boa's parser and compiler recurse once per nesting level and have no limit of their own: about
100 nested parentheses in a field or document script overflowed a 2 MiB stack and aborted the
app, which `catch_unwind` can't stop. `printcraft_js::run` now:
- refuses a script longer than 256 KiB, or one that nests brackets more than 64 deep, chains
more than 64 prefix operators, or has more than 4096 `?`. Strings and comments are skipped.
The script fails with an error, as a syntax error would;
- runs the engine on its own thread with a 1 GiB stack, which is address space, committed only
as it's used. That covers every unbracketed construct a 256 KiB script can nest. A panic
inside the engine becomes a script error. On wasm the script still runs inline.
Regression tests: `deeply_nested_scripts_fail_instead_of_crashing`, which aborted the test
process before this change, and `ordinary_nesting_still_runs`.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
- js: `host()` returns a script error instead of panicking when the host state is missing.
- optimize, a11y: the graphics-state stack is read with `last`/`last_mut` instead of `expect`.
- fonts: the standard-14 ASCII map is built from `u8`, which can't fail.
- filters: zlib encoding into a `Vec` keeps the standard's narrow, documented `expect` exception.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Brandon Thomas