"Attempt to shape unibyte text" crash error

[mickeynp]

This issue only occurs on Emacs versions 27.1 and 27.2

Resolution

The quickest fix is to use the master branch of Emacs 27 and compile it yourself (something you are most likely doing anyway due to the slow adoption of new Emacs versions in most distros.)

If you haven't you should try out the native compilation branch also if you haven't.

Details

If you experience this issue on Emacsen newer than Emacs 27.2 when you generate ligatures, then please comment below but include the following:

• Your OS details;
• Build details of Emacs from M-x emacs-version;
• C-h v cairo-version-string;
• C-h v system-configuration-features;
• Your font, and the ligature configuration you are using;
• GUI or Terminal Emacs;
• Whether the issue happens in emacs -q or not.

It's likely a combination of harfbuzz; cairo (or lack thereof); your OS; your font; and the ligatures. Discovering common trends would be useful.

[benley]

• Your OS details;

NixOS 20.09.git.c59ea8b8a0e (Nightingale)

• Build details of Emacs from M-x emacs-version;

GNU Emacs 27.1 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.21, cairo version 1.16.0)

• C-h v cairo-version-string;

1.16.0

• C-h v system-configuration-features;

"XPM JPEG TIFF GIF PNG RSVG CAIRO SOUND DBUS GSETTINGS GLIB NOTIFY INOTIFY LIBSELINUX GNUTLS LIBXML2 FREETYPE HARFBUZZ M17N_FLT LIBOTF ZLIB TOOLKIT_SCROLL_BARS GTK3 X11 XDBE XIM MODULES THREADS LIBSYSTEMD JSON PDUMPER GMP"

• Your font, and the ligature configuration you are using;

PragmataPro Liga Regular, version 0.828

Ligature config:

(use-package ligature
  :config
  (ligature-set-ligatures t '("[ERROR]" "[DEBUG]" "[INFO]" "[WARN]" "[WARNING]"
                              "[ERR]" "[FATAL]" "[TRACE]" "[FIXME]" "[TODO]"
                              "[BUG]" "[NOTE]" "[HACK]" "[MARK]"
                              "# ERROR" "# DEBUG" "# INFO" "# WARN" "# WARNING"
                              "# ERR" "# FATAL" "# TRACE" "# FIXME" "# TODO"
                              "# BUG" "# NOTE" "# HACK" "# MARK"
                              "// ERROR" "// DEBUG" "// INFO" "// WARN" "// WARNING"
                              "// ERR" "// FATAL" "// TRACE" "// FIXME" "// TODO"
                              "// BUG" "// NOTE" "// HACK" "// MARK"
                              "!!" "!=" "!==" "!!!" "!≡" "!≡≡" "!>" "!=<" "#("
                              "#_" "#{" "#?" "#>" "##" "#_(" "%=" "%>" "%>%" "%<%"
                              "&%" "&&" "&*" "&+" "&-" "&/" "&=" "&&&" "&>" "$>"
                              "***" "*=" "*/" "*>" "++" "+++" "+=" "+>" "++=" "--"
                              "-<" "-<<" "-=" "->" "->>" "---" "-->" "-+-" "-\\/"
                              "-|>" "-<|" ".." "..." "..<" ".>" ".~" ".=" "/*" "//"
                              "/>" "/=" "/==" "///" "/**" ":::" "::" ":=" ":≡" ":>"
                              ":=>" ":(" ":-(" ":)" ":-)" ":/" ":\\" ":3" ":D" ":P"
                              ":>:" ":<:" "<$>" "<*" "<*>" "<+>" "<-" "<<" "<<<" "<<="
                              "<=" "<=>" "<>" "<|>" "<<-" "<|" "<=<" "<~" "<~~" "<<~"
                              "<$" "<+" "<!>" "<@>" "<#>" "<%>" "<^>" "<&>" "<?>" "<.>"
                              "</>" "<\\>" "<\">" "<:>" "<~>" "<**>" "<<^" "<!" "<@"
                              "<#" "<%" "<^" "<&" "<?" "<." "</" "<\\" "<\"" "<:" "<->"
                              "<!--" "<--" "<~<" "<==>" "<|-" "<<|" "<-<" "<-->" "<<=="
                              "<==" "=<<" "==" "===" "==>" "=>" "=~" "=>>" "=/=" "=~="
                              "==>>" "≡≡" "≡≡≡" "≡:≡" ">-" ">=" ">>" ">>-" ">>=" ">>>"
                              ">=>" ">>^" ">>|" ">!=" ">->" "??" "?~" "?=" "?>" "???"
                              "?." "^=" "^." "^?" "^.." "^<<" "^>>" "^>" "\\\\" "\\>"
                              "\\/-" "@>" "|=" "||" "|>" "|||" "|+|" "|->" "|-->" "|=>"
                              "|==>" "|>-" "|<<" "||>" "|>>" "|-" "||-" "~=" "~>" "~~>"
                              "~>>" "[[" "]]" "\">" "_|_"))
  (global-ligature-mode t))

