Claude CLI causing ghostty to crash and exit with SEGV

[ijdickinson]

Issue Description

Starting yesterday, running the claude CLI tool in a ghostty terminal causes the entire terminal process to crash and exit. This has high impact, because I'm currently running ghostty single-instance (I'm going to change this!), so all of my terminal sessions at the point of the crash exit. I'm on Ubuntu, I've just seen the note about running the debug build ... I haven't installed that yet but I will do so shortly.

Expected Behavior

Ghostty should not crash, not matter what control characters claude emits

Actual Behavior

SIGSEGV crashes multiple times per day, often within seconds of starting claude, sometimes later during a session.

Reproduction Steps

1. Start ghostty
2. Launch claude 2.1.282
3. Roughly 50% of the time, ghostty crashes with SIGSEGV and all current ghostty sessions terminae

Ghostty Logs

$ journalctl --user _COMM=ghostty --since "1 hour ago" --no-pager
Sep 25 08:00:51 sycamore com.mitchellh.ghostty[1172761]: info(font_shared_grid_set): font regular: Inconsolata
Sep 25 08:00:51 sycamore com.mitchellh.ghostty[1172761]: info(font_shared_grid_set): font bold: Inconsolata
Sep 25 08:00:51 sycamore com.mitchellh.ghostty[1172761]: info(font_shared_grid_set): font italic: Inconsolata
Sep 25 08:00:51 sycamore com.mitchellh.ghostty[1172761]: info(font_shared_grid_set): font bold_italic: Inconsolata
Sep 25 08:00:51 sycamore com.mitchellh.ghostty[1172761]: info(opengl): loaded OpenGL 4.6
Sep 25 08:00:51 sycamore com.mitchellh.ghostty[1172761]: info(font_shared_grid_set): font regular: Inconsolata
Sep 25 08:00:51 sycamore com.mitchellh.ghostty[1172761]: info(font_shared_grid_set): font bold: Inconsolata
Sep 25 08:00:51 sycamore com.mitchellh.ghostty[1172761]: info(font_shared_grid_set): font italic: Inconsolata
Sep 25 08:00:51 sycamore com.mitchellh.ghostty[1172761]: info(font_shared_grid_set): font bold_italic: Inconsolata
Sep 25 08:00:51 sycamore com.mitchellh.ghostty[1172761]: info(io_exec): found Ghostty resources dir: /snap/ghostty/current/share/ghostty
Sep 25 08:00:51 sycamore com.mitchellh.ghostty[1172761]: info(io_exec): shell integration automatically injected shell=.bash
Sep 25 08:00:51 sycamore com.mitchellh.ghostty[1172761]: warning(gtk_ghostty_application): unimplemented action=.cell_size
Sep 25 08:00:51 sycamore com.mitchellh.ghostty[1172761]: info(io_exec): started subcommand path=/bin/sh pid=2184771
Sep 25 08:01:57 sycamore com.mitchellh.ghostty[2186085]: info: ghostty version=1.3.1
Sep 25 08:01:57 sycamore com.mitchellh.ghostty[2186085]: info: ghostty build optimize=ReleaseFast
Sep 25 08:01:57 sycamore com.mitchellh.ghostty[2186085]: info: runtime=.gtk
Sep 25 08:01:57 sycamore com.mitchellh.ghostty[2186085]: info: font_backend=.fontconfig_freetype
Sep 25 08:01:57 sycamore com.mitchellh.ghostty[2186085]: info: dependency harfbuzz=11.0.0
