fix(async): linearize await inside catch; complete the RegExp test262 worklist

[proggeramlug]

Lands #8707 and #8667.

#8707 — await inside catch compiled to a blocking busy-wait (fixes #8681)

build_async_catch_route_body_direct ignored catch_entry_state and re-inlined the catch body through rewrite_yield_to_await_in_stmts, turning every catch suspend back into a raw Expr::Await that codegen lowers as js_wait_for_event. Reached re-entrantly from the async-step cascade — a rejected awaited promise in a try routing to a catch that itself awaits, i.e. the ordinary stream retry/backoff shape — that blocking wait monopolises the single runtime thread while the driver that would resolve it sits suspended above it on the stack. The program deadlocks. This is the natively-compiled Claude Code -p streaming hang.

The revision also closes the await-in-finally gap that its own test caught. When I first validated this against main, async_generator_linearizes_every_await_position reported await-in-finally: 2 raw await(s) survived; it passed on the PR's own head, so it was an interaction with newer main, not a defect in the PR as written. The fix is that a linearized catch now takes the state-based upper bound (protected_end_state, which excludes the catch's own states), so an error raised inside the catch routes correctly. The legacy inline path (catch_entry_state == None) keeps the bound it always used. That test now passes on the merged result.

#8667 — complete the RegExp test262 worklist

Now rebases cleanly. I checked the Cargo.toml conflict I'd flagged as risky to union-resolve: the change is purely additive — regress gains features = ["utf16"], nothing dropped — and cargo check --locked still succeeds, so the lockfile is current and CI's locked build won't break.

One fix on top

#8707's new coverage pushed async_to_generator.rs to 2722 lines, past the file-size gate. computed_and_field_async_tests moved to a sibling file declared with #[path = "async_to_generator_tests.rs"], so the module path — and therefore every test name — is unchanged. Verified by running them: they still report as async_to_generator::computed_and_field_async_tests::*, 8/8. 2722 → 1806.

Validation (on the merged result)

• All 30 lint-job checkers pass
• perry-transform --lib: 92 passed, 0 failed (count unchanged across the split, so no test was lost)
• perry-runtime --lib (RUST_TEST_THREADS=1): 2657 passed, 0 failed (+2 from fix(runtime): complete RegExp test262 worklist #8667)
• perry-codegen --lib: 1214 passed, 0 failed
• cargo check --locked -p perry-runtime: clean
• Squashed tree verified identical to the validated tree

No version bump.

Summary by CodeRabbit

• Bug Fixes

  • Improved regular expression handling for quantified captures, nullable repetitions, and captures in lookarounds.
  • Preserved lone surrogate characters during regular expression replacement.
  • Fixed hangs caused by await inside catch blocks in async functions and generators.
  • Improved async-generator support for class methods, closures, and computed members.

• Tests

  • Added regression coverage for regular expression capture and replacement behavior.
  • Expanded async transformation coverage across supported syntax patterns.

[coderabbitai]

Caution

Review failed

The pull request is closed.

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: 7a11d4d2-9b68-4df8-856a-160ec0f19b3d

📥 Commits

Reviewing files that changed from the base of the PR and between 60f4fab and c1a77e5.

📒 Files selected for processing (10)

• changelog.d/8667-regexp-repeat-matcher.md
• changelog.d/8707-await-in-catch-blockwait.md
• crates/perry-runtime/Cargo.toml
• crates/perry-runtime/src/regex.rs
• crates/perry-runtime/src/regex/repeat_matcher.rs
• crates/perry-runtime/src/regex/tests.rs
• crates/perry-transform/src/async_to_generator.rs
• crates/perry-transform/src/async_to_generator_tests.rs
• crates/perry-transform/src/generator/lower/async_step.rs
• crates/perry-transform/src/generator/mod.rs

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📝 Walkthrough

Walkthrough

The PR updates regex matcher selection and WTF-8 replacement handling. It also records async generator methods and routes errors through linearized async catch states. Regression tests cover both runtime and transformation changes.

Changes

Regex matching and replacement

Layer / File(s)	Summary
Regex matcher selection crates/perry-runtime/src/regex/repeat_matcher.rs, crates/perry-runtime/src/regex/tests.rs	Negative lookaround captures now select the ECMAScript backtracking matcher. Tests cover negative lookahead capture behavior.
WTF-8 replacement flow crates/perry-runtime/Cargo.toml, crates/perry-runtime/src/regex.rs, crates/perry-runtime/src/regex/repeat_matcher.rs, crates/perry-runtime/src/regex/tests.rs, changelog.d/8667-regexp-repeat-matcher.md	Regex replacement preserves lone surrogates through UTF-16 and WTF-8 conversion. Replacement expansion supports captures and named groups.

Async generator transformation

Layer / File(s)	Summary
Async generator registration and transformation tests crates/perry-transform/src/generator/mod.rs, crates/perry-transform/src/async_to_generator.rs, crates/perry-transform/src/async_to_generator_tests.rs	Async generator methods and computed members record function IDs. Expanded tests validate await collection, linearization, closure rewriting, and nested async generators.
Linearized async catch dispatch crates/perry-transform/src/generator/lower/async_step.rs, changelog.d/8707-await-in-catch-blockwait.md	Linearized catches dispatch delivered errors to catch states. Throws raised inside catch bodies escape to enclosing handlers.

Estimated code review effort: 4 (Complex) | ~45 minutes

Sequence Diagram(s)

sequenceDiagram
  participant js_string_replace_regex
  participant replace_wtf8_subject
  participant regress
  js_string_replace_regex->>replace_wtf8_subject: pass WTF-8 subject and replacement
  replace_wtf8_subject->>regress: match UTF-16 or UCS-2 units
  regress-->>replace_wtf8_subject: return match captures
  replace_wtf8_subject-->>js_string_replace_regex: return WTF-8 replacement output

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sequenceDiagram
  participant async_step
  participant catch_dispatch
  participant async_step_loop
  async_step->>catch_dispatch: deliver error to linearized catch
  catch_dispatch->>async_step_loop: set catch_entry_state
  async_step_loop->>catch_dispatch: execute catch states
  catch_dispatch-->>async_step: propagate catch-raised throw

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Suggested reviewers: thehypnoo

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch merge/b20

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