Worth noting: If I remove :3 from the ligature list, the error doesn't seem to occur.

• GUI or Terminal Emacs;

GUI

• Whether the issue happens in emacs -q or not.

No, not unless I enable ligature.el features.

[vale981]

* Your OS details;

NixOS unstable

* Build details of Emacs from `M-x emacs-version`;

GNU Emacs 27.1 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.21, cairo version 1.16.0)

* `C-h v cairo-version-string`;

"1.16.0"

* `C-h v system-configuration-features`;

"XPM JPEG TIFF GIF PNG RSVG CAIRO SOUND DBUS GSETTINGS GLIB NOTIFY INOTIFY LIBSELINUX GNUTLS LIBXML2 FREETYPE HARFBUZZ M17N_FLT LIBOTF ZLIB TOOLKIT_SCROLL_BARS GTK3 X11 XDBE XIM MODULES THREADS LIBSYSTEMD JSON PDUMPER GMP"

* Your font, and the ligature configuration you are using;

The font is JetBrains Mono.

(use-package ligature
  :straight (:host github :repo "mickeynp/ligature.el")
  :config
  (ligature-set-ligatures 'prog-mode
                          '("-->" "//" "/**" "/*" "*/" "<!--" ":=" "->>" "<<-" "->" "<-"
                            "<=>" "==" "!=" "<=" ">=" "=:=" "!==" "&&" "||" "..." ".."
                            "|||" "///" "&&&" "===" "++" "--" "=>" "|>" "<|" "||>" "<||"
                            "|||>" "<|||" ">>" "<<" "::=" "|]" "[|" "{|" "|}"
                            "[<" ">]" ":?>" ":?" "/=" "[||]" "!!" "?:" "?." "::"
                            "+++" "??" "###" "##" ":::" "####" ".?" "?=" "=!=" "<|>"
                            "<:" ":<" ":>" ">:" "<>" "***" ";;" "/==" ".=" ".-" "__"
                            "=/=" "<-<" "<<<" ">>>" "<=<" "<<=" "<==" "<==>" "==>" "=>>"
                            ">=>" ">>=" ">>-" ">-" "<~>" "-<" "-<<" "=<<" "---" "<-|"
                            "<=|" "/\\" "\\/" "|=>" "|~>" "<~~" "<~" "~~" "~~>" "~>"
                            "<$>" "<$" "$>" "<+>" "<+" "+>" "<*>" "<*" "*>" "</>" "</" "/>"
                            "<->" "..<" "~=" "~-" "-~" "~@" "^=" "-|" "_|_" "|-" "||-"
                            "|=" "||=" "#{" "#[" "]#" "#(" "#?" "#_" "#_(" "#:" "#!" "#="
                            "&="))
  (global-ligature-mode t))

* GUI or Terminal Emacs;

GUI

* Whether the issue happens in `emacs -q` or not.