Sep 25 08:01:57 sycamore com.mitchellh.ghostty[2186085]: info: dependency fontconfig=21402
Sep 25 08:01:57 sycamore com.mitchellh.ghostty[2186085]: info: renderer=renderer.generic.Renderer(renderer.OpenGL)
Sep 25 08:01:57 sycamore com.mitchellh.ghostty[2186085]: info: libxev default backend=io_uring
Sep 25 08:01:57 sycamore com.mitchellh.ghostty[2186085]: info(os_locale): setlocale from env result=C.UTF-8
Sep 25 08:01:57 sycamore com.mitchellh.ghostty[2186085]: info(gtk): GTK version build=4.14.5 runtime=4.14.5
Sep 25 08:01:57 sycamore com.mitchellh.ghostty[2186085]: info(gtk): libadwaita version build=1.5.0 runtime=1.5.0
Sep 25 08:01:57 sycamore com.mitchellh.ghostty[2186085]: info: reading configuration file path=/home/ian/.config/ghostty/config
Sep 25 08:01:57 sycamore com.mitchellh.ghostty[2186085]: info(config): default shell source=env value=/bin/bash
Sep 25 08:01:57 sycamore com.mitchellh.ghostty[2186085]: warning(gtk_ghostty_application): setting GDK_DEBUG=gl-disable-gles,gl-no-fractional,vulkan-disable
Sep 25 08:01:57 sycamore com.mitchellh.ghostty[2186085]: warning(gtk_ghostty_application): setting GDK_DISABLE=color-mgmt
Sep 25 08:01:57 sycamore com.mitchellh.ghostty[2186085]: warning(glib): WARNING: Gtk: Theme parser error: gtk.css:68:14-18: Expected a number
Sep 25 08:01:57 sycamore com.mitchellh.ghostty[2186085]: warning(glib): WARNING: Gtk: Theme parser error: gtk.css:1985:16-20: Expected a number
Sep 25 08:01:57 sycamore com.mitchellh.ghostty[2186085]: warning(glib): WARNING: Gtk: Theme parser error: gtk.css:2179:20-24: Expected a number
Sep 25 08:01:57 sycamore com.mitchellh.ghostty[2186085]: warning(glib): WARNING: Gtk: Theme parser error: gtk.css:2274:29-33: Expected a number
Sep 25 08:01:57 sycamore com.mitchellh.ghostty[2186085]: warning(glib): WARNING: Gtk: Theme parser error: gtk.css:2275:29-33: Expected a number
Sep 25 08:01:57 sycamore com.mitchellh.ghostty[2186085]: warning(glib): WARNING: Gtk: Theme parser error: gtk.css:2283:27-31: Expected a number
Sep 25 08:01:57 sycamore com.mitchellh.ghostty[2186085]: warning(glib): WARNING: Gtk: Theme parser error: gtk.css:2284:27-31: Expected a number
Sep 25 08:01:57 sycamore com.mitchellh.ghostty[2186085]: warning(glib): WARNING: Gtk: Theme parser error: gtk.css:2752:16-20: Expected a number
Sep 25 08:01:57 sycamore com.mitchellh.ghostty[2186085]: warning(glib): WARNING: Gtk: Theme parser error: gtk.css:2755:16-20: Expected a number
Sep 25 08:01:57 sycamore com.mitchellh.ghostty[2186085]: warning(glib): WARNING: Gtk: Theme parser error: gtk.css:2779:16-20: Expected a number
Sep 25 08:01:57 sycamore com.mitchellh.ghostty[2186085]: warning(glib): WARNING: Gtk: Theme parser error: gtk.css:3490:29-33: Expected a number
Sep 25 08:01:57 sycamore com.mitchellh.ghostty[2186085]: warning(glib): WARNING: Gtk: Theme parser error: gtk.css:3492:16-20: Expected a number
