fix(runtime): honor exotic indices in Array reverse (rebase of #8400)

[proggeramlug]

Summary

Rebase of #8400 onto current main. Original work by @proggeramlug; this exists only
because that branch conflicts with main and is on a fork I cannot push to.

Completes the remaining Array.prototype.reverse cluster from #5898: arrays with holes,
indexed descriptors, or indexed prototype properties now follow the specified live
HasProperty / Get / Set / Delete order, with the receiver and both observed values
rooted across accessors.

The conflict, and how it was resolved

crates/perry-runtime/src/array/mod.rs conflicts on a re-export list. Resolved as a
union, not by taking either side:

• main had gained array_object_flags_resolved and
  canonicalize_array_numeric_store_value_from_flags from perf(codegen): elide proven element shape checks #8414
• the original branch adds array_named_property_delete_by_name

Taking the PR's side wholesale would have silently dropped the two #8414 symbols. All three
are present here.

Validation

• perry-runtime --lib — 2599 passed
• perry --bin perry — 1005 passed
• issue_5898_array_reverse_exotic — 1 passed
• scripts/run_lint_gates.sh — all 50 gates
• 19/19 sweep corpus byte-exact against the Node oracle

Behaviour on the test262 shape matches Node exactly:

before: 1=onproto has1=true
after:  0=3 1=onproto 2=1 own1=false

Holes, dense arrays and accessor-backed indices also match.

Supersedes #8400.

Summary by CodeRabbit

• Bug Fixes

  • Fixed Array.prototype.reverse behavior for inherited, accessor-backed, sparse, deleted, and other unusual array indices.
  • Corrected array length truncation so non-configurable elements are preserved and reported correctly.
  • Prevented deleted sparse elements from reappearing after arrays grow.
  • Improved handling of getters and side effects during array reversal.

• Tests

  • Added regression coverage for exotic, sparse, inherited, and dynamically modified arrays.

[coderabbitai]

Caution

Review failed

The pull request is closed.

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: c36eb00d-6896-40aa-a258-0276ad41f93a

📥 Commits

Reviewing files that changed from the base of the PR and between 9051d3f and 2cc38d4.

📒 Files selected for processing (6)

• changelog.d/8400-array-reverse-exotic-indices.md
• crates/perry-runtime/src/array/concat_reverse.rs
• crates/perry-runtime/src/array/header.rs
• crates/perry-runtime/src/array/mod.rs
• crates/perry-runtime/src/array/push_pop.rs
• crates/perry/tests/issue_5898_array_reverse_exotic.rs

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📝 Walkthrough

Walkthrough

Array.prototype.reverse now uses specification-ordered property operations for exotic arrays and keeps the dense-array fast path. Array truncation and deletion now clear sparse and descriptor-backed indices correctly. Regression tests cover inherited indices, accessors, sparse arrays, and GC-related storage cleanup.

Changes

Array reverse and indexed mutation

Layer / File(s)	Summary
Indexed deletion and truncation crates/perry-runtime/src/array/header.rs, crates/perry-runtime/src/array/mod.rs, crates/perry-runtime/src/array/push_pop.rs	Named-property deletion is available by string name. Truncation now deletes indices in descending order and preserves length when deletion fails. Deletion clears both dense and sparse representations.
Spec-driven exotic reversal crates/perry-runtime/src/array/concat_reverse.rs	js_array_reverse routes arrays with holes, inherited indices, or accessors through live presence checks, reads, writes, and deletes. Dense arrays retain direct slot swapping.
Regression coverage and changelog crates/perry/tests/issue_5898_array_reverse_exotic.rs, changelog.d/8400-array-reverse-exotic-indices.md	The integration test covers inherited indices, getter side effects, sparse truncation, GC rekeying, and deletion cleanup. The changelog documents the changes.

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

Sequence Diagram(s)

sequenceDiagram
  participant Array.prototype.reverse
  participant reverse_array_spec_path
  participant Array indexed properties
  Array.prototype.reverse->>reverse_array_spec_path: reverse exotic array
  reverse_array_spec_path->>Array indexed properties: check presence and read values
  reverse_array_spec_path->>Array indexed properties: set or delete paired indices

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Possibly related PRs

• PerryTS/perry#8400: Covers the same exotic-index reverse and array mutation fixes.
• PerryTS/perry#8366: Applies similar spec-compliant exotic-array mutation handling to pop.
• PerryTS/perry#8397: Relates to GC rekeying of array side-table ownership covered by the regression test.

Suggested reviewers: jdalton, thehypnoo

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/8400-array-reverse-exotic-rebased

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