fix(runtime): materialize error stacks during inspect

[proggeramlug]

util.inspect(new Error("outer", { cause })) and AggregateError inspection lost their stack/body layout after Error stacks became lazy in #9486. The formatter read ErrorHeader.stack directly, saw the pre-materialization null slot, and emitted the property body on a standalone { line; the node-suite/util/inspect/error-cause-and-aggregate parity row consequently failed.

Route inspection through the shared lazy stack materializer before selecting the displayed frame. This preserves captured frames until inspection actually consumes them and restores Node-compatible formatting for Error causes and AggregateError entries.

Tracked by #9202.

Validation:

• ./run_parity_tests.sh --suite node-suite --module util --filter error-cause-and-aggregate (1/1)
• ./run_parity_tests.sh --suite node-suite --module util (88/88)
• cargo test --profile perry-dev -p perry-runtime -- --test-threads=1 (3,256 passed, 4 ignored; doc tests 8 ignored)
• ./scripts/run_lint_gates.sh (all 64 local gates passed; 2 CI-only expressions skipped)

Summary by CodeRabbit

• Bug Fixes
  • Fixed error inspection so lazily generated stack traces are materialized correctly.
  • Improved formatting for errors with causes and aggregate errors, preserving the expected stack and body layout.

[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: 699c0f64-c061-4036-8ad3-984442c08ea3

📥 Commits

Reviewing files that changed from the base of the PR and between 87dc334 and dd4a1a1.

📒 Files selected for processing (2)

• changelog.d/9933-util-inspect-lazy-error-stack.md
• crates/perry-runtime/src/builtins/formatting/errors.rs

Included review availability: Your plan provides up to 8 included reviews per hour; 5 remain after this review.

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📝 Walkthrough

Walkthrough

util.inspect() now materializes lazy Error stacks before formatting Errors with a cause or AggregateError with errors. The changelog documents the Node-compatible stack and body layout fix.

Changes

Lazy Error inspection

Layer / File(s)	Summary
Stack materialization during formatting crates/perry-runtime/src/builtins/formatting/errors.rs, changelog.d/9933-util-inspect-lazy-error-stack.md	format_error_stack_frame materializes the Error stack before reading it. The changelog records the fix for cause and AggregateError formatting.

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

Merge Risk: ⚪ Minimal · up to dd4a1

Error inspection now preserves lazy stack frames when displaying causes and AggregateError entries, restoring expected stack and body formatting. No current merge-blocking risk remains.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 2 functions across 1 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 main runtime change: materializing lazy error stacks during inspection.
Description check	✅ Passed	The description explains the issue, implementation, tracked issue, and validation results. It does not reproduce every template heading, but it provides the required substantive information.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

Full details: Docstring Coverage

Explanation

Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 2 functions across 1 files. (1 skipped: 1 unsupported.)

• Fix all pre-merge checks with AI

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[proggeramlug]

Landed on main via merge train #9939. Validated as a tree: 66/66 lint gates, and perry-runtime/codegen/hir/stdlib all green (5,966 tests, 0 failures). Thanks!