Sep 25 08:01:57 sycamore com.mitchellh.ghostty[2186085]: warning(glib): WARNING: Gtk: Theme parser error: gtk.css:3538:27-31: Expected a number
Sep 25 08:01:57 sycamore com.mitchellh.ghostty[2186085]: warning(glib): WARNING: Gtk: Theme parser error: gtk.css:3540:27-31: Expected a number
Sep 25 08:01:57 sycamore com.mitchellh.ghostty[2186085]: warning(glib): WARNING: Gtk: Theme parser error: gtk.css:3542:27-31: Expected a number
Sep 25 08:01:57 sycamore com.mitchellh.ghostty[2186085]: warning(glib): WARNING: Gtk: Theme parser error: gtk.css:3545:27-31: Expected a number
Sep 25 08:01:57 sycamore com.mitchellh.ghostty[2186085]: warning(glib): WARNING: Gtk: Theme parser error: gtk.css:3547:27-31: Expected a number
Sep 25 08:01:57 sycamore com.mitchellh.ghostty[2186085]: warning(glib): WARNING: Gtk: Theme parser error: gtk.css:4330:28-32: Expected a number
Sep 25 08:01:57 sycamore com.mitchellh.ghostty[2186085]: warning(glib): WARNING: Gtk: Theme parser error: gtk.css:4334:27-31: Expected a number
Sep 25 08:01:57 sycamore com.mitchellh.ghostty[2186085]: warning(glib): WARNING: Gtk: Theme parser error: gtk.css:4336:29-33: Expected a number
Sep 25 08:01:57 sycamore com.mitchellh.ghostty[2186085]: warning(glib): WARNING: Gtk: Theme parser error: gtk.css:4337:29-33: Expected a number
Sep 25 08:01:57 sycamore com.mitchellh.ghostty[2186085]: warning(glib): WARNING: Gtk: Theme parser error: gtk.css:4338:43-47: Expected a number
Sep 25 08:01:57 sycamore com.mitchellh.ghostty[2186085]: warning(glib): WARNING: Gtk: Theme parser error: gtk.css:4340:44-48: Expected a number
Sep 25 08:01:57 sycamore com.mitchellh.ghostty[2186085]: warning(glib): WARNING: Gtk: Theme parser error: gtk.css:4341:44-48: Expected a number
Sep 25 08:01:57 sycamore com.mitchellh.ghostty[2186085]: warning(glib): WARNING: Gtk: Theme parser error: gtk.css:4342:44-48: Expected a number
Sep 25 08:01:57 sycamore com.mitchellh.ghostty[2186085]: warning(glib): WARNING: Gtk: Theme parser error: style.css:140:17-19: Unexpected data at end of hsl() argument
Sep 25 08:01:57 sycamore com.mitchellh.ghostty[2186085]: info(font_shared_grid_set): font regular: Inconsolata
Sep 25 08:01:57 sycamore com.mitchellh.ghostty[2186085]: info(font_shared_grid_set): font bold: Inconsolata
Sep 25 08:01:57 sycamore com.mitchellh.ghostty[2186085]: info(font_shared_grid_set): font italic: Inconsolata
Sep 25 08:01:57 sycamore com.mitchellh.ghostty[2186085]: info(font_shared_grid_set): font bold_italic: Inconsolata
Sep 25 08:01:58 sycamore com.mitchellh.ghostty[2186085]: info(opengl): loaded OpenGL 4.6
Sep 25 08:01:58 sycamore com.mitchellh.ghostty[2186085]: info(font_shared_grid_set): font regular: Inconsolata
Sep 25 08:01:58 sycamore com.mitchellh.ghostty[2186085]: info(font_shared_grid_set): font bold: Inconsolata
Sep 25 08:01:58 sycamore com.mitchellh.ghostty[2186085]: info(font_shared_grid_set): font italic: Inconsolata
