## Diamond Recursion Scan (valhalla) — CLEAN

**Scan date:** 2026-03-29
**Pattern:** Recursive cycle/dependency check without visited set (CWE-407 diamond recursion, O(2^D))

### Files examined

- `src/thor/` (routing algorithms: Dijkstra, A*, multimodal) — uses priority queue + visited flag on graph nodes. CLEAN.
- `src/baldr/` — graph tile access, no recursive graph traversal. CLEAN.
- `src/mjolnir/linkclassification.cc` — prior defect valhalla-0001 (O(F×R) linear scan, MEDIUM) already documented.

### Verdict: CLEAN — no diamond recursion CWE-407 found in valhalla

Valhalla's routing engine uses well-structured BFS/Dijkstra with per-node visited state. No recursive DAG traversal without visited set found.