
theme-loaddefs faces cus-face macroexp files window text-properties
overlay sha1 md5 base64 format env code-pages mule custom widget keymap
hashtable-print-readable backquote threads dbusbind inotify
dynamic-setting system-font-setting font-render-setting cairo x-toolkit
xinput2 x multi-tty make-network-process native-compile emacs)

Memory information:
((conses 16 78420 8285)
 (symbols 48 7140 0)
 (strings 32 20459 2047)
 (string-bytes 1 634737)
 (vectors 16 16614)
 (vector-slots 8 334479 10269)
 (floats 8 46 40)
 (intervals 56 255 0)
 (buffers 984 11))

bug#65919: 29.1; build without xinput does not get focused when hovering over window

[Po Lu via Bug reports for GNU Emacs, the Swiss army knife of text editors]

Ivan Popovych <ivan@ipvych.com> writes:

> Steps to reproduce:
>  Build Emacs 29 with configure flags as below
>  $ echo "exec emacs -Q" > ~/.xinitrc
>  $ startx
>  Cursor is hollow when starting Emacs and hovering over or clicking in window
>  Clicking menu bar item fixes the cursor.
>  Building with `--without-xinput` fixes the issue.
>
> Originally reported as EXWM bug in
> https://github.com/ch11ng/exwm/issues/924 but this can be reproduced
> even without EXWM

The subject and the body of your e-mail are contradictory.  Does the
build _with_ XInput2 fail to focus correctly, or does the build without?

bug#65919: 29.1; build without xinput does not get focused when hovering over window

[Ivan Popovych via Bug reports for GNU Emacs, the Swiss army knife of text editors]

Po Lu <luangruo@yahoo.com> writes:

> The subject and the body of your e-mail are contradictory.  Does the
> build _with_ XInput2 fail to focus correctly, or does the build without?

Sorry about that, subject is incorrect.  Build _with_ XInput2 fail to
focus correctly.

bug#65919: 29.1; build without xinput does not get focused when hovering over window

[Po Lu via Bug reports for GNU Emacs, the Swiss army knife of text editors]

Ivan Popovych <ivan@ipvych.com> writes:

> Po Lu <luangruo@yahoo.com> writes:
>
>> The subject and the body of your e-mail are contradictory.  Does the
>> build _with_ XInput2 fail to focus correctly, or does the build without?
>
> Sorry about that, subject is incorrect.  Build _with_ XInput2 fail to
> focus correctly.

OK.  Does the problem vanish if you switch to a no toolkit or GTK 3
build?

bug#65919: 29.1; build without xinput does not get focused when hovering over window

[Ivan Popovych via Bug reports for GNU Emacs, the Swiss army knife of text editors]

Po Lu <luangruo@yahoo.com> writes:

>
> OK.  Does the problem vanish if you switch to a no toolkit or GTK 3
> build?

Build with no toolkit has no issue

Configured using:
 'configure
 --prefix=/nix/store/zg0g00l2gyycf1xdl64j89sbnjrif62l-emacs-29.1
 --disable-build-details --with-modules --with-x-toolkit=no --with-xft
 --with-cairo --with-native-compilation --with-tree-sitter
 --with-xinput2'

Build with gtk3 has no issue

Configured using:
 'configure
 --prefix=/nix/store/y35rnh7np5m538gmw6qcsr6wcwrw9ls5-emacs-gtk3-29.1
 --disable-build-details --with-modules --with-x-toolkit=gtk3
 --with-xft --with-cairo --with-native-compilation --with-tree-sitter
 --with-xinput2 --with-xwidgets'

bug#65919: 29.1; build without xinput does not get focused when hovering over window

[Po Lu via Bug reports for GNU Emacs, the Swiss army knife of text editors]

Ivan Popovych <ivan@ipvych.com> writes:

> Po Lu <luangruo@yahoo.com> writes:
>
>>
>> OK.  Does the problem vanish if you switch to a no toolkit or GTK 3
>> build?
>
> Build with no toolkit has no issue
>
> Configured using:
>  'configure
>  --prefix=/nix/store/zg0g00l2gyycf1xdl64j89sbnjrif62l-emacs-29.1
>  --disable-build-details --with-modules --with-x-toolkit=no --with-xft
>  --with-cairo --with-native-compilation --with-tree-sitter
>  --with-xinput2'
>
> Build with gtk3 has no issue
>
> Configured using:
>  'configure
>  --prefix=/nix/store/y35rnh7np5m538gmw6qcsr6wcwrw9ls5-emacs-gtk3-29.1
>  --disable-build-details --with-modules --with-x-toolkit=gtk3
>  --with-xft --with-cairo --with-native-compilation --with-tree-sitter
>  --with-xinput2 --with-xwidgets'

Thanks.  I guess the problem arises from the core window focus code used
under X toolkit builds.

