A whole bunch of inline annotations, some of these were tracked down
with Instruments.app, others are guesses / just seemed right because
they were trivial wrapper functions.
Regardless, these changes are ultimately supported by improved vtebench
results on my machine (Apple M3 Max).
Powerline glyphs were treated as whitespace, giving the preceding cell a
constraint width of 2 and cutting off icons in people's prompts and
statuslines. It is however correct to not treat Powerline glyphs like
other Nerd Font symbols; they should simply be treated as normal
characters, just like their relatives in the block elements unicode
block.
This resolves
https://discord.com/channels/1005603569187160125/1417236683266592798
(never promoted to an issue, but real and easy to reproduce).
**Tip**
<img width="215" height="63" alt="Screenshot 2025-09-21 at 16 57 58"
src="https://github.com/user-attachments/assets/81e770c5-d688-4d8e-839c-1f4288703c06"
/>
**This PR**
<img width="215" height="63" alt="Screenshot 2025-09-21 at 16 58 42"
src="https://github.com/user-attachments/assets/5d2dd770-0314-46f6-99b5-237a0933998e"
/>
The constraint width logic was untested but contains some quite subtle
interactions, so I wrote a suite of tests covering the cases I'm aware
of.
While working on this code I also resolved a TODO comment to add all the
box drawing/block element type characters to the set of codepoints
excluded from the minimum contrast settings.
This also changes OSC strings to be null-terminated to ease lib-vt
integration. This shouldn't have any practical effect on terminal
performance, but it does lower the maximum length of OSC strings by 1
since we always reserve space for the null terminator.
Fixes various issues:
- C ABI detection was faulty, which caused some Zig programs to use
the C ABI mode and some C programs not to. Let's be explicit.
- Unit tests now tests C ABI mode.
- Build binary no longer rebuilds on any terminal change (a regression).
- Zig programs can choose to depend on the C ABI version of the terminal
lib by using the `ghostty-vt-c` module.
This makes it cleaner to add new sources of table generation and also
avoids inadvertently depending on different modules (despite Zig's lazy
analysis).
This also fixes up terminal to only use our look up tables which avoids
bringing ziglyph in for the terminal module.
Without this change, a phantom space appears after any character with
default emoji presentation that is converted to text with VS15. The only
other terminal I know of that respects variation selectors is Kitty, and
it walks the cursor back, which feels like the best choice, since that
way the behavior is observable (no way to know if the terminal supports
variation selectors otherwise without hard-coding that info per term)
and "dumb" programs like `cat` will output things correctly, and not
gain a phantom space after any VS15'd emoji.
