bug#46508: 27.1; Emacs doesn't like ⿰

bug#46508: 27.1; Emacs doesn't like ⿰

[Ben Bullock]

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To reproduce this bug,

cat ⿰ > file
emacs -Q file

In XWindows, Emacs seems to hang up when opening a file with this
character in it. However, it is working inside the gnome-terminal (I am
using emacs -nw to write this).

In GNU Emacs 27.1 (build 1, i386-portbld-freebsd12.1, GTK+ Version 3.24.24,
cairo version 1.16.0)
System Description: 12.2-RELEASE-p3

Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.
Mark set
Making completion list... [2 times]
scroll-up-command: End of buffer

Configured using:
 'configure --disable-build-details --localstatedir=/var --with-x
 --enable-acl --with-cairo --with-dbus --without-gconf --with-gif
 --with-gnutls --with-gsettings --with-x-toolkit=gtk3 --with-harfbuzz
 --with-jpeg --with-json --with-file-notification=kqueue --with-lcms2
 --with-m17n-flt --without-imagemagick --with-mailutils --with-modules
 --with-sound=oss --with-libotf --with-png --with-toolkit-scroll-bars
 --with-rsvg --with-threads --with-tiff --with-xft --with-xim
 --with-xml2 --with-xpm --without-xwidgets --x-libraries=/usr/local/lib
 --x-includes=/usr/local/include --prefix=/usr/local
 --mandir=/usr/local/man --disable-silent-rules
 --infodir=/usr/local/share/emacs/info/ --build=i386-portbld-freebsd12.1
 'CFLAGS=-O2 -pipe -fstack-protector-strong -isystem /usr/local/include
 -fno-strict-aliasing ' 'CPPFLAGS=-isystem /usr/local/include' 'LDFLAGS=
 -fstack-protector-strong -L/usr/local/lib ''

Configured features:
XPM JPEG TIFF GIF PNG RSVG CAIRO SOUND DBUS GSETTINGS GLIB NOTIFY KQUEUE
ACL GNUTLS LIBXML2 FREETYPE HARFBUZZ M17N_FLT LIBOTF ZLIB
TOOLKIT_SCROLL_BARS GTK3 X11 XDBE XIM MODULES THREADS JSON PDUMPER LCMS2
GMP

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

Major mode: Fundamental

Minor modes in effect:
  savehist-mode: t
  show-paren-mode: t
  tooltip-mode: t
  global-eldoc-mode: t
  mouse-wheel-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  column-number-mode: t
  line-number-mode: t
  transient-mark-mode: t

Load-path shadows:
/usr/home/ben/config/emacs/ruby-mode hides
/usr/local/share/emacs/27.1/lisp/progmodes/ruby-mode
/usr/home/ben/config/emacs/cperl-mode hides
/usr/local/share/emacs/27.1/lisp/progmodes/cperl-mode

Features:
(shadow sort mail-extr emacsbug message rmc puny dired dired-loaddefs
format-spec rfc822 mml mml-sec epa epg epg-config gnus-util rmail
rmail-loaddefs text-property-search time-date mm-decode mm-bodies
mm-encode mail-parse rfc2231 mailabbrev gmm-utils mailheader sendmail
rfc2047 rfc2045 ietf-drums mm-util mail-prsvr mail-utils term/xterm
xterm savehist japan-util ff-mode table-readable-mode derived advice
edmacro kmacro paren server finder-inf package easymenu browse-url
url-handlers url-parse auth-source cl-seq eieio eieio-core cl-macs
eieio-loaddefs password-cache json subr-x map url-vars seq byte-opt gv
bytecomp byte-compile cconv cl-loaddefs cl-lib tooltip eldoc electric
uniquify ediff-hook vc-hooks lisp-float-type 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 elisp-mode lisp-mode
prog-mode register page tab-bar menu-bar rfn-eshadow isearch timer
select scroll-bar mouse jit-lock font-lock syntax facemenu 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 loaddefs
button faces cus-face macroexp files text-properties overlay sha1 md5
base64 format env code-pages mule custom widget hashtable-print-readable
backquote threads dbusbind kqueue lcms2 dynamic-setting
system-font-setting font-render-setting cairo move-toolbar gtk x-toolkit
x multi-tty make-network-process emacs)

Memory information:
((conses 8 75173 5699)
 (symbols 24 8518 1)
 (strings 16 23859 3294)
 (string-bytes 1 747583)
 (vectors 8 12429)
 (vector-slots 4 207547 5958)
 (floats 8 29 19)
 (intervals 28 272 1)
 (buffers 568 13))



-- 
 <ben@mikan>

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bug#46508: 27.1; Emacs doesn't like ⿰

[Andreas Schwab]

On Feb 14 2021, Ben Bullock wrote:

> To reproduce this bug,
>
> cat ⿰ > file
> emacs -Q file
>
> In XWindows, Emacs seems to hang up when opening a file with this
> character in it.

Does it really hang forever, or just take a lot of time trying to look
up a font for the character?

Andreas.

-- 
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510  2552 DF73 E780 A9DA AEC1
"And now for something completely different."

bug#46508: 27.1; Emacs doesn't like ⿰

[Ben Bullock]

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On Sun, 14 Feb 2021 at 20:56, Andreas Schwab <schwab@linux-m68k.org> wrote:

> On Feb 14 2021, Ben Bullock wrote:
>
> > To reproduce this bug,
> >
> > cat ⿰ > file
> > emacs -Q file
> >
> > In XWindows, Emacs seems to hang up when opening a file with this
> > character in it.
>
> Does it really hang forever, or just take a lot of time trying to look
> up a font for the character?
>

It just takes a lot of time, several minutes.