Would you please instrument x_focus_changed as follows:

diff --git a/src/xterm.c b/src/xterm.c
index 11ccd5ebdb3..cff9b2537d5 100644
--- a/src/xterm.c
+++ b/src/xterm.c
@@ -12005,6 +12005,8 @@ XTtoggle_invisible_pointer (struct frame *f, bool invisible)
 x_focus_changed (int type, int state, struct x_display_info *dpyinfo,
 		 struct frame *frame, struct input_event *bufp)
 {
+  fprintf (stderr, "x_focus_changed: %d %d %p\n",
+	   type, state, (void *) frame);
   if (type == FocusIn)
     {
       if (dpyinfo->x_focus_event_frame != frame)

and send us whatever is printed to standard output after moving the
pointer within the frame?

bug#65919: 29.1; build without xinput does not get focused when hovering over window

[Po Lu via Bug reports for GNU Emacs, the Swiss army knife of text editors]

This should be fixed on the master branch.  There is a minor issue,
however: the fix for this bug may negatively affect that of bug#57468.

Would either Lars or Robert confirm that the Lucid, Motif and GTK 2.x
builds still remain free of that bug?

TIA.

bug#65919: 29.1; build without xinput does not get focused when hovering over window

[Amin Bandali]

Hello,

Po Lu writes:

> This should be fixed on the master branch.  [...]

FYI your e1a730017d6 patch introduces the following compiler warning:

process.c: In function ‘child_signal_notify’:
process.c:7436:54: warning: suggest braces around empty body in an ‘if’ statement [-Wempty-body]
 7436 |     /* emacs_perror ("writing to child signal FD") */;
      |                                                      ^

bug#65919: 29.1; build without xinput does not get focused when hovering over window

[Po Lu via Bug reports for GNU Emacs, the Swiss army knife of text editors]

Amin Bandali <bandali@gnu.org> writes:

> Hello,
>
> Po Lu writes:
>
>> This should be fixed on the master branch.  [...]
>
> FYI your e1a730017d6 patch introduces the following compiler warning:
>
> process.c: In function ‘child_signal_notify’:
> process.c:7436:54: warning: suggest braces around empty body in an ‘if’ statement [-Wempty-body]
>  7436 |     /* emacs_perror ("writing to child signal FD") */;
>       |                                                      ^

Thanks.  Does this silence the warning?

diff --git a/configure.ac b/configure.ac
index 7ca75be996d..3b5f3c1c37a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1776,6 +1776,9 @@ AC_DEFUN
   # Emacs doesn't need this paranoia.
   nw="$nw -Wbidi-chars=any,ucn"
 
+  # Or this hysteria, which impedes commentary within if statements.
+  nw="$nw -Wempty-body"
+
   if test "$emacs_cv_clang" = yes; then
     nw="$nw -Wdouble-promotion"
     nm="$nm -Wunknown-pragmas"

bug#65919: 29.1; build without xinput does not get focused when hovering over window

[Amin Bandali]

Po Lu writes:

> Amin Bandali <bandali@gnu.org> writes:
>
>> Hello,
>>
>> Po Lu writes:
>>
>>> This should be fixed on the master branch.  [...]
>>
>> FYI your e1a730017d6 patch introduces the following compiler warning:
>>
>> process.c: In function ‘child_signal_notify’:
>> process.c:7436:54: warning: suggest braces around empty body in an ‘if’ statement [-Wempty-body]
>>  7436 |     /* emacs_perror ("writing to child signal FD") */;
>>       |                                                      ^
>
> Thanks.  Does this silence the warning?
>
> diff --git a/configure.ac b/configure.ac
> index 7ca75be996d..3b5f3c1c37a 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -1776,6 +1776,9 @@ AC_DEFUN
>    # Emacs doesn't need this paranoia.
>    nw="$nw -Wbidi-chars=any,ucn"
>  
> +  # Or this hysteria, which impedes commentary within if statements.
> +  nw="$nw -Wempty-body"
> +
>    if test "$emacs_cv_clang" = yes; then
>      nw="$nw -Wdouble-promotion"
>      nm="$nm -Wunknown-pragmas"
>

Thanks, but it doesn't seem to.  Also, IMHO this is a useful warning,
and the better fix would be to add the braces for that if statement.
That part of the code now looks quite fragile, and a problem waiting
to happen if that lone semicolon is accidentally mistakenly removed.

bug#65919: 29.1; build without xinput does not get focused when hovering over window

[Stefan Kangas]

Po Lu via "Bug reports for GNU Emacs, the Swiss army knife of text
editors" <bug-gnu-emacs@gnu.org> writes:

>> FYI your e1a730017d6 patch introduces the following compiler warning:
>>
>> process.c: In function ‘child_signal_notify’:
>> process.c:7436:54: warning: suggest braces around empty body in an ‘if’ statement [-Wempty-body]
>>  7436 |     /* emacs_perror ("writing to child signal FD") */;
>>       |                                                      ^
>
> Thanks.  Does this silence the warning?

AFAIU, the point here is to fix a warning in

    if (emacs_write (fd, &dummy, 1) != 1)
      /* emacs_perror ("writing to child signal FD") */;

for which the easiest solution should be

    emacs_write (fd, &dummy, 1);

This avoids having to disable -Wempty-body everywhere, which IMO doesn't
seems justified just to silence this one warning.

