This PR builds on https://github.com/ghostty-org/ghostty/pull/9678 ~so
the diff from there is included here (it's not possible to stack PRs
unless it's a PR against my own fork)--review that one first!~
This PR updates the `graphemeBreak` calculation to use `uucode`'s
`computeGraphemeBreakNoControl`, which has [tests in
uucode](215ff09730/src/x/grapheme.zig (L753))
that confirm it passes the `GraphemeBreakTest.txt` (minus some
exceptions).
Note that the `grapheme_break` (and `grapheme_break_no_control`)
property in `uucode` incorporates `emoji_modifier` and
`emoji_modifier_base`, diverging from UAX #29 but matching UTS #51. See
[this comment in
uucode](215ff09730/src/grapheme.zig (L420-L434))
for details.
The `grapheme_break_no_control` property and
`computeGraphemeBreakNoControl` both assume `control`, `cr`, and `lf`
have been filtered out, matching the current grapheme break logic in
Ghostty.
This PR keeps the `Precompute.data` logic mostly equivalent, since the
`uucode` `precomputedGraphemeBreak` lacks benchmarks in the `uucode`
repository (it was benchmarked in [the original PR adding `uucode` to
Ghostty](https://github.com/ghostty-org/ghostty/pull/8757)). Note
however, that due to `grapheme_break` being one bit larger than
`grapheme_boundary_class` and the new `BreakState` also being one bit
larger, the state jumps up by a factor of 8 (u10 -> u13), to 8KB.
## Benchmarks
~I benchmarked the old `main` version versus this PR for
`+grapheme-break` and surprisingly this PR is 2% faster (?). Looking at
the assembly though, I'm thinking something else might be causing that.
Once I get to the bottom of that I'll remove the below TODO and include
the benchmark results here.~
When seeing the speedup with `data.txt` and maybe a tiny speedup on
English wiki, I was surprised given the 1KB -> 8KB tables. Here's what
AI said when I asked it to inspect the assembly:
https://ampcode.com/threads/T-979b1743-19e7-47c9-8074-9778b4b2a61e, and
here's what it said when I asked it to predict the faster version:
https://ampcode.com/threads/T-3291dcd3-7a21-4d24-a192-7b3f6e18cd31
It looks like two loads got reordered and that put the load that
depended on stage1 -> stage2 -> stage3 second, "hiding memory latency".
So that makes the new one faster when looking up the `grapheme_break`
property. These gains go away with the Japanese and Arabic benchmarks,
which spend more time processing utf8, and may even have more grapheme
clusters too.
### with data.txt (200 MB ghostty-gen random utf8)
<img width="1822" height="464" alt="CleanShot 2025-11-26 at 08 42 03@2x"
src="https://github.com/user-attachments/assets/56d4ee98-21db-4eab-93ab-a0463a653883"
/>
### with English wiki dump
<img width="2012" height="506" alt="CleanShot 2025-11-26 at 08 43 15@2x"
src="https://github.com/user-attachments/assets/230fbfb7-272d-4a2a-93e7-7268962a9814"
/>
### with Japanese wiki dump
<img width="2008" height="518" alt="CleanShot 2025-11-26 at 08 43 49@2x"
src="https://github.com/user-attachments/assets/edb408c8-a604-4a8f-bd5b-80f19e3d65ee"
/>
### with Arabic wiki dump
<img width="2010" height="512" alt="CleanShot 2025-11-26 at 08 44 25@2x"
src="https://github.com/user-attachments/assets/81a29ac8-0586-4e82-8276-d7fa90c31c90"
/>
TODO:
* [x] Take a closer look at the assembly and understand why this PR (8
KB vs 1 KB table) is faster on my machine.
* [x] _(**edit**: checking this off because it seems unnecessary)_ If
this turns out to actually be unacceptably slower, one possibility is to
switch to `uucode`'s `precomputedGraphemeBreak` which uses a 1445 byte
table since it uses a dense table (indexed using multiplication instead
of bitCast, though, which did show up in the initial benchmarks from
https://github.com/ghostty-org/ghostty/pull/8757 a small amount.)
AI was used in some of the uucode changes in
https://github.com/ghostty-org/ghostty/pull/9678 (Amp--primarily for
tests), but everything was carefully vetted and much of it done by hand.
This PR was made without AI with the exception of consulting AI about
whether the "Prepend + ASCII" scenario is common (hopefully it's right
about that being uncommon).
- Removes unnecessary marker constant from build.zig that existed
solely to signal build root status
- Uses filesystem check (@src().file access) instead of compile-time
declaration lookup to detect when ghostty is a dependency
- Same behavior with less indirection: file resolves from build root
only when ghostty is the main project
Detect if ghostty is being built as a dependency by comparing the build
root with ghostty's source directory. When used as a dependency, skip
git detection entirely and use the version from build.zig.zon.
This fixes build failures when downstream projects have git tags that
don't match ghostty's version format. Previously, ghostty would read
the downstream project's git tags and panic at Config.zig:246 with
"tagged releases must be in vX.Y.Z format matching build.zig".
Replace std.fs.accessAbsolute(b.pathFromRoot(...)) with
b.build_root.handle.access(...) since pathFromRoot can return
relative paths, but accessAbsolute asserts the path is absolute.
This fixes the VS16 issues found in this test:
https://ucs-detect.readthedocs.io/sw_results/ghostty.html#ghostty
This is also a more robust way to handle VS15/16 in general.
This commit also changes our propeties to be a packed struct which
reduces its size from 4 bytes to 1 and likewise drops our unicode table
size 4x.
This updates uucode. As part of this, the wcwidth implementation was
updated (in uucode) to make emoji modifiers width ZERO. But if they're
standalone, we want them as width 2.
So this also contains a change to force them as width 2 for our width
calculation. This only matters for standalone emoji modifiers, because
when they form a valid grapheme we don't use this width calculation.
This makes `libghostty-vt` build for freestanding wasm targets (aka a
browser) and produce a `ghostty-vt.wasm` file. This exports the same C
API that libghostty-vt does.
This commit specifically makes the changes necessary for the build to
build properly and for us to run the build in CI. We don't yet actually
try using it...
- update nixpkgs now that Zig 0.15.2 is available in nixpkgs
- drop hack that worked around compile failures on systems with more
than 32 cores
- enforce patch version of Zig
Resolves#8689
For various reason, ghostty wants to have a unique file extension for
the config files. The name was settled on `config.ghostty`. This will
help with tooling. See #8438 (original discussion) for more details.
This PR introduces the preferred default of `.ghostty` while still
supporting the previous `config` file. If both files exist, a warning
log is sent.
The docs / website will need to be updated to reflect this change.
> [!NOTE]
> Only tested on macOS 26.0.
---------
Co-authored-by: Mitchell Hashimoto <m@mitchellh.com>