Sep 25 08:01:58 sycamore com.mitchellh.ghostty[2186085]: info(font_shared_grid_set): font bold_italic: Inconsolata
Sep 25 08:01:58 sycamore com.mitchellh.ghostty[2186085]: info(io_exec): found Ghostty resources dir: /snap/ghostty/current/share/ghostty
Sep 25 08:01:58 sycamore com.mitchellh.ghostty[2186085]: info(io_exec): shell integration automatically injected shell=.bash
Sep 25 08:01:58 sycamore com.mitchellh.ghostty[2186085]: warning(gtk_ghostty_application): unimplemented action=.cell_size
Sep 25 08:01:58 sycamore com.mitchellh.ghostty[2186085]: info(io_exec): started subcommand path=/bin/sh pid=2186205
Sep 25 08:02:29 sycamore com.mitchellh.ghostty[2186085]: info(font_codepoint_resolver): found codepoint 0x200A in fallback face=DejaVu Sans Mono
Sep 25 08:02:32 sycamore com.mitchellh.ghostty[2186085]: info(page_list): adjusting page capacity=.{ .cols = 120, .rows = 386, .styles = 128, .hyperlink_bytes = 192, .grapheme_bytes = 8192, .string_bytes = 2048 }
Sep 25 08:02:33 sycamore com.mitchellh.ghostty[2186085]: info(page_list): adjusting page capacity=.{ .cols = 120, .rows = 386, .styles = 128, .hyperlink_bytes = 192, .grapheme_bytes = 8192, .string_bytes = 2048 }
Sep 25 08:02:35 sycamore com.mitchellh.ghostty[2186085]: info(page_list): adjusting page capacity=.{ .cols = 120, .rows = 386, .styles = 128, .hyperlink_bytes = 192, .grapheme_bytes = 8192, .string_bytes = 2048 }
Sep 25 08:02:37 sycamore com.mitchellh.ghostty[2186085]: info(page_list): adjusting page capacity=.{ .cols = 120, .rows = 386, .styles = 128, .hyperlink_bytes = 192, .grapheme_bytes = 8192, .string_bytes = 2048 }
Sep 25 08:02:39 sycamore com.mitchellh.ghostty[2186085]: info(page_list): adjusting page capacity=.{ .cols = 120, .rows = 386, .styles = 128, .hyperlink_bytes = 192, .grapheme_bytes = 8192, .string_bytes = 2048 }
Sep 25 08:02:40 sycamore com.mitchellh.ghostty[2186085]: info(page_list): adjusting page capacity=.{ .cols = 120, .rows = 386, .styles = 128, .hyperlink_bytes = 192, .grapheme_bytes = 8192, .string_bytes = 2048 }
Sep 25 08:02:42 sycamore com.mitchellh.ghostty[2186085]: info(page_list): adjusting page capacity=.{ .cols = 120, .rows = 386, .styles = 128, .hyperlink_bytes = 192, .grapheme_bytes = 8192, .string_bytes = 2048 }
Sep 25 08:03:06 sycamore com.mitchellh.ghostty[2186085]: info(page_list): adjusting page capacity=.{ .cols = 120, .rows = 386, .styles = 128, .hyperlink_bytes = 192, .grapheme_bytes = 8192, .string_bytes = 2048 }
Sep 25 08:03:07 sycamore com.mitchellh.ghostty[2186085]: info(page_list): adjusting page capacity=.{ .cols = 120, .rows = 386, .styles = 128, .hyperlink_bytes = 192, .grapheme_bytes = 8192, .string_bytes = 2048 }
Sep 25 08:03:09 sycamore com.mitchellh.ghostty[2186085]: info(page_list): adjusting page capacity=.{ .cols = 120, .rows = 386, .styles = 128, .hyperlink_bytes = 192, .grapheme_bytes = 8192, .string_bytes = 2048 }