What am I missing?

bug#65919: 29.1; build without xinput does not get focused when hovering over window

[Bob Rogers]

   From: Po Lu <luangruo@yahoo.com>
   Date: Fri, 15 Sep 2023 10:38:18 +0800

   This should be fixed on the master branch.  There is a minor issue,
   however: the fix for this bug may negatively affect that of bug#57468.

   Would either Lars or Robert confirm that the Lucid, Motif and GTK 2.x
   builds still remain free of that bug?

   TIA.

I can confirm that there is no such bug in 1442f4043a7 with any of these
toolkits (nor with GTK3, which is what I normally use).

					-- Bob Rogers

bug#65919: 29.1; build without xinput does not get focused when hovering over window

[Po Lu via Bug reports for GNU Emacs, the Swiss army knife of text editors]

Stefan Kangas <stefankangas@gmail.com> writes:

> Po Lu via "Bug reports for GNU Emacs, the Swiss army knife of text
> editors" <bug-gnu-emacs@gnu.org> writes:
>
>>> FYI your e1a730017d6 patch introduces the following compiler warning:
>>>
>>> process.c: In function ‘child_signal_notify’:
>>> process.c:7436:54: warning: suggest braces around empty body in an ‘if’ statement [-Wempty-body]
>>>  7436 |     /* emacs_perror ("writing to child signal FD") */;
>>>       |                                                      ^
>>
>> Thanks.  Does this silence the warning?
>
> AFAIU, the point here is to fix a warning in
>
>     if (emacs_write (fd, &dummy, 1) != 1)
>       /* emacs_perror ("writing to child signal FD") */;
>
> for which the easiest solution should be
>
>     emacs_write (fd, &dummy, 1);
>
> This avoids having to disable -Wempty-body everywhere, which IMO doesn't
> seems justified just to silence this one warning.
>
> What am I missing?

It's not to fix a warning, but to communicate that we would like to call
`emacs_perror' there, yet cannot, given that it is not a reentrant
function.

bug#65919: 29.1; build without xinput does not get focused when hovering over window

[Po Lu via Bug reports for GNU Emacs, the Swiss army knife of text editors]

Bob Rogers <rogers@rgrjr.com> writes:

>    From: Po Lu <luangruo@yahoo.com>
>    Date: Fri, 15 Sep 2023 10:38:18 +0800
>
>    This should be fixed on the master branch.  There is a minor issue,
>    however: the fix for this bug may negatively affect that of bug#57468.
>
>    Would either Lars or Robert confirm that the Lucid, Motif and GTK 2.x
>    builds still remain free of that bug?
>
>    TIA.
>
> I can confirm that there is no such bug in 1442f4043a7 with any of these
> toolkits (nor with GTK3, which is what I normally use).
>
> 					-- Bob Rogers

OK, thanks for testing.

bug#65919: 29.1; build without xinput does not get focused when hovering over window

[Stefan Kangas]

Po Lu <luangruo@yahoo.com> writes:

> It's not to fix a warning, but to communicate that we would like to call
> `emacs_perror' there, yet cannot, given that it is not a reentrant
> function.

Right, but surely that can be done without disabling -Wempty-body.

bug#65919: 29.1; build without xinput does not get focused when hovering over window

[Eli Zaretskii]

> Cc: 65919@debbugs.gnu.org, Lars Ingebrigtsen <larsi@gnus.org>,
>  Ivan Popovych <ivan@ipvych.com>, Bob Rogers <rogers@rgrjr.com>
> From: Amin Bandali <bandali@gnu.org>
> Date: Thu, 14 Sep 2023 23:57:26 -0400
> 
> Hello,
> 
> Po Lu writes:
> 
> > This should be fixed on the master branch.  [...]
> 
> FYI your e1a730017d6 patch introduces the following compiler warning:
> 
> process.c: In function ‘child_signal_notify’:
> process.c:7436:54: warning: suggest braces around empty body in an ‘if’ statement [-Wempty-body]
>  7436 |     /* emacs_perror ("writing to child signal FD") */;
>       |                                                      ^

Thanks, should be fixed now.

bug#65919: 29.1; build without xinput does not get focused when hovering over window

[Ivan Popovych via Bug reports for GNU Emacs, the Swiss army knife of text editors]

Po Lu <luangruo@yahoo.com> writes:

> This should be fixed on the master branch.  There is a minor issue,
> however: the fix for this bug may negatively affect that of bug#57468.
>
> Would either Lars or Robert confirm that the Lucid, Motif and GTK 2.x
> builds still remain free of that bug?
>
> TIA.

Tested it as well, issue is gone, thank you.

bug#65919: 29.1; build without xinput does not get focused when hovering over window

[Po Lu via Bug reports for GNU Emacs, the Swiss army knife of text editors]

Ivan Popovych <ivan@ipvych.com> writes:

> Po Lu <luangruo@yahoo.com> writes:
>
>> This should be fixed on the master branch.  There is a minor issue,
>> however: the fix for this bug may negatively affect that of bug#57468.
>>
>> Would either Lars or Robert confirm that the Lucid, Motif and GTK 2.x
>> builds still remain free of that bug?
>>
>> TIA.
>
> Tested it as well, issue is gone, thank you.

Thanks, closing.