Merge train 210: CommonJS preamble cost cut by a third, copy-slot-hoists doc (v0.5.1588)

[proggeramlug]

This train lands #10349 and #10402 as v0.5.1588, on e6dcb6274d. Three source commits, each verified to preserve its patch-id and authorship.

• perf(cjs): cut the per-module CommonJS preamble cost by a third #10349 — the CommonJS wrapper preamble is emitted into every wrapped module, so its fixed cost is paid once per module in the dependency graph. Four changes cut it by a third on a 400-module fixture: 598,533 → 397,896 instructions per module. Chief among them, one createRequire instance per program instead of one per module.
• docs(gc): the copy-slot-hoists tests cover one hoist, not two (#10388) #10402 — corrects the copy_slot_hoists module doc. It claimed the copying minor hoists two facts per traced object; it hoists one. The old-generation fact is deliberately not hoisted, and the doc now records why: no sabotage of that hoist could be made to fail, because sticky dirty-page coverage carries an old→young edge independently of the remembered-set re-insertion the fact controls. A future hoist needs its own witness first.

Train repair

#10349's changelog fragment was keyed to the wrong PR. It shipped as changelog.d/10307-cjs-preamble-cost.md, but 10307-global-alias-member-read.md is already on main from the real #10307 (train 200). Different slug, so no collision — but fragments are PR-keyed so release notes trace back to the change, and two unrelated PRs sharing a 10307- prefix defeats that. Re-keyed to 10349-.

Validation

Validated head a9efe708d5. Five-package release build pinned and hash-verified, and re-verified after the gap run so nothing rebuilt underneath the fixtures.

• Crate suites: codegen 1571, runtime 3984, stdlib 139, hir 433, transform 137, cli 1139 — all green except main's one known runtime failure (gc::tests::heap_generation::a_free_or_move_outside_every_scope_is_caught_in_debug_builds).
• All nine preflight gates pass, including both raw-handle ratchet invocations, the holders gate, and the unrooted-local-shape check against main.
• Gap: filters require, cjs, module, import, weak, builtin. cjs and builtin are clean — cjs being the most direct filter for perf(cjs): cut the per-module CommonJS preamble cost by a third #10349.

Every red attributed

Six fixtures were A/B'd against main's own artifact set, and all six behave identically on both arms (node=1, main=0, train=0) with distinct build stamps asserted per arm, so neither can have fallen through to the wrong archives: test_issue_1723_require_stdlib_subnamespace, test_issue_764_state_at_module_init, test_issue_915_native_module_after_async_resume, test_perry_gc_module, test_dynamic_import_data_10104, test_issue_2656_weakref_finalization_gc. Perry is correct on both arms; node is what fails.

These were re-attributed from scratch rather than carried over from the previous train's identical verdicts. #10349 rewrites the per-module preamble, so every compiled program differs — a verdict measured on binaries that predate it says nothing about these. That distinction has already cost a re-run once in this queue.

The two remaining reds need no A/B: test_require is listed verbatim in run_parity_tests.sh's SKIP_TESTS on main (crypto.randomUUID() differs), and test_ramda_user_import is an ext-archive link refusal of the pinned five-package set, which is symmetric and environmental.

Note that --filter is a substring match over all fixtures, so these runs select test_issue_*/test_perry_* names that CI's gap suite (--filter test_gap_) never runs. Every test_gap_* fixture in scope passed.

Before merging, the pushed head and unchanged main are checked again. After merging, the rewritten commits are checked for preserved authorship and the main tree must match the validated train exactly.

Summary by CodeRabbit

• Performance

  • Improved CommonJS module loading efficiency, reducing fixed overhead for applications with many modules.
  • Reused shared module-loading resources across modules.

• Bug Fixes

  • Corrected builtin-module detection for certain node:-only module names.

• Maintenance

  • Updated the project version to 0.5.1588.
  • Updated validation coverage for the streamlined CommonJS module wrapper.

[coderabbitai]

Caution

Review failed

The pull request is closed.

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Advanced

Run ID: 31754257-ba57-466e-bb17-6d67ee71f55e

📥 Commits

Reviewing files that changed from the base of the PR and between e6dcb62 and a9efe70.

⛔ Files ignored due to path filters (1)

• Cargo.lock is excluded by !**/*.lock

📒 Files selected for processing (8)

• CLAUDE.md
• Cargo.toml
• changelog.d/10349-cjs-preamble-cost.md
• crates/perry-codegen/src/collectors/cjs_scaffolding.rs
• crates/perry-runtime/src/gc/tests/copy_slot_hoists.rs
• crates/perry/src/commands/compile/cjs_wrap/preamble_canary_tests.rs
• crates/perry/src/commands/compile/cjs_wrap/tests.rs
• crates/perry/src/commands/compile/cjs_wrap/wrap.rs

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📝 Walkthrough

Walkthrough

Changes

CommonJS preamble optimization

Layer / File(s)	Summary
Preamble generation and recognition crates/perry/src/commands/compile/cjs_wrap/wrap.rs, crates/perry-codegen/src/collectors/cjs_scaffolding.rs	The wrapper reuses a program-wide createRequire, uses isBuiltin, builds the module record as one object literal, removes redundant allocations, and recognizes the folded template.
Validation and release records crates/perry/src/commands/compile/cjs_wrap/*, crates/perry-runtime/src/gc/tests/copy_slot_hoists.rs, changelog.d/10349-cjs-preamble-cost.md, CLAUDE.md, Cargo.toml	Tests match the reduced preamble output. Documentation, changelog text, and version metadata were updated.

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

Change: Refactor

Suggested reviewers: jdalton

✨ Finishing Touches 💡 1

🛠️ Fix failing CI checks 💡

• Create stacked PR
• Commit on current branch

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch train210r

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