Sep 25 08:03:11 sycamore com.mitchellh.ghostty[2186085]: info(page_list): adjusting page capacity=.{ .cols = 120, .rows = 386, .styles = 128, .hyperlink_bytes = 192, .grapheme_bytes = 8192, .string_bytes = 2048 }
Sep 25 08:03:19 sycamore com.mitchellh.ghostty[2186085]: info(opengl): loaded OpenGL 4.6
Sep 25 08:03:19 sycamore com.mitchellh.ghostty[2186085]: info(io_exec): found Ghostty resources dir: /snap/ghostty/current/share/ghostty
Sep 25 08:03:19 sycamore com.mitchellh.ghostty[2186085]: info(io_exec): shell integration automatically injected shell=.bash
Sep 25 08:03:19 sycamore com.mitchellh.ghostty[2186085]: warning(gtk_ghostty_application): unimplemented action=.cell_size
Sep 25 08:03:19 sycamore com.mitchellh.ghostty[2186085]: info(io_exec): started subcommand path=/bin/sh pid=2187965
Sep 25 08:06:06 sycamore com.mitchellh.ghostty[2186085]: info(page_list): adjusting page capacity=.{ .cols = 120, .rows = 386, .styles = 128, .hyperlink_bytes = 192, .grapheme_bytes = 8192, .string_bytes = 2048 }
Sep 25 08:06:06 sycamore com.mitchellh.ghostty[2186085]: info(page_list): adjusting page capacity=.{ .cols = 120, .rows = 386, .styles = 128, .hyperlink_bytes = 192, .grapheme_bytes = 8192, .string_bytes = 2048 }
Sep 25 08:06:06 sycamore com.mitchellh.ghostty[2186085]: info(page_list): adjusting page capacity=.{ .cols = 120, .rows = 386, .styles = 128, .hyperlink_bytes = 192, .grapheme_bytes = 8192, .string_bytes = 2048 }
Sep 25 08:06:06 sycamore com.mitchellh.ghostty[2186085]: info(page_list): adjusting page capacity=.{ .cols = 120, .rows = 386, .styles = 128, .hyperlink_bytes = 192, .grapheme_bytes = 8192, .string_bytes = 2048 }
Sep 25 08:06:06 sycamore com.mitchellh.ghostty[2186085]: info(page_list): adjusting page capacity=.{ .cols = 120, .rows = 386, .styles = 128, .hyperlink_bytes = 192, .grapheme_bytes = 8192, .string_bytes = 2048 }
Sep 25 08:06:06 sycamore com.mitchellh.ghostty[2186085]: info(page_list): adjusting page capacity=.{ .cols = 120, .rows = 386, .styles = 128, .hyperlink_bytes = 384, .grapheme_bytes = 8192, .string_bytes = 2048 }
Sep 25 08:06:06 sycamore com.mitchellh.ghostty[2186085]: info(page_list): adjusting page capacity=.{ .cols = 120, .rows = 386, .styles = 128, .hyperlink_bytes = 384, .grapheme_bytes = 8192, .string_bytes = 2048 }
Sep 25 08:06:24 sycamore com.mitchellh.ghostty[2186085]: info(opengl): loaded OpenGL 4.6
Sep 25 08:06:24 sycamore com.mitchellh.ghostty[2186085]: info(io_exec): found Ghostty resources dir: /snap/ghostty/current/share/ghostty
Sep 25 08:06:24 sycamore com.mitchellh.ghostty[2186085]: info(io_exec): shell integration automatically injected shell=.bash
Sep 25 08:06:24 sycamore com.mitchellh.ghostty[2186085]: warning(gtk_ghostty_application): unimplemented action=.cell_size
Sep 25 08:06:24 sycamore com.mitchellh.ghostty[2186085]: info(io_exec): started subcommand path=/bin/sh pid=2190821
