Second pass over the page memory model (done by Codex/gpt-6-astra in an
isolated worktree, reviewed and merged here):
- Resize/reflow now port Zig's incremental ReflowCursor algorithm with
page backfill and the same capacity growth/split sequence, instead of
rebuilding a snapshot, so page boundaries, pruning and tracked-pin
remapping match Ghostty.
- Point<->pin conversion for the active area starts at the list tail and
the viewport offset is cached, so hot-path operations no longer walk
the whole scrollback from the head.
- RefCountedSet reproduces Zig's observable ID reuse and error points.
- All 202 PageList tests are ported (plus 13 extra regressions).
With this, the five Screen/Terminal tests previously ignored as blocked
on PageList behaviour pass and are re-enabled.
Test Plan:
- cargo test -p ghostty-terminal (913 passed, 0 ignored)
- cargo clippy -p ghostty-terminal --all-targets -- -D warnings
Ports ZIG/src/terminal/Terminal.zig - printing with grapheme clustering
and Unicode widths, wraparound, insert mode, charsets, cursor movement,
scroll regions and left/right margins, erase/insert/delete, tabs, modes,
alternate screens, save/restore cursor, DECALN, full reset, palette,
mouse/focus/paste flags, kitty keyboard, titles/pwd, semantic prompts,
hyperlinks, protected mode, synchronized output and resize.
stream_readonly.rs implements ghostty_vt::stream::Handler, applying all
state-changing actions to a Terminal and ignoring queries; it is the
base for termio's side-effecting handler. StringMap uses the onig crate
for Oniguruma-compatible regexes (needed by Ghostty's URL regex).
Not yet wired: kitty graphics (hooks and dirty flags are in place where
Zig calls into it, storage is being ported separately) and the tmux
control-mode viewer.
Test Plan:
- cargo test -p ghostty-terminal (849 passed, 5 ignored; all 372
Terminal and 33 stream_readonly tests ported; ignored ones are blocked
on the PageList parity pass)
Completes the font engine port:
- shaper/run.rs ports run.zig: the RunIterator over terminal rows that
splits text runs at style/face boundaries, selection and cursor,
handles graphemes and ligatures; Shaper::shape_run shapes a run.
- shared_grid_set.rs ports SharedGridSet.zig: grids keyed by a config
derived key, handed out as Arc<SharedGrid>.
- Font-related types now have one canonical definition in ghostty-config
(Variation, Descriptor, CodepointMap, metric modifiers, freetype load
flags, synthetic style, shaping break) which the font crate re-exports.
MetricModifier::apply_i32 now saturates to -i32::MAX like Zig.
- The 23 terminal-driven harfbuzz shaper tests are ported, printing via
Screen until Terminal lands.
Test Plan:
- cargo test -p ghostty-font (157 passed, 3 ignored - also skipped in
Zig); Devanagari/Chakma/Bengali tests return early without system fonts
- cargo test -p ghostty-config (255 passed)
Ports ZIG/src/terminal/{Screen,ScreenSet,Tabstops,Selection}.zig on top
of the page/PageList layer. The cursor holds a TrackedPin; Zig's cached
page_row/page_cell pointers become accessor methods. Selection methods
take the PageList explicitly because tracked bounds are handles.
Screen tests use minimal plain-text dump/selection-string helpers that
follow the formatter's semantics; they will delegate to the real
formatter once formatter.zig is ported.
Gaps found in the PageList layer are recorded for the parity pass in
docs/rewrite/notes/ghostty-terminal-pagelist-requests.md; three resize
tests are #[ignore]d pending those fixes (PageList::resize keeps
trailing blank rows Zig drops). Kitty image storage and StringMap are
placeholders.
Test Plan:
- cargo test -p ghostty-terminal (443 passed, 3 ignored; Screen 183/184,
Selection 18/18, Tabstops 4/5 - skipped tests use allocator failure
injection)
Ports the terminal-independent half of ZIG/src/renderer (OpenGL only):
- opengl/*: buffers, frames, pipelines, render passes, samplers,
targets, textures and the OpenGL GraphicsAPI backend on top of glow;
the GTK GLArea glue is replaced by a get_proc_address loader closure
- the GLSL shaders, copied verbatim and embedded; uniform/vertex structs
as bytemuck Pod types with std140 offsets asserted in tests
- shadertoy custom shaders converted with naga (GLSL in -> validate ->
GLSL 430 out) instead of glslang + spirv-cross
- size (screen/grid/cell/padding math), cursor style logic, backend
health, options and message types
The crate opts into unsafe_code = "deny"; unsafe glow calls live only in
opengl/gl.rs. A headless EGL integration test builds every pipeline and
the converted shadertoy shaders on Mesa and reads back rendered pixels.
