## 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.