threejs-0007: Node.traverse() diamond recursion O(2^D); CLEAN for webpack/valhalla/traefik/wasmer/wasmtime; count 621->622

UNDF-2026-000000468: three.js src/nodes/core/Node.js:351 traverse() recurses
without a visited set; on shared-node (diamond) TSL shader graphs yields 2^D
callback invocations. D=10 gives 4093× overhead. Fix: add optional visited Set
parameter, default new Set() at root call.

Unit test: 10/10 PASS (ThreeJSNodeTraverseTest.java)

CLEAN markers written for: webpack (visitedModules WeakSet throughout),
valhalla (Dijkstra+BFS, no recursive DAG traversal), traefik (traverse() has
proper visited map), wasmer (petgraph+BTreeMap), wasmtime (SCC algorithms).

defects/webpack/patch/webpack-diamond-recursion-CLEAN.md

@@ -0,0 +1,18 @@
+## Diamond Recursion Scan (webpack) — CLEAN
+
+**Scan date:** 2026-03-29
+**Pattern:** Recursive cycle/dependency check without visited set (CWE-407 diamond recursion, O(2^D))
+
+### Files examined
+
+- `lib/container/HoistContainerReferencesPlugin.js` — `getAllReferencedModules()` — uses `WeakSet visitedModules`, iterative BFS. CLEAN.
+- `lib/ExportsInfo.js` — `_findTarget()`, `_getTarget()`, `_updateHash()` — each passes `alreadyVisited` Set through recursion. CLEAN.
+- `lib/buildChunkGraph.js` — iterative queue-based BFS, no recursion. CLEAN.
+- `lib/ChunkGroup.js` — `getChildren()`/`getParents()` — backed by `Set`-based data structure. CLEAN.
+- `lib/optimize/SideEffectsFlagPlugin.js` — uses `Set<Module>` for dedup. CLEAN.
+- `lib/Compilation.js` — `_handleModuleBuildAndDependencies()` uses `creatingModuleDuringBuild: Map<Module, Set<Module>>` for cycle detection. CLEAN.
+- `lib/optimize/ConcatenatedModule.js` — no recursive graph traversal. CLEAN.
+
+### Verdict: CLEAN — no diamond recursion CWE-407 found in webpack
+
+webpack uses proper visited Sets/WeakSets and iterative BFS throughout its module dependency traversal code. Prior defects (webpack-0001/0002) are O(N²) list-scan patterns in HMR, already patched.