Note: Zig's shadertoy Uniforms order the selection background/foreground
colors opposite to the GLSL block (likely an upstream bug); kept as in
Zig for parity and recorded in the notes.
Deferred to the next renderer pass: generic, cell, image, link, row,
State, Thread, Overlay (need terminal render state).
Test Plan:
- cargo test -p ghostty-renderer (33 tests incl. tests/egl_headless.rs)
Ports ZIG/src/apprt/{action,structs,surface,ipc,runtime}.zig into
ghostty-apprt: the Action enum performed by the core on the app runtime
(all 65 variants with docs), Target<S> generic over the runtime's
surface handle, clipboard/size/scale/selection structs, the core->surface
Message enum with a Mailbox over an AppMailbox trait, and IPC action
types for +new-window.
Owned Strings and Arc<Config> replace Zig's borrowed slices/pointers.
Scrollbar and RendererHealth are local stand-ins until core integration.
The embedded C API and browser runtime are out of scope.
Test Plan:
- cargo test -p ghostty-apprt (16 tests)
Ports ZIG/src/cli into ghostty-cli: action detection/dispatch with
per-action --help, and the actions help, version, list-actions,
list-colors, list-keybinds, list-themes (plain listing plus an
interactive ratatui browser mirroring Ghostty's libvaxis UI),
show-config, validate-config, edit-config, crash-report (listing),
ssh-cache and boo (235 embedded frames).
Verified byte-for-byte against the installed Ghostty 1.3.1 for stdout,
stderr and exit codes of most actions, incl. tty output in a pty at
widths 20-200. Known differences: +list-colors --plain prints all 782
colors (Ghostty truncates at 617 because it never flushes), +version
has placeholder build info until build_info::set is wired up.
Deferred: list-fonts, show-face (need font discovery integration) and
new-window (needs GTK IPC); they return NotYetAvailable for now.
Test Plan:
- cargo test -p ghostty-cli (86 tests)
- cargo run -p ghostty-cli --example cli -- +list-keybinds --plain
and diff against `ghostty +list-keybinds --plain`
Ports the rest of ZIG/src/font for the freetype/fontconfig/harfbuzz
backend: face loading and rasterization (synthetic bold/italic, color
emoji bitmaps, glyph constraints for nerd font icons), fontconfig
discovery, DeferredFace, Collection, CodepointResolver, CodepointMap,
SharedGrid, opentype table parsers, the nerd font attribute table, and
the harfbuzz shaper with feature parsing and shaping cache.
Embedded fonts (JetBrains Mono 2.304 variable, Symbols Nerd Font 3.4.0,
Noto emoji) and the test fonts from Ghostty live in res/ with their OFL/
MIT licenses.
The crate opts into unsafe_code = "deny"; FFI is confined to ft.rs,
fontconfig.rs and hb.rs with SAFETY comments. Glyph resampling uses an
stb-style resampler that is not bit-identical to stb.
Deferred to the next font pass (needs ghostty-terminal/config):
shaper/run.zig, SharedGridSet.zig and the 23 terminal-driven shaper
tests. Config-facing types are mirrored locally in config_types.rs.
Test Plan:
- cargo test -p ghostty-font (139 tests)
First cut of the terminal core memory model from ZIG/src/terminal:
size, point, style, hyperlink, ref_counted_set, page and PageList.
Design (see docs/rewrite/ARCHITECTURE.md decisions 2-4):
- Cell/Row are 8-byte u64 wrappers with Zig's exact bit offsets.
- Page owns row/cell Vecs plus style set, grapheme and hyperlink maps;
Page::layout reproduces Ghostty's byte-size formula on 64-bit Linux so
scrollback-limit pruning matches.
- PageList keeps nodes in a generation-checked slab with a free list and
list-owned tracked pins addressed by handles.
This is explicitly partial (docs/rewrite/notes/ghostty-terminal-
pagelist.md): 151/202 PageList tests ported; reflow rebuilds a snapshot
instead of Zig's incremental ReflowCursor; point<->pin conversion walks
from the list head (no active/viewport caches); RefCountedSet doesn't
reproduce probe-dependent ID reuse. A follow-up pass finishes parity.
Test Plan:
- cargo test -p ghostty-terminal (239 tests)
Ports the parts of Ghostty's IO layer that don't depend on the terminal:
- pty.zig: pty pair, window size, mode, child-side setsid/TIOCSCTTY;
master is CLOEXEC with IUTF8 set
- Command.zig: fork/execvpe with Ghostty's exact child setup (stdio
dup2, best-effort chdir, rlimit restore, os/runtime pre-exec hooks,
cgroup handling) and exit status decoding
- shell_integration.zig for bash/zsh/fish/elvish/nushell plus feature
flags; scripts copied verbatim to resources/shell-integration/
- terminfo generator for xterm-ghostty, byte-identical to Zig's encode
output (golden file produced with the real Zig code)
This crate opts into unsafe_code = "deny" (fork/exec need it) with
allow + SAFETY comments on minimal items.
