## Diamond Recursion Scan (tensorflow) — CLEAN (deeper scan)

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

### Files examined

- `tensorflow/python/ops/variables.py:_has_cycle` — uses `state` dict with _STARTED/_FINISHED markers (three-color DFS) — CLEAN
- `tensorflow/python/keras/engine/functional.py:_build_map_helper` — uses `finished_nodes` set + `nodes_in_progress` set — CLEAN
- `tensorflow/python/checkpoint/restore.py` — uses BFS with deferred queue — CLEAN
- `tensorflow/python/ops/control_flow_util_v2.py:resource_input_index` — linear parent-chain walk, not DAG traversal — CLEAN

### Verdict: CLEAN — no diamond recursion CWE-407 found beyond existing tensorflow-0001