Sep 25 08:15:09 sycamore com.mitchellh.ghostty[2186085]: info(page_list): adjusting page capacity=.{ .cols = 120, .rows = 386, .styles = 128, .hyperlink_bytes = 384, .grapheme_bytes = 8192, .string_bytes = 2048 }
Sep 25 08:15:12 sycamore com.mitchellh.ghostty[2186085]: info(page_list): adjusting page capacity=.{ .cols = 120, .rows = 386, .styles = 128, .hyperlink_bytes = 384, .grapheme_bytes = 8192, .string_bytes = 2048 }
Sep 25 08:15:12 sycamore com.mitchellh.ghostty[2186085]: info(page_list): adjusting page capacity=.{ .cols = 120, .rows = 386, .styles = 128, .hyperlink_bytes = 384, .grapheme_bytes = 8192, .string_bytes = 2048 }
Sep 25 08:18:15 sycamore com.mitchellh.ghostty[2186085]: info(page_list): adjusting page capacity=.{ .cols = 120, .rows = 386, .styles = 128, .hyperlink_bytes = 384, .grapheme_bytes = 8192, .string_bytes = 2048 }
Sep 25 08:18:21 sycamore com.mitchellh.ghostty[2186085]: info(page_list): adjusting page capacity=.{ .cols = 120, .rows = 386, .styles = 128, .hyperlink_bytes = 384, .grapheme_bytes = 8192, .string_bytes = 2048 }
Sep 25 08:18:21 sycamore com.mitchellh.ghostty[2186085]: info(page_list): adjusting page capacity=.{ .cols = 120, .rows = 386, .styles = 128, .hyperlink_bytes = 384, .grapheme_bytes = 8192, .string_bytes = 2048 }
Sep 25 08:18:25 sycamore com.mitchellh.ghostty[2186085]: info(page_list): adjusting page capacity=.{ .cols = 120, .rows = 386, .styles = 128, .hyperlink_bytes = 384, .grapheme_bytes = 8192, .string_bytes = 2048 }
Sep 25 08:18:25 sycamore com.mitchellh.ghostty[2186085]: info(page_list): adjusting page capacity=.{ .cols = 120, .rows = 386, .styles = 128, .hyperlink_bytes = 384, .grapheme_bytes = 8192, .string_bytes = 2048 }
Sep 25 08:18:27 sycamore com.mitchellh.ghostty[2186085]: info(page_list): adjusting page capacity=.{ .cols = 120, .rows = 386, .styles = 128, .hyperlink_bytes = 384, .grapheme_bytes = 8192, .string_bytes = 2048 }
Sep 25 08:18:27 sycamore com.mitchellh.ghostty[2186085]: info(page_list): adjusting page capacity=.{ .cols = 120, .rows = 386, .styles = 128, .hyperlink_bytes = 384, .grapheme_bytes = 8192, .string_bytes = 2048 }
Sep 25 08:18:29 sycamore com.mitchellh.ghostty[2186085]: info(page_list): adjusting page capacity=.{ .cols = 120, .rows = 386, .styles = 128, .hyperlink_bytes = 384, .grapheme_bytes = 8192, .string_bytes = 2048 }
Sep 25 08:18:30 sycamore com.mitchellh.ghostty[2186085]: info(page_list): adjusting page capacity=.{ .cols = 120, .rows = 386, .styles = 128, .hyperlink_bytes = 384, .grapheme_bytes = 8192, .string_bytes = 2048 }
Sep 25 08:18:30 sycamore com.mitchellh.ghostty[2186085]: info(page_list): adjusting page capacity=.{ .cols = 120, .rows = 386, .styles = 128, .hyperlink_bytes = 384, .grapheme_bytes = 8192, .string_bytes = 2048 }
Sep 25 08:18:30 sycamore com.mitchellh.ghostty[2186085]: info(page_list): adjusting page capacity=.{ .cols = 120, .rows = 386, .styles = 128, .hyperlink_bytes = 768, .grapheme_bytes = 8192, .string_bytes = 2048 }