Does not unless ligature.el is loaded.
Among others // seems to cause problems.
It does not happen in pure prog-mode but in conjunction with python-mode, c++-mode...

[vale981]

Interesting: it also happens if the ligature list is completely empty :P
and it happens with cascadia code

Related http://emacs.1067599.n8.nabble.com/bug-42522-Emacs-27-100-CPU-when-setting-mode-name-with-ligatures-td515786.html#a517123
and https://www.reddit.com/r/emacs/comments/icem4s/emacs_271_freezes_when_using_font_ligatures/

This particular problem is fixed on emacs master, which will become emacs 28. Either use that, or try patching your emacs with commit fe903c5ab7354b97f80ecf1b01ca3ff1027be446

This commit seems to be related to the modeline.

[vale981]

I can confirm that the commit fixes the issue for me.
In nixos you can use:

let
  myEmacs = (pkgs.emacs.override {
    # Use gtk3 instead of the default gtk2
    withGTK3 = true;
    withGTK2 = false;
  }).overrideAttrs (old: {
     patches = (old.patches or []) ++ [
      (pkgs.fetchpatch {
        url = "https://github.com/emacs-mirror/emacs/commit/fe903c5ab7354b97f80ecf1b01ca3ff1027be446.patch";
        sha256 = "0srcgqdc9bhk992vr6yl4vq528fr5414wyz2wf0fxcpw3hz7mhq8";
      })
    ];
  });
in ...

[Alexander-Miller]

Here's something that can be reproduced from emacs -q:

(load "~/.emacs.d/straight/build/ligature/ligature.elc")
(require 'ligature)
(ligature-set-ligatures 't '("=>"))
(ligature-mode t)
(let ((ov (make-overlay 0 1)))
  (overlay-put ov 'after-string "=>"))

Creating the overlay doesn't crash Emacs. Instead it freezes while chugging 100% of a CPU core. kill -12 has no effect, so I can't provide a stack trace.

eros.el creates overlays starting with a =>, so that's where I first encountered this problem, otherwise all the ligatures seem to be fine.

Your OS details;

Linux Manjaro

Build details of Emacs from M-x emacs-version

GNU Emacs 27.1 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.22, cairo version 1.17.3) of 2020-08-28

C-h v cairo-version-string

1.17.3

C-h v system-configuration-features

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

Your font, and the ligature configuration you are using

The freeze happens with both Fantasque Sans Mono and Source Code Pro.

GUI or Terminal Emacs

GUI

[mickeynp]

@vale981, @Alexander-Miller,

Thank you for your bug reports. It seems this issue's most likely fixed for good in upstream Emacs.

[last-ent]

Turns out the issue was beacuse of pretty-mode.

Once I disabled/removed pretty-mode ligatures works like a charm!

[andyleejordan]

So this is strange. I was experiencing a similar issue where my Emacs was freezing (like in the linked reddit posts). I have HARFBUZZ and CAIRO and Cairo is at 1.16 and I'm using the latest emacs-27 branch on Ubuntu 20.04 with Cascadia Code. I manually bisected the list of ligatures I copied from the readme, and "=>" is the one that caused the freeze for me. Nothing else. Everything else is enabled and working properly, including "==>", which is weird! Sure enough though if I add that single ligature, freeze.

[mickeynp]

@andschwa, I suspect the issue is almost certainly due to a bug in Emacs 27.1. It's fixed in Emacs master (and definitely in the gccemacs branch also) so can you try it again in that one?

[andyleejordan]

I cherry-picked fe903c5ab7354b97f80ecf1b01ca3ff1027be446 on top of emacs-27 branch and that resolved my issue. However, commit 6f955a4 introduced an issue with the example configuration, as "\\" is seen as one character. I removed it and was able to load the example configuration.