Merge train 182: #10205

[proggeramlug]

Merge train 182: lands #10205 (JS-level regex searches on non-ASCII strings resume from the previous call's position, via a per-thread heap generation; part of #10164 and #10165) at head d04e162ba1, plus the workspace version bump to 0.5.1555.

Both PR commits were cherry-picked onto 5d3bf85f9 without conflicts. main has not moved since the PR's base, so the tree before the bump is byte-identical to the PR head, and the PR head's validation applies unchanged.

Validation on that tree (perrymaster, Linux x86_64, --locked):

• cargo fmt --all -- --check
• cargo check -p perry-runtime --no-default-features --features full --lib (regex feature off): 0 warnings
• cargo check -p perry-runtime --lib --tests: no warnings outside the known global_this_webassembly.rs dead code
• cargo test -p perry-runtime --lib -- --test-threads=1: 3724 passed, 1 failed. The failure is native_stack::tests::stack_top_respects_custom_thread_stack_sizes, red on main.
• cargo clippy -p perry-runtime --lib --tests: identical to train 181
• scripts/run_lint_gates.sh script tier: 76 of 77 pass. The failure is public benchmark evidence freshness, identical on main.
• check_changeset_fragment.sh PerryTS/perry 10205: pass

Re-checked on this branch after the bump: cargo metadata --locked, fmt, gc_runtime_root_holders.py, check_file_size.sh.

The PR has the tests, the 13 fault injections (all fail as required) and the measurements. The non-ASCII exec loop at 40,000 records drops from 28.5 s to 314 ms, and matchAll from 26.9 s to 463 ms. ASCII per-call cost rises by 27–55 instructions (0.1–0.2 %).

https://claude.ai/code/session_01Da12JXeG5XuVBma5yWp5C9

Summary by CodeRabbit

• Performance

  • Improved JavaScript regular expression loops over non-ASCII text, preventing repeated searches from becoming quadratic.
  • exec() and matchAll() can now resume searches more efficiently across calls.

• Bug Fixes

  • Corrected regex position reuse when strings are moved or replaced during garbage collection, ensuring searches start from the correct location.

• Documentation

  • Updated the documented release version to 0.5.1555.
  • Added changelog coverage for the regex performance improvement.

[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: e299e82e-3a07-4837-a426-576e3b08e2c3

📥 Commits

Reviewing files that changed from the base of the PR and between 5d3bf85 and 6eb609e.

⛔ Files ignored due to path filters (1)

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

📒 Files selected for processing (28)

• CLAUDE.md
• Cargo.toml
• changelog.d/10205-regex-cross-call-position.md
• crates/perry-runtime/src/arena/promote.rs
• crates/perry-runtime/src/arena/reset.rs
• crates/perry-runtime/src/arena/tests.rs
• crates/perry-runtime/src/gc/copying.rs
• crates/perry-runtime/src/gc/cycle.rs
• crates/perry-runtime/src/gc/heap_generation.rs
• crates/perry-runtime/src/gc/malloc.rs
• crates/perry-runtime/src/gc/mod.rs
• crates/perry-runtime/src/gc/old_free.rs
• crates/perry-runtime/src/gc/oldgen.rs
• crates/perry-runtime/src/gc/tests/alloc.rs
• crates/perry-runtime/src/gc/tests/debt_pacer.rs
• crates/perry-runtime/src/gc/tests/evacuation.rs
• crates/perry-runtime/src/gc/tests/heap_generation.rs
• crates/perry-runtime/src/gc/tests/incremental_sweep_reclaim.rs
• crates/perry-runtime/src/gc/tests/mod.rs
• crates/perry-runtime/src/gc/tests/oldgen.rs
• crates/perry-runtime/src/gc/tests/promote_in_place.rs
• crates/perry-runtime/src/gc/tests/runtime_roots.rs
• crates/perry-runtime/src/gc/tests/runtime_roots/perex_position_hint.rs
• crates/perry-runtime/src/gc/tests/runtime_roots/perex_reuse.rs
• crates/perry-runtime/src/regex.rs
• crates/perry-runtime/src/regex/perex_api.rs
• crates/perry-runtime/src/regex/perex_position_hint.rs
• scripts/gc_runtime_root_holders.json

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📝 Walkthrough

Walkthrough

Changes

Regex position reuse and heap identity

Layer / File(s)	Summary
Heap-generation contract crates/perry-runtime/src/gc/heap_generation.rs, crates/perry-runtime/src/gc/mod.rs	Adds per-thread heap generations, scoped HeapChange tracking, event kinds, and debug assertions.
GC change instrumentation crates/perry-runtime/src/arena/*, crates/perry-runtime/src/gc/{copying.rs,cycle.rs,malloc.rs,old_free.rs,oldgen.rs}	GC paths now open or validate heap-change scopes for memory movement, reclamation, sweeping, promotion, compaction, and reallocation.
Heap-generation validation crates/perry-runtime/src/arena/tests.rs, crates/perry-runtime/src/gc/tests/*	Tests cover generation advancement, event counts, scope assertions, and the instrumented GC paths.
Regex position hint flow crates/perry-runtime/src/regex.rs, crates/perry-runtime/src/regex/perex_api.rs, crates/perry-runtime/src/regex/perex_position_hint.rs	Adds a four-entry per-thread hint cache and uses validated string identities to look up and record regex search positions.
Regex validation and release support crates/perry-runtime/src/gc/tests/runtime_roots/*, scripts/gc_runtime_root_holders.json, changelog.d/10205-regex-cross-call-position.md, Cargo.toml, CLAUDE.md	Tests verify linear loops and reject stale hints after movement or address reuse. Release metadata, changelog text, and runtime-root records are updated.

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

Change: Bug fix · Severity of issue fixed: Medium

Sequence Diagram(s)

sequenceDiagram
  participant JavaScript
  participant RegexExecution
  participant PositionHint
  participant GarbageCollector
  JavaScript->>RegexExecution: execute repeated non-ASCII search
  RegexExecution->>PositionHint: look up string identity
  PositionHint-->>RegexExecution: return prior position when valid
  RegexExecution->>GarbageCollector: continue with possible collection
  GarbageCollector->>PositionHint: invalidate identity through generation change
  RegexExecution->>PositionHint: record post-search position

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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 train182

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