fix(hir): preserve aliased native stream subclasses

[proggeramlug]

Summary

• resolve minified native constructor aliases to their original exports when lowering class heritage
• keep extends_name canonical so native stream super() initializes the already-allocated subclass instead of replacing it
• cover both class declarations and class expressions, including Claude Code's aliased Readable and EventEmitter shapes

Root cause

Claude Code's bundled readdirp imports Readable as ut and defines its stream as class V extends ut. Perry recognized ut as a native value, but heritage lowering matched only literal constructor names. It therefore used the dynamic-parent path; the native Readable constructor returned a replacement object and the derived _read implementation was lost. Canonicalizing the registered import export routes super() through the native subclass initializer and preserves the complete EventEmitter surface.

Verification

• cargo fmt --all --check
• cargo test --lib --bins -p perry-hir — 380 passed, 1 ignored
• cargo test --bins -p perry -- --skip codegen_env_vars_are_build_cache_inputs — 1,073 passed (the skipped invariant currently fails unchanged main because PERRY_CONCAT_SITE_CACHE is unclassified)
• scoped runtime phase — 3,068 passed, 4 ignored
• new Node/Perry differential fixture: byte-identical _read, prototype surface, and listener behavior
• extracted Claude Code 2.1.259 readdirp/chokidar chunk: watch-ready, with no uncaught TypeError
• existing userland readable-stream subclass differential remains byte-identical

No version bump.

Closes #9680

Summary by CodeRabbit

• Bug Fixes

  • Fixed startup errors affecting bundled stream-based watchers when native class imports are aliased or minified.
  • Preserved inherited stream and event-emitter functionality, including listener registration, event handling, and stream reads.

• Tests

  • Added regression coverage for aliased native stream and event-emitter subclasses.
  • Verified watcher behavior and inherited event-emitter methods.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Team

Run ID: 4734f45d-ca15-48ae-b701-ff3931857aaf

📥 Commits

Reviewing files that changed from the base of the PR and between 99e2b2b and f8e6771.

📒 Files selected for processing (4)

• changelog.d/9689-aliased-native-class-heritage.md
• crates/perry-hir/src/lower/tests.rs
• crates/perry-hir/src/lower_decl/class_decl.rs
• test-files/test_issue_9680_readdirp_stream_emitter_surface.ts

Included review availability: Your plan provides up to 8 included reviews per hour; 3 remain after this review.

---

📝 Walkthrough

Walkthrough

Class heritage lowering now resolves aliased native imports to canonical constructor names. Regression tests cover declaration and expression lowering, inherited stream and EventEmitter methods, and the documented startup error.

Changes

Aliased native class heritage

Layer / File(s)	Summary
Canonicalize native class parents crates/perry-hir/src/lower_decl/class_decl.rs	Native module bindings resolve to canonical exported names for class declarations and expressions. Native stream detection now accepts only valid classic stream bindings.
Validate aliased inheritance crates/perry-hir/src/lower/tests.rs, test-files/test_issue_9680_readdirp_stream_emitter_surface.ts, changelog.d/9689-aliased-native-class-heritage.md	Regression tests verify canonical heritage metadata and the inherited stream and EventEmitter APIs. The changelog records the fix.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Merge Risk: ⚪ Minimal · up to f8e67

Aliased native stream and EventEmitter subclasses now retain their expected inherited behavior, preventing the watcher startup TypeErrors. No current merge-readiness blocker remains.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 71.43% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 7 functions across 3 files. (1 skipped: 1…	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely describes the primary change: preserving aliased native stream subclasses during HIR lowering.
Description check	✅ Passed	The description provides the change summary, root cause, linked issue, verification results, test coverage, and version-bump status. It does not use every template heading or checklist item, but it is…
Linked Issues check	✅ Passed	The implementation addresses issue #9680 by canonicalizing aliased native constructors and preserving subclass initialization. The added tests verify the complete EventEmitter surface, stream behavior…
Out of Scope Changes check	✅ Passed	All changes are related to the linked issue and PR objectives. The HIR fix, regression tests, runtime fixture, and changelog entry support the aliased native stream subclass fix.

Full details: Docstring Coverage

Explanation

Docstring coverage is 71.43% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 7 functions across 3 files. (1 skipped: 1 unsupported.)

• Fix all pre-merge checks with AI

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands.}

[proggeramlug]

Landed via merge train #9694 (rebase-merge, authorship preserved).