Further information about this:

I installed Google Fonts and Noto using

pkg install google-fonts
pkg install noto

(freebsd)

The problem happened after that. gnome-terminal continued to operate.

I found that if I waited several minutes, something would appear.

After uninstalling google-fonts and noto again, Emacs was behaving normally.

Thank you.


> Andreas.
>
> --
> Andreas Schwab, schwab@linux-m68k.org
> GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510  2552 DF73 E780 A9DA AEC1
> "And now for something completely different."
>

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bug#46508: 27.1; Emacs doesn't like ⿰

[Andreas Schwab]

What is the value of (frame-parameter nil 'font-backend)?
Does it help to run (set-frame-parameter nil 'font-backend (remove 'x
(frame-parameter nil 'font-backend)))?

Andreas.

-- 
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510  2552 DF73 E780 A9DA AEC1
"And now for something completely different."

bug#46508: 27.1; Emacs doesn't like ⿰

[Ben Bullock]

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On Mon, 15 Feb 2021 at 17:23, Andreas Schwab <schwab@linux-m68k.org> wrote:

> What is the value of (frame-parameter nil 'font-backend)?
>

I ran this in *scratch*:

(message "%s" (frame-parameter nil 'font-backend))

and it says

(ftcrhb x)


> Does it help to run (set-frame-parameter nil 'font-backend (remove 'x
> (frame-parameter nil 'font-backend)))?
>

I reinstalled google-fonts using

pkg install google-fonts

as su (root) followed by

xset fp rehash

This caused the problem to occur again and emacs -Q stalled completely. I
then restarted emacs with emacs -Q without opening the problem file (which
contains a single ⿰). In the new Emacs window I copy-pasted the above code
and ran 'eval-buffer' then I used C-x C-f to load the file containing the ⿰
single character. I then started typing this email, and it is still unable
to load the file containing the ⿰ even as I am typing now. It finally
loaded after several minutes, but the ⿰ character is not displayed, instead
there is a box with 2FF0 in it.

Here is a screenshot if it helps:

https://imgur.com/a/Cz99NnQ

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bug#46508: 27.1; Emacs doesn't like ⿰

[Robert Pluim]

>>>>> On Tue, 16 Feb 2021 16:14:00 +0900, Ben Bullock <benkasminbullock@gmail.com> said:

    Ben> This caused the problem to occur again and emacs -Q stalled completely. I
    Ben> then restarted emacs with emacs -Q without opening the problem file (which
    Ben> contains a single ⿰). In the new Emacs window I copy-pasted the above code
    Ben> and ran 'eval-buffer' then I used C-x C-f to load the file containing the ⿰
    Ben> single character. I then started typing this email, and it is still unable
    Ben> to load the file containing the ⿰ even as I am typing now. It finally
    Ben> loaded after several minutes, but the ⿰ character is not displayed, instead
    Ben> there is a box with 2FF0 in it.

I have no problems displaying that codepoint, because I have a
scalable font installed that can display the character, whereas you
only have a bitmap font. 'C-u C-x =' on the problematic character
shows:

    ftcrhb:-GOOG-Noto Serif CJK TC-normal-normal-normal-*-27-*-*-*-*-0-iso10646-1 (#x568)

so perhaps thereʼs a google-noto package you can install.

Robert

bug#46508: 27.1; Emacs doesn't like ⿰

[Werner LEMBERG]

> Ben> This caused the problem to occur again and emacs -Q stalled
> Ben> completely. I then restarted emacs with emacs -Q without
> Ben> opening the problem file (which contains a single ⿰). In the
> Ben> new Emacs window I copy-pasted the above code and ran
> Ben> 'eval-buffer' then I used C-x C-f to load the file containing
> Ben> the ⿰ single character. I then started typing this email, and
> Ben> it is still unable to load the file containing the ⿰ even as I
> Ben> am typing now. It finally loaded after several minutes, but the
> Ben> ⿰ character is not displayed, instead there is a box with 2FF0
> Ben> in it.
>
> I have no problems displaying that codepoint, because I have a
> scalable font installed that can display the character, [...]

Exactly.  However, this is not always the case, and the freeze of
Emacs is very, very annoying.  Other applications like my KDE terminal
is stalled only for approx. a second in similar situations.

Is there something that could be done on the Emacs side to improve its
behaviour?  For example, putting the font retrieving process into a
separate thread, providing a dummy glyph until the real one is
available?  Or maybe something else?  What does the terminal do to be
so much faster?


    Werner

bug#46508: 27.1; Emacs doesn't like ⿰

[Eli Zaretskii]

> Date: Tue, 16 Feb 2021 10:28:32 +0100 (CET)
> From: Werner LEMBERG <wl@gnu.org>
> Cc: schwab@linux-m68k.org, benkasminbullock@gmail.com, 46508@debbugs.gnu.org
> 
> Exactly.  However, this is not always the case, and the freeze of
> Emacs is very, very annoying.  Other applications like my KDE terminal
> is stalled only for approx. a second in similar situations.

Terminal emulators typically try a much smaller set of fonts than
Emacs does, because they generally use only fixed-pitch fonts, AFAIK.

> Is there something that could be done on the Emacs side to improve its
> behaviour?

Customizing your fontset would be one way.

> For example, putting the font retrieving process into a separate
> thread, providing a dummy glyph until the real one is available?

That's quite a project: the font search code accesses Lisp data
structures, so running that asynchronously would need some kind of
locking or working on copies of those Lisp data structures or
somesuch.  And then we'd need some mechanism to trigger redisplay once
the search is over.

> What does the terminal do to be so much faster?

That's an excellent question, to which I'd love to know the answer.