fix(runtime): permit catchable throw bridges to unwind

[proggeramlug]

Summary

• mark the unresolved-global and not-a-constructor throw bridges as C-unwind
• keep the generated-only unresolved-global anchor ABI in sync
• make the fix(compile): render lowering-error span (file:line:col + snippet) like check (#5249) #5253 regression harness surface child-process aborts

Release evidence

Release-candidate CI run 32988311861 reached issue_5253_construct_reference_source_location after the #5247 value-call tests passed. All four #5253 cases produced empty stdout because their child binaries aborted before the JavaScript catch handlers ran. Both failing runtime entry points were plain extern "C" even though they call js_throw; this applies the same direct-boundary fix validated by the preceding #5247 test.

Validation

• cargo fmt --all -- --check
• git diff --check
• compile-time extern "C-unwind" ABI guards

Release blocker for v0.5.1519.

Summary by CodeRabbit

• Bug Fixes
  • Improved error handling so constructor and unresolved-global errors can be caught reliably across runtime boundaries.
  • Enhanced test failure diagnostics with process status and captured output when compiled fixtures do not exit successfully.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: 9c94b121-20f8-4596-baec-8d0b722b228e

📥 Commits

Reviewing files that changed from the base of the PR and between 84ff806 and 746816f.

📒 Files selected for processing (3)

• changelog.d/8869-release-throw-abi.md
• crates/perry-runtime/src/error.rs
• crates/perry/tests/issue_5253_construct_reference_source_location.rs

Included review availability: Your plan provides up to 8 included reviews per hour; 7 remain after this review.

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📝 Walkthrough

Walkthrough

The runtime marks catchable unresolved-global and constructor errors as extern "C-unwind". Compile-time assertions verify both signatures. Fixture failures now include exit and process output diagnostics. A changelog entry documents the ABI behavior.

Changes

Runtime throw ABI

Layer / File(s)	Summary
Enable unwinding across runtime boundaries crates/perry-runtime/src/error.rs	The unresolved-global and not-a-constructor helpers use extern "C-unwind". Compile-time function-pointer assertions verify both signatures.
Validate fixture exits and document the change crates/perry/tests/issue_5253_construct_reference_source_location.rs, changelog.d/8869-release-throw-abi.md	Fixture execution asserts successful exit status and reports status, stdout, and stderr on failure. The changelog records the ABI behavior.

Estimated code review effort: 2 (Simple) | ~10 minutes

Merge Risk: ⚪ Minimal · up to 74681

The change allows specified runtime throw bridges to unwind catchably and strengthens regression-test failure reporting. No actionable merge-blocking risk remains beyond normal checks and review.

🚥 Pre-merge checks | ✅ 3 | ❌ 2

❌ Failed checks (2 warnings)

Check name	Status	Explanation	Resolution
Description check	⚠️ Warning	The description explains the runtime fix, affected functions, regression evidence, validation steps, and release impact. It does not follow the required template because it omits the Changes, Related …	Add the missing template sections. Include concrete changes under Changes, state an issue reference or "n/a" under Related issue, list verification commands and test results under Test plan, and complete the required Checklist.
Docstring Coverage	⚠️ Warning	Docstring coverage is 66.67% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 3 functions across 2 files. (1 skipped: 1…	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (3 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely describes the main runtime change: allowing catchable throw bridges to unwind.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

Full details: Description check

Explanation

The description explains the runtime fix, affected functions, regression evidence, validation steps, and release impact. It does not follow the required template because it omits the Changes, Related issue, Test plan, and Checklist sections.

Full details: Docstring Coverage

Explanation

Docstring coverage is 66.67% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 3 functions across 2 files. (1 skipped: 1 unsupported.)

• Fix all pre-merge checks with AI

✨ Finishing Touches 💡 1

📝 Generate docstrings 💡

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/release-r20-throw-abi

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