Fix CI for latest rustc nightly#5152
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Nightly Rust as of 2026-05-06 no longer implicitly exports __heap_base/__data_end on wasm32-unknown-unknown. wasm-bindgen's threading post-processing requires __heap_base, so callers must now pass -Clink-arg=--export=__heap_base in RUSTFLAGS alongside the existing TLS exports. Updated: * Atomics CI job rustflags * CLI reference tests for atomics * nodejs-threads, raytrace-parallel, wasm-audio-worklet examples The flag is backward-compatible with older nightlies.
daxpedda
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May 8, 2026
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rust-lang/rust#156061 flipped the wasm `-Cpanic=unwind` default from legacy EH (try/catch) to modern (exnref) EH. Adjust CI and justfile so the legacy EH path now requires an explicit `-Cllvm-args=-wasm-use-legacy-eh` opt-in, while the unmarked `-Cpanic=unwind` invocations follow the new modern default. * legacy EH CI job now passes `-Cllvm-args=-wasm-use-legacy-eh` (Node 20 remains fine since legacy EH is still validated there). * exnref CI job drops the now-redundant `=false` opt-out and runs on Node 25 (modern EH needs V8 12.5+, i.e. Node 22.22.3+ or 24+). * test_native bumped from Node 20 to 24 because the cli termination tests build with `-Cpanic=unwind` and now emit modern EH wasm. * justfile: `test-wasm-bindgen-unwind` no longer needs the opt-out and `test-wasm-bindgen-unwind-eh` is renamed to `test-wasm-bindgen-unwind-legacy-eh` with the explicit legacy opt-in. TODOs noted in CI to drop modern-EH jobs back to Node 22 LTS once 22.22.3 ships on 2026-05-13.
`-Cpanic=unwind` now emits modern (exnref) EH by default. Document the runtime version requirement and how to opt into legacy EH for Node 20 compatibility.
Rename the Unreleased `Fixed` section to `Notices` (both entries are nightly toolchain compatibility heads-ups rather than wasm-bindgen bug fixes) and add an entry for rust-lang/rust#156061 flipping the wasm panic=unwind EH default to modern (exnref).
Node 24.14 (current setup-node '24' resolution) still hits the termination test failures; 24.15 is required for the cli termination tests to pass with modern EH wasm.
Earlier comments said "Node 24+" but 24.14 still fails the termination tests \u2014 24.15.0 is the actual minimum on the 24 line.
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This fixes CI on current nightly Rust (2026-05-06+) with two recent issues:
failed to find \__heap_base` for injecting thread id`.Use Node.js 24.15+ 22.22.3+
Node.js modern exception handling requires 22.22.3+ OR 24.15+.
We change the tests to use this version, and then explicitly turn on legacy exception handling for those tests.
Add --export=__heap_base for threading after rust-lang/rust#156174
rust-lang/rust#156174 (merged 2026-05-06) intentionally removed the implicit
__heap_base/__data_endexports onwasm*-unknown-unknownandwasm32v1-none, requiring threading toolchains like wasm-bindgen to opt in explicitly. The PR description spells out the required link arg directly:wasm-bindgen's threading post-processing needs__heap_base(seecrates/cli-support/src/transforms/threads/mod.rs:193) to set up per-thread stacks, so without the new export it bails immediately.This PR adds
-Clink-arg=--export=__heap_baseeverywhere the existing TLS exports are listed:.github/workflows/main.yml— atomics CI rustflagscrates/cli/tests/wasm-bindgen/reference.rs—runtest_targets_atomicsandno_duplicate_wasm_export_in_node_esm_atomics_debugexamples/nodejs-threads/package.jsonexamples/raytrace-parallel/package.jsonexamples/wasm-audio-worklet/package.jsonVerified locally: the fix makes the failing
headlesstest pass onnightly-2026-05-07(365c0e1d7), and remains backward-compatible with older nightlies (nightly-2026-05-06/e95e73209).