v0.5.1151 regression: codegen emits js_promise_report_unhandled_rejections but runtime doesn't export it — all native links fail

[proggeramlug]

Summary

Starting with v0.5.1151, every native link fails with an undefined symbol:

undefined reference to `js_promise_report_unhandled_rejections'
  >>> referenced by _main (perry_llvm_*.ll / .perry-cache/objects/<target>/<hash>.o : _main+0x9190)
Error: Linking failed

Codegen emits a call to js_promise_report_unhandled_rejections in the generated _main, but the linked perry_runtime/perry_stdlib does not define/export that symbol, so the link step fails for every program. This is a half-landed feature: the codegen side of the new "readable unhandled rejections" work shipped, the runtime symbol did not.

Almost certainly introduced by the v0.5.1151 unhandled-rejection changes:

• test(#4841): ... readable unhandled rejections + handled-rejection false-positive fix (#4852)
• fix(runtime): Promise static-method receiver + combinator/reflection/unhandled-rejection parity (#4838)

Regression window

• v0.5.1150 — OK. iOS / macOS / Linux native builds all linked & published.
• v0.5.1151 — broken. Same project, same config, all native targets fail at link with the symbol above.

Affected targets (confirmed in one release run)

Target	Result
aarch64-apple-ios	❌ undefined symbol _js_promise_report_unhandled_rejections
aarch64-apple-tvos	❌ undefined symbol _js_promise_report_unhandled_rejections
aarch64-apple-darwin (macOS)	❌ undefined symbol _js_promise_report_unhandled_rejections
x86_64-unknown-linux-gnu	❌ undefined reference js_promise_report_unhandled_rejections
*-linux-android	✅ links & publishes

Linux failing too rules out "stale Apple cross runtimes" (cf. #4856/#4859) as the whole story — the symbol is missing from the freshly auto-optimize-rebuilt runtime as well. The build log shows auto-optimize: rebuilding runtime+stdlib (panic=unwind, features=crypto) immediately before the link failure, i.e. the rebuilt runtime still lacks the symbol.

Reproduction

perry compile (release/publish) any program with perry 0.5.1151 for an Apple or Linux native target. Minimal _main is enough — the call is emitted unconditionally.

Observed in Bloom Jump release v1.0.106:

• macOS link failure (ld64.lld): https://github.com/Bloom-Engine/jump/actions/runs/27253240558/job/80481987617
• iOS: https://github.com/Bloom-Engine/jump/actions/runs/27253240558/job/80481987471
• tvOS: https://github.com/Bloom-Engine/jump/actions/runs/27253240558/job/80481987480
• Linux (clearest message, GNU ld): job 80481987522 in the same run

macOS excerpt

ld64.lld: error: undefined symbol: _js_promise_report_unhandled_rejections
>>> referenced by .perry-cache/objects/macos/5c4746fd0942737c.o:(symbol _main+0x9190)
Error: Linking failed
Error: Build error [INTERNAL_ERROR]: perry compile exited with code 1

Linux excerpt

perry_llvm_..._6.ll:(.text+0x9b573): undefined reference to `js_promise_report_unhandled_rejections'
Error: Linking failed

Expected

Either the runtime exports js_promise_report_unhandled_rejections (so the feature links), or codegen guards/omits the call until the runtime symbol is available.

Workaround

Pin to v0.5.1150.

[proggeramlug]

Reopening — the fix is incomplete and the symbol set grew

Built against v0.5.1159 (which includes #4883 "keep js_promise_report_unhandled_rejections alive through auto-optimize LTO"). All native targets still fail to link — and now with five undefined runtime symbols instead of one, on every native target (iOS, tvOS, macOS, Linux), each immediately after auto-optimize: rebuilding runtime+stdlib (panic=unwind, features=crypto):

undefined symbol: js_promise_run_promise_jobs
undefined symbol: js_register_closure_strict_function
undefined symbol: js_iterator_result_validate
undefined symbol: js_promise_report_unhandled_rejections   ← #4883 supposedly fixed this; still stripped
undefined symbol: js_mark_entry_module_esm

Root cause

The auto-optimize LTO rebuild of runtime+stdlib dead-strips a whole family of codegen-emitted runtime entrypoints. #4883 added a keep-alive anchor for exactly one of them, but:

1. The other four (js_promise_run_promise_jobs, js_register_closure_strict_function, js_iterator_result_validate, js_mark_entry_module_esm) have no anchor and are stripped.
2. js_promise_report_unhandled_rejections is still stripped here, so the fix(runtime): #4876 keep js_promise_report_unhandled_rejections alive through auto-optimize LTO #4883 anchor isn't surviving this LTO config (panic=unwind, features=crypto) — possibly the prebuilt cross-runtimes are stale, or the anchor isn't referenced from a retained root.

The keep-alive list (project_auto_optimize_keepalive_3320) needs every codegen-referenced runtime entrypoint, not a one-at-a-time allowlist — these are all called from generated _main/codegen and have no other in-runtime references, so each new one regresses the same way.

Regression window

• v0.5.1150 — native links clean (iOS/tvOS/macOS/Linux all green).
• v0.5.1151 — 1 symbol (js_promise_report_unhandled_rejections).
• v0.5.1159 — 5 symbols, all native targets.

Evidence

Bloom Jump release v1.0.107, run 27355233868 (jobs: iOS 80827608922, tvOS 80827608769, macOS 80827608778, Linux 80827608810). Identical symbol set on each, all gated behind the auto-optimize rebuild.

Ask

Anchor the full family through auto-optimize LTO (or exempt these runtime entrypoints from dead-strip). A reliable test: any program whose _main runs promise jobs + has a strict-mode closure should reproduce on a native target with auto-optimize enabled.