Merge train 184: #10212

[proggeramlug]

Merge train 184: lands #10212 (skip the unobservable exec lookup, keep small match scratch inline, copy ASCII captures in one pass; #10166) at head b96c44d2fa, plus the workspace version bump to 0.5.1558.

Both PR commits were cherry-picked onto 64f5249ac without conflicts. main has not moved since the PR's base, so the tree before the bump is byte-identical to the PR head.

Review: execute skips Get(R, "exec") only when is_valid_regex_ptr && regexp_view_uses_builtin, the same non-observable admission split's forward path uses. Inline match slots are charged to and released from the operation's MemoryBudget exactly as a heap buffer is. The ASCII capture copy reads the subject's ascii_bytes() under one view that neither allocates nor collects.

Instruction counts are on #10212 (perf stat instructions:u, per call, vs main): hoisted test −49.4 %, literal test −46.5 %, exec with captures −30.4 %, /g test −44.2 %, non-ASCII exec −2.9 %, non-ASCII exec loop −3.2 % per match. There are no regressions, and outputs match Node.

Local validation of this branch (perrymaster, Linux x86_64, --locked):

• cargo metadata --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: one warning outside the known global_this_webassembly.rs dead code. It is object/field_get_set/ic_miss/ic_slow.rs:544 ("value assigned to cache is never read"), which comes from main's own perf(codegen): collapse the generic property-get tower to two exits #10196 / generic property-get commits; this PR does not touch that file.
• cargo test -p perry-runtime --lib -- --test-threads=1: 3739 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: the same 12 approx_constant errors. Compared with train 181's warning diff, the only addition is that same ic_slow.rs warning from main.
• scripts/run_lint_gates.sh script tier: 76 of 77 pass. The failure is public benchmark evidence freshness, identical on main. gc_runtime_root_holders.py, check_file_size.sh and check_changeset_fragment.sh PerryTS/perry 10212 pass.

https://claude.ai/code/session_01Da12JXeG5XuVBma5yWp5C9

Summary by CodeRabbit

• Performance

  • Improved RegExp.prototype.test() and exec() performance for standard, unmodified regular expressions.
  • Reduced overhead for smaller match results by avoiding unnecessary allocations.
  • Improved handling of ASCII capture groups for faster match-result creation.
  • Preserved expected behavior when regular-expression methods or prototypes are customized.

• Release

  • Updated the documented and workspace version to 0.5.1558.

[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: 2eed7c7b-51ff-4aab-9ccf-e0aa0896b071

📥 Commits

Reviewing files that changed from the base of the PR and between 64f5249 and 8ff9373.

⛔ Files ignored due to path filters (1)

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

📒 Files selected for processing (10)

• CLAUDE.md
• Cargo.toml
• changelog.d/10212-regex-per-call.md
• crates/perry-runtime/src/gc/tests/runtime_roots/perex_dispatch.rs
• crates/perry-runtime/src/gc/tests/runtime_roots/perex_public.rs
• crates/perry-runtime/src/regex/perex_dispatch.rs
• crates/perry-runtime/src/regex/perex_memory.rs
• crates/perry-runtime/src/regex/perex_runtime.rs
• crates/perry-runtime/src/regex/perex_strings.rs
• scripts/gc_runtime_root_holders.json

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📝 Walkthrough

Walkthrough

The regex runtime now skips unobservable builtin exec lookups, stores small match data inline, and copies ASCII captures directly. Tests cover lookup observability, inline and heap capture storage, and ASCII and non-ASCII inputs. Project metadata records version 0.5.1558.

Changes

RegExp execution optimizations

Layer / File(s)	Summary
RegExp exec lookup dispatch crates/perry-runtime/src/regex/perex_dispatch.rs, crates/perry-runtime/src/gc/tests/runtime_roots/perex_dispatch.rs, scripts/gc_runtime_root_holders.json	Known builtin RegExp receivers bypass Get(receiver, "exec"). Other receivers retain override handling. Tests verify lookup behavior for builtin, overridden, reparented, and restored prototypes.
Inline match storage and capture validation crates/perry-runtime/src/regex/perex_memory.rs, crates/perry-runtime/src/regex/perex_runtime.rs, crates/perry-runtime/src/gc/tests/runtime_roots/perex_public.rs	Inline slots use memory-budget accounting. Larger buffers use heap storage. Capture tests cover inline slots, heap slots, unset groups, and ASCII or non-ASCII prefixes.
ASCII capture copying crates/perry-runtime/src/regex/perex_strings.rs	ASCII spans are copied directly as bytes after span and size checks. Non-ASCII spans use the existing unit-copy path.
Release metadata Cargo.toml, CLAUDE.md, changelog.d/10212-regex-per-call.md	The project version changes from 0.5.1557 to 0.5.1558. The changelog records the runtime optimizations.

Estimated code review effort: 3 (Moderate) | ~25 minutes

Change: Refactor

Sequence Diagram(s)

sequenceDiagram
  participant RegExpReceiver
  participant execute
  participant execOverride
  participant execute_with_resources
  RegExpReceiver->>execute: execute(receiver, input)
  alt known builtin receiver
    execute->>execute_with_resources: run builtin matcher
  else lookup required
    execute->>RegExpReceiver: Get(receiver, "exec")
    execute->>execOverride: handle override
    execOverride-->>execute: override result or builtin fallback
    execute->>execute_with_resources: run builtin matcher when no override applies
  end

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✨ 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 train184

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