Ghostty Version

$ ghostty --version
Ghostty 1.3.1

Version
  - version: 1.3.1
  - channel: stable
Build Config
  - Zig version   : 0.15.2
  - build mode    : .ReleaseFast
  - app runtime   : .gtk
  - font engine   : .fontconfig_freetype
  - renderer      : renderer.generic.Renderer(renderer.OpenGL)
  - libxev        : io_uring
  - kernel version: 7.0.0-34-generic
  - desktop env   : other
  - GTK version   :
    build         : 4.14.5
    runtime       : 4.14.5
  - libadwaita    : enabled
    build         : 1.5.0
    runtime       : 1.5.0
  - libX11        : enabled
  - libwayland    : enabled

OS Version Information

Ubuntu 26.04.1

(Linux only) Display Server

Wayland

(Linux only) Desktop Environment/Window Manager

GNOME 50.1

Minimal Ghostty Configuration

I'm not sure this is ghostty config related

Additional Relevant Configuration

$ coredumpctl info 1172761 --no-pager
           PID: 1172761 (ghostty)
           UID: 1000 (ian)
           GID: 1000 (ian)
        Signal: 11 (SEGV)
     Timestamp: Fri 2026-09-25 08:01:28 BST (22min ago)
  Command Line: /snap/ghostty/820/bin/ghostty --gtk-single-instance=true --initial-window=false
    Executable: /snap/ghostty/820/bin/ghostty
 Control Group: /user.slice/user-1000.slice/user@1000.service/app.slice/snap.ghostty.ghostty-564ffb2a-ec12-4215-8a31-8ba323256d60.scope
          Unit: user@1000.service
     User Unit: snap.ghostty.ghostty-564ffb2a-ec12-4215-8a31-8ba323256d60.scope
         Slice: user-1000.slice
     Owner UID: 1000 (ian)
       Boot ID: 1357eb066f474f7792043e25de4face9
    Machine ID: 566cee456b9a454887dea6e83d673755
      Hostname: sycamore
       Storage: none
       Message: Process 1172761 (ghostty) of user 1000 terminated abnormally without generating a coredump.

I acknowledge that:

• I have reviewed the FAQ and confirm that my issue is NOT among them.
• I have searched the Ghostty documentation and confirm there doesn't exist a configuration option that solves my issue.
• I have searched the Ghostty repository (both open and closed Discussions and Issues) and confirm this is not a duplicate of an existing issue or discussion.
• I have checked the "Preview" tab on all text fields to ensure that everything looks right, and have wrapped all configuration and code in code blocks with a group of three backticks (```) on separate lines.

[calexandre]

Same here: Ubuntu 24.04.5, snap 1.3.1 (rev 820), GTK 4.14.5, Wayland, Intel GPU, Claude Code 2.1.293. It also happened with omp (oh-my-pi). Apport ignores snap binaries, so I have no core dump.

I think the snap has the same duplicate fontconfig @jcollie described in #14533. The snap's ghostty binary statically links fontconfig and exports 28 Fc* symbols, while pango, cairo and GTK load the snap's libfontconfig.so.1. Running LD_BIND_NOW=1 LD_DEBUG=bindings ghostty +version shows libpangoft2's fontconfig calls split between the two copies:

• to bin/ghostty: FcPatternCreate, FcPatternDestroy, FcFontMatch, FcConfigSubstitute, FcConfigDestroy, ...
• to libfontconfig.so.1: FcInit, FcPatternReference, FcFontSetSort, FcCharSetHasChar, ...

So pango can take a reference on a pattern with one copy and destroy it with the other. That would fit the free(): invalid pointer abort in #14533.

What fixed it for me: the pkgforge-dev AppImage of the same 1.3.1. Its ghostty defines no Fc* symbols and links libfontconfig.so.1, and the running process maps a single fontconfig. Five days of daily Claude Code and omp use with no crashes. That build also ships GTK 4.20.3, so it doesn't rule out GTK on its own.

For the snap: snap/snapcraft.yaml in this repo builds without -fsys=fontconfig, both at v1.3.1 and on main, and the edge snap (rev 984, 1.3.2-main+b699ea7) still exports the same 28 symbols. Building it with -fsys=fontconfig should leave a single copy. I haven't tested that build.

AI disclosure: Claude Code ran the symbol and binding checks and drafted this comment. I reviewed it before posting.

[jcollie]

Try building a snap from #14682

[ijdickinson]

I tried building a debug version from main head. Of course, at that point, the problem went away, so I have been unable to generate any more information on this problem. However, claude does seem to be stable now, so I've rebuilt an optimised binary and that's what I use day-to-day. Seems to have addressed the presenting problem, even if I don't fully understand what the root cause was.
From my pov, I'm happy for you to close this issue since I have an acceptable workaround.