fix(parser): harden Rust cfg(test) exclusion and remove file size cap

[tuannx]

Summary

Red-team review findings against the Rust parser in #18. Three fixes:

1. Comment between #[cfg(test)] and item broke test exclusion

Tree-sitter emits line_comment/block_comment as named children. A comment between the attribute and its item cleared pending_attributes before the mod_item was reached, so #[cfg(test)] mod tests was NOT skipped.

#[cfg(test)]
// unit tests for this module
mod tests { struct Fixture; }  // ← was leaking into graph

Fix: Skip comment nodes without clearing pending_attributes.

2. #[cfg(test)] on non-mod items was silently ignored

is_cfg_test was computed for ALL node types but only checked in the mod_item branch. Functions, structs, and impls annotated with #[cfg(test)] were extracted as production entities.

#[cfg(test)]
fn test_only_helper() {}  // ← was leaking into graph

#[cfg(test)]
struct TestFixture { x: u64 }  // ← was leaking into graph

Fix: Skip ALL items when is_cfg_test is true (early continue before the type dispatch).

3. Removed _MAX_FILE_BYTES (1MB) cap

• No other parser has a file size cap
• Silently drops real code (generated protobuf, diesel schemas often exceed 1MB)
• Never mitigated the recursion crashes it appeared to guard against
• The per-file except Exception boundary is the actual backstop

Regression tests

• test_rust_parser_skips_cfg_test_with_comment_between_attribute_and_item
• test_rust_parser_skips_cfg_test_on_non_mod_items
• test_rust_parser_handles_large_files_without_cap

Validation

• 21 Rust parser tests pass
• Ruff clean
• No behavioral change for production code (only test-annotated items are now correctly excluded)

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[github-actions]

Architecture Drift Report

Algorithm: PKG | Entities: 722 | Components: 7

Drift from Baseline

Metric	Baseline	Current	Delta
Components	7	7	+0
Similarity	—	0.98	—
BalancedArchitectureScore	—	0.68	—
PrincipleAlignmentScore	—	0.84	—
RCI	—	0.99	—
TurboMQ	—	0.24	—
BasicMQ	—	0.24	—
IntraConnectivity	—	0.00	—
InterConnectivity	—	0.01	—
TwoWayPairRatio	—	0.00	—
DependencyHealth	—	0.99	—
ComponentBalance	—	0.22	—
HubBalance	—	0.67	—
BoundaryClarity	—	1.00	—
DependencyDistribution	—	0.57	—
SmellDiscipline	—	0.91	—

Changes

• 52 entity movement(s) between components

Smells (1)

• Concern Overload: Tests

---

Generated by arcade-agent

[lemduc]

Merged into the reland, #39 (squash commit d2bb44b) — closing this one.

Everything real from this branch is in: the cfg(test)/comment hunk (a comment
between #[cfg(test)] and its item used to clear pending_attributes), the move
of the is_cfg_test check out of the mod_item branch so it applies to
functions, structs and impls too, and all three tests.

Two notes on the rest:

• The "remove file size cap" part was already a no-op — no cap existed at
  cbea67f, the base of this branch. The reland keeps Rust cap-free but says so
  honestly: parsers/go.py:20 and parsers/typescript.py:26 both define
  _MAX_FILE_BYTES = 1_000_000, so this is not a divergence from the other
  parsers, and it is only defensible because the reland also fixes an O(n²) in
  add_entity (5.2 MB generated file: 70.2 s → 3.0 s, identical entity and edge
  counts).
• Four more cfg(test) leak classes were still open after this branch —
  cfg(all(test, …))/cfg(any(test, …)), inner #![cfg(test)], out-of-line
  #[cfg(test)] mod x;, and #[cfg(test)] use … — and are fixed in feat(parser): add Rust support (roadmap #16b) — reland of #18 + #29 #39 with a
  test each. A probe crate with 2 production structs and 10 test-only entities
  went from 10 entities (8 leaked) to exactly 2.

Thanks — the hardening work here carried over intact, with co-author credit on
every commit.