## Diamond Recursion Scan — CLEAN

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

### Files examined

- `src/Composer/DependencyResolver/Solver.php` — SAT solver core
- `src/Composer/DependencyResolver/PoolBuilder.php` — dependency pool construction
- `src/Composer/DependencyResolver/PoolOptimizer.php` — pool optimization
- `src/Composer/DependencyResolver/Request.php` — dependency request types
- `src/Composer/Package/` — package dependency structures

### Findings

**Solver:** Uses a DPLL-based SAT solver (via branch/backtrack state machine in `$this->branches`). Does not use recursive graph traversal for dependency resolution. No diamond recursion possible. CLEAN.

**PoolBuilder:** Iterates dependency sets iteratively (while loops), not recursively. CLEAN.

**Package layer:** Dependencies are stored as flat arrays; traversal is left to the solver. No recursive diamond-pattern code found. CLEAN.

Note: `composer-0001` and `composer-0002` cover pre-existing CWE-407 defects in filter/dependent list operations.

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