Integration left: config-derived option types are local stand-ins;
cgroup D-Bus scope creation is a closure hook; Exec/Termio/Thread/
stream_handler wait for ghostty-terminal. Pty now closes both fds on
drop (Zig never auto-closed the slave) - to re-check when wiring Exec.
Test Plan:
- cargo test -p ghostty-termio (52 tests, incl. real pty spawn test
expecting "hi\r\n31 97\r\n" from `echo hi; stty size`)
Ports ZIG/src/config (minus C/WASM APIs) and cli/{args,CommaSplitter,
diagnostics}.zig into ghostty-config:
- all 202 options with exact names, types, defaults and verbatim docs,
declared through one config_struct! macro; Zig's comptime reflection is
replaced by the ConfigField/CliTarget traits
- loading: default XDG files, -e, config-file includes (optional '?',
cycle detection), themes incl. light:/dark: pairs, conditional config,
replay, finalize() derived defaults, clone/changed diffing for reload
- Linux/GTK default keybinds built on ghostty_input::binding::Set
- formatter producing +show-config output
Verified against the installed Ghostty 1.3.1: `+show-config --default`
and `--default --docs` match byte for byte (except gtk-opengl-debug,
which differs between debug/release builds), as do two complex loaded
configs.
Open items (docs/rewrite/notes/ghostty-config.md): url regex needs an
Oniguruma-compatible engine (onig) in the renderer; some font/terminal
types are local copies awaiting integration; KeyRemapSet equality is
order sensitive unlike Zig.
Test Plan:
- cargo test -p ghostty-config (255 tests)
- compare `ghostty +show-config --default --docs` with our formatter
Ports ZIG/src/terminal/stream.zig: the Stream feeds bytes through the
UTF-8 decoder and parser and dispatches every CSI/ESC/OSC/DCS/APC and
C0/C1 control to a Handler as a high-level Action (all 95 Zig
variants). Zig's comptime handler interface becomes a Handler trait with
an associated error type, a required vt() and an optional vt_raw() hook.
Performance: next_slice() processes 4 KiB chunks, finds ESC with memchr
and decodes printable runs in bulk (scalar port of ZIG/src/simd's
index_of / utf8_decode_until_control_seq), plus the CSI parameter fast
path.
Terminals must construct the stream with Stream::new_alloc so the OSC
parser accepts allocating commands (colors, OSC 133), as in Zig.
Minor differences: after a stray UTF-8 byte the rest of the chunk
returns to the fast path, and a spurious Zig warning after CSI 2/5 W is
dropped.
Test Plan:
- cargo test -p ghostty-vt (448 passed; 37/38 stream tests ported,
the skipped one only exercises the C ABI)
Ports ZIG/src/input (except macOS keymaps) into ghostty-input:
- key, key_mods (incl. RemapSet), the physical keycode table
- key_encode: legacy, modifyOtherKeys and kitty keyboard protocol
encoders, function key tables
- Binding: all keybinding actions with their user-visible docs (for
+list-actions), triggers, sets with sequences, chains, leader keys and
key tables, and formatting back to config strings
- command palette defaults, mouse, paste safety checks, kitty helpers,
links, helpgen action docs
Deviations (docs/rewrite/notes/ghostty-input.md): Mods.super is named
super_; case folding uses char::to_lowercase plus Ghostty's special
cases instead of uucode tables; chain parents are trigger paths instead
of pointers; a Zig bug where chained leaves inside sequences corrupted the
shared prefix when formatting is fixed (covered by a test).
Integration left: building encode/paste Options from terminal modes,
and implementing the EntryFormatter trait in ghostty-config.
Test Plan:
- cargo test -p ghostty-input (220 tests; 8 macOS-only skipped)
- cargo clippy -p ghostty-input --all-targets -- -D warnings
ghostty-unicode: Ghostty computes codepoint properties with the uucode
Zig package (v0.2.0, Unicode 17.0.0). There is no Rust equivalent, so
a trimmed UCD set is vendored in ucd/ and build.rs re-implements
uucode's derivations: cell width rules incl. Ghostty's overrides for
emoji modifiers and Prepend, grapheme break classes with the
compile-time grapheme_break state table, the is_symbol set, and emoji
presentation. Lookups are three array indexes per codepoint. Validated
against the official GraphemeBreakTest.txt.
ghostty-datastruct: split_tree (used for GTK splits; f16 ratios so
rounding and debug diagrams match Zig), circ_buf, lru, cache_table,
blocking_queue, segmented_pool, message_data, comparison,
array_list_collection. intrusive_linked_list is not needed (lru is
index based). lru now reports the evicted (old) key, Zig reported the
new key, which appears to be a bug.
