fix(compile): omit erased names from module namespaces

[proggeramlug]

Summary

• derive module namespace keys from consumer-visible export names so private backing functions such as _null do not leak beside their public aliases
• exclude erased TypeScript interfaces and type aliases when materializing dynamic and nested namespace objects
• add a Zod-shaped regression for import * as z; export { z }, nested export * as coerce, reflection, alias-only exports, and type erasure

Verification

On root@perrymaster.skelpo.net:

• cargo fmt --all -- --check
• cargo build --release -p perry
• cargo build --release -p perry-runtime-static -p perry-stdlib-static
• ./run_parity_tests.sh --filter namespace_type_erasure_8904
• ./run_parity_tests.sh --filter export_star_as_namespace_object
• ./run_parity_tests.sh --filter namespace_import_enumerable
• real Zod 4.3.5 no-cache compile: Object.keys(z).length === 236 in both Node and Perry, z.coerce is owned/enumerable, and z.coerce.number()("42") === 42

No version bump.

Fixes #8904

Summary by CodeRabbit

• Bug Fixes

  • Fixed namespace exports so type-only declarations are excluded from runtime namespace objects.
  • Prevented private backing names from appearing as public exports.
  • Ensured nested and dynamically imported namespaces expose only valid runtime values.

• Tests

  • Added coverage for namespace re-exports, enumerable properties, runtime keys, and numeric coercion behavior.

[coderabbitai]

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Reviewing files that changed from the base of the PR and between 9c7d1fc and b9afb22.

📒 Files selected for processing (1)

• changelog.d/8994-namespace-erased-names.md

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Configuration used: defaults

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Run ID: fcb4214b-bae0-4e7a-8b83-f1d4ad487ea1

📥 Commits

Reviewing files that changed from the base of the PR and between 4b9dde9 and 9c7d1fc.

📒 Files selected for processing (5)

• crates/perry/src/commands/compile/run_pipeline.rs
• test-files/issue_8904_namespace_materialization/coerce.ts
• test-files/issue_8904_namespace_materialization/external.ts
• test-files/issue_8904_namespace_materialization/index.ts
• test-files/test_gap_namespace_type_erasure_8904.ts

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📝 Walkthrough

Walkthrough

The compiler now excludes type-only declarations and private backing names from runtime exports and namespace entries. New regression fixtures verify aliased values, nested namespaces, enumerable properties, and erased declarations.

Changes

Namespace type erasure

Layer / File(s)	Summary
Runtime export filtering crates/perry/src/commands/compile/run_pipeline.rs	Adds type-only binding detection. Runtime export population now uses public export names and skips erased declarations.
Namespace entry filtering crates/perry/src/commands/compile/run_pipeline.rs	Dynamic-import and nested-namespace entries now omit type-only bindings.
Namespace regression coverage test-files/issue_8904_namespace_materialization/*, test-files/test_gap_namespace_type_erasure_8904.ts	Adds aliased runtime values, erased declarations, a nested namespace, and checks for the expected runtime namespace shape.

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

Merge Risk: ⚪ Minimal · up to 9c7d1

Compiled module namespaces will omit private backing names and erased TypeScript declarations while preserving runtime exports and aliases. No actionable merge-blocking risk remains beyond normal checks and review.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 40.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 5 functions across 5 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
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.
Title check	✅ Passed	The title clearly and concisely describes the main change: excluding erased names from module namespace objects.
Description check	✅ Passed	The description explains the changes, identifies issue #8904, lists verification commands and results, and confirms no version bump. It uses a "Verification" heading instead of "Test plan" and omits t…

Full details: Description check

Explanation

The description explains the changes, identifies issue #8904, lists verification commands and results, and confirms no version bump. It uses a "Verification" heading instead of "Test plan" and omits the checklist, but it is otherwise complete and relevant.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[proggeramlug]

Merged, validated as a batch of six on current main.

Validation — runtime 2786/0, parser 40/0, codegen 1341/0 (RUST_TEST_THREADS=1); scripts/run_lint_gates.sh 57 of 58 including the compile tier (cargo check --workspace --all-targets under -D warnings, and clippy) — the exception is the pre-existing Actions-expression artifact (#8929). All six stacked without conflict.

One fix pushed: this PR touches crates/ with no changelog fragment and no skip-changelog label, so the changeset gate in lint would have rejected it. Added one. Four of the six PRs in this batch had the same gap.