Not yet covered: case_folding_full (needed by input bindings).
Test Plan:
- cargo test -p ghostty-unicode (16) -p ghostty-datastruct (88)
- cargo clippy for both crates with -D warnings
Ports ZIG/src/os for Linux into ghostty-os: XDG dirs, home dir, hostname,
env/PATH helpers, passwd lookup (via nix), shell detection, resources
dir discovery, string encodings (printf-q, URL percent), systemd
sd_notify, i18n via gettextrs, xdg-open, desktop/cgroup/kernel info,
temp dirs, URI parsing (port of std.Uri incl. Ghostty's extra options),
and a zbus-based Flatpak HostCommand implementation.
The crate stays free of unsafe. Consequences, all tracked as
TODO(integration) in docs/rewrite/notes/ghostty-os.md:
- locale::ensure_locale is a no-op (setlocale/setenv are unsafe; GTK
calls setlocale itself); setenv/unsetenv are not exposed.
- passwd's Flatpak branch needs the termio pty and falls back to the
sandbox entry for now.
- FlatpakHostCommand's D-Bus path is untested (no portal here).
Intentional fix: a leading '@' in NOTIFY_SOCKET is treated as an
abstract socket.
macOS/Windows/WASM modules are out of scope.
Test Plan:
- cargo test -p ghostty-os (88 tests)
- cargo clippy -p ghostty-os --all-targets -- -D warnings
Ports ZIG/src/font/{Metrics,Atlas,Glyph}.zig and the whole sprite font
(font/sprite/**): box drawing, block elements, braille, branch/git
graph symbols, geometric shapes, powerline, and the symbols for legacy
computing (+ supplement, incl. the octants table).
Ghostty draws sprites with z2d; we use tiny-skia for path coverage,
composited onto an alpha8 canvas, while following the Zig geometry
(positions, thickness, rounding). Comptime discovery of draw functions
is replaced by explicit, overlap-checked codepoint range tables.
Upstream reference sheets are vendored in testdata/ and compared with a
tolerance: braille and U+1CD00 are pixel-identical; other sheets differ
only in antialiasing on thin diagonals/curves. Review renders are written
to target/sprite_sheets/.
The crate temporarily drops its config/unicode/terminal deps until the
rest of the font engine is ported (Phase 3).
Test Plan:
- cargo test -p ghostty-font (49 tests incl. reference sheet comparison)
- inspect target/sprite_sheets/review-all-18x36.png
Ports the parsing half of ZIG/src/terminal into the ghostty-vt crate:
- Parser state machine with a compile-time generated parse table and
the UTF-8 decoder
- OSC parser incl. all sub-parsers (titles, colors, clipboard, hyperlinks,
semantic prompts/OSC 133, OSC 9 / ConEmu, iTerm2, kitty clipboard,
color and text-sizing protocols, context signals)
- CSI, SGR, modes table with save/restore, charsets, ansi, device status,
mouse shapes, APC, DCS (incl. XTGETTCAP), tmux control-mode parser
- color palette / X11 color names, kitty color and graphics command parser
Deviations from Zig (documented in docs/rewrite/notes/ghostty-vt-W*.md):
parser actions own their payloads instead of borrowing parser buffers;
OSC strings are Vec<u8>; non-exhaustive Zig enums gain an Other(raw)
variant; tmux regexes replaced by equivalent hand-written matchers.
Known follow-up: semantic_prompt.rs carries local copies of the printf-q
and percent decoders that belong in ghostty-os.
Test Plan:
- cargo test -p ghostty-vt: 395 passed, 1 ignored (skipped in Zig too)
- cargo clippy -p ghostty-vt --all-targets -- -D warnings: clean
Start of the full Rust rewrite of Ghostty 1.3.1 (reference source in
../ghostty). Sets up a workspace whose crates mirror Ghostty's Zig modules
(vt, unicode, datastruct, os, input, config, terminal, font, renderer,
termio, core, apprt-gtk) so porting work can proceed in parallel per crate.
Also adds:
- docs/rewrite/{ARCHITECTURE,PLAN,STATUS,AGENT_GUIDE}.md: crate map, core
design decisions (safe Rust, slab-based PageList, logical capacity
accounting), phased plan, progress tracker, and porting rules.
- Workspace clippy config relaxing pedantic lints that are pure noise for
low-level terminal code (casts, long functions).
- Shared vt types needed by several work packages up front: kitty
keyboard flags (kitty/key.rs) and the CSI separator bitset (SepList).
Test Plan:
- cargo test -p ghostty-vt (3 tests pass)
- cargo clippy -p ghostty-vt --all-targets -- -D warnings
ddidderr