# Beads Coverage Analysis: GIL Release Implementation Plan

**Date:** January 5, 2026  
**Status:** Phase C Complete – Phase H Ready to Start  
**Purpose:** Verify beads tracking covers the entire GIL Release Hybrid Implementation Plan

---

## Executive Summary

**Finding:** Beads tracks **Phases C and H comprehensively**, but **Phases D, E, F, G are tracked via legacy epic (mrrc-9wi) without clear linkage to C/H completion gates**.

**Recommendation:** Update beads structure to explicitly link Phase H.Gate → Phase E/F/G, clarifying that Phases E-G depend on H.Gate completion (not just H existence).

---

## 1. Coverage by Phase

### Phase A: Core Buffering
- **Plan Status:** ✅ Complete (Jan 1-2)
- **Beads Status:** Not explicitly tracked (pre-beads work)
- **Assessment:** ✓ No action needed

### Phase B: GIL Integration
- **Plan Status:** ✅ Complete (code done, issues resolved)
- **Beads Status:** Tracked in legacy issues (mrrc-gyk, mrrc-18s, etc.)
- **Assessment:** ✓ Complete and documented in mrrc-hjx closure

### Phase C: Batch Reading (Compatibility Path)
- **Plan Status:** ✅ Complete (Jan 3-5, 2026)
- **Beads Status:** Tracked as epic mrrc-ppp
  - mrrc-ppp (Epic)
  - mrrc-ppp.0-ppp.4 (C.0-C.2, closed)
  - mrrc-ppp.5 (C.3, closed)
  - mrrc-ppp.6 (C.4, closed)
  - mrrc-ppp.7 (C.Gate, closed)
- **Assessment:** ✓ Fully tracked and completed

### Phase H: Pure Rust I/O + Rayon
- **Plan Status:** 🚀 Ready to start (next critical path)
- **Beads Status:** Tracked as epic mrrc-7vu with 10 subtasks
  - mrrc-7vu.3 (H.0: Rayon PoC)
  - mrrc-7vu.4 (H.1: Type Detection)
  - mrrc-7vu.5 (H.2: RustFile)
  - mrrc-7vu.6 (H.2b: CursorBackend)
  - mrrc-7vu.7 (H.3: Sequential Baseline)
  - mrrc-7vu.8 (H.4a: Record Boundary Scanner)
  - mrrc-7vu.9 (H.4b: Rayon Parser Pool)
  - mrrc-7vu.10 (H.4c: Producer-Consumer)
  - mrrc-7vu.11 (H.5: Integration Tests)
  - mrrc-7vu.12 (H.Gate: Benchmarking)
- **Assessment:** ✓ Fully tracked and structured

### Phase D: Writer Implementation Update
- **Plan Status:** ⚠️ Deferred (Writer secondary to reading)
- **Beads Status:** **Not explicitly tracked under mrrc-ppp or mrrc-7vu**
- **Plan Reference:** GIL_RELEASE_HYBRID_IMPLEMENTATION_PLAN.md §6 defers this
- **Assessment:** ⚠️ **Missing explicit beads representation**
  - Should either: (a) create Phase D epic linked to C/H, or (b) document deferral in notes

### Phase E: Comprehensive Validation & Testing
- **Plan Status:** ⏸️ Blocked on H.Gate completion
- **Beads Status:** Tracked as mrrc-9wi.4 (Epic) with 2 subtasks
  - mrrc-9wi.4.1 (Concurrency testing)
  - mrrc-9wi.4.2 (Regression testing)
- **Plan Coverage:**
  - E.1: Thread Safety Verification (mrrc-9wi.4.1 ✓)
  - **Missing in beads:** Race condition torture tests from mrrc-kzw (not linked to E.1)
- **Assessment:** ⚠️ **Partially tracked; mrrc-kzw (race conditions) should be sub-task of E.1**

### Phase F: Benchmarking & Performance Analysis
- **Plan Status:** ⏸️ Blocked on H.Gate completion
- **Beads Status:** Tracked as mrrc-9wi.5 (Epic) with 2 subtasks
  - mrrc-9wi.5.1 (Measure threading speedup curve)
  - mrrc-9wi.5.2 (Compare to pure Rust baseline)
- **Plan Coverage:**
  - F.1: Comparative Benchmark Suite (compares pymarc, pymrrc legacy, batching, pure Rust)
  - **Beads only shows post-H measurements, not comparative structure**
- **Assessment:** ⚠️ **Tracked, but scope is narrower than plan; missing pymarc/legacy comparisons**

### Phase G: Documentation Refresh
- **Plan Status:** ⏸️ Blocked on H.Gate completion
- **Beads Status:** Tracked as mrrc-9wi.6 (Epic) with 4 subtasks
  - mrrc-9wi.6.1 (Update README & API docs)
  - mrrc-9wi.6.2 (Create PERFORMANCE.md)
  - mrrc-9wi.6.3 (Update ARCHITECTURE.md & CHANGELOG)
  - mrrc-9wi.6.4 (Create example code)
- **Plan Coverage:** GIL_RELEASE_HYBRID_IMPLEMENTATION_PLAN.md doesn't specify Phase G details
- **Assessment:** ✓ Tracked and detailed in mrrc-9wi.6

---

## 2. Dependency Chain Coverage

**Plan's Critical Path:**
```
Phase C (C.Gate) → Phase H.3 (sequential baseline) → Phase H.4 (parallelism) → Phase H.Gate
                                                                                    ↓
                                                  Phase E (validation) + Phase F (benchmarking)
                                                                                    ↓
                                                        Phase G (documentation)
```

**Beads Representation:**

| Dependency | Plan | Beads | Status |
|-----------|------|-------|--------|
| C → H.3 | Explicit | H.3 notes mention C.Gate | ✓ Documented in task descriptions |
| H.Gate → E | Implicit in plan §7 | **Missing explicit dependency** | ⚠️ E/F/G marked open but should be blocked |
| H.Gate → F | Implicit in plan §7 | **Missing explicit dependency** | ⚠️ Same as above |
| H.Gate → G | Implicit in plan §7 | **Missing explicit dependency** | ⚠️ Same as above |

**Key Issue:** Beads shows E/F/G as `open` with no blocking relationship to H.Gate. Plan intends them to be blocked until H.Gate passes.

---

## 3. Coverage Gaps

### Critical Gaps (Block Execution)
None. Phases C and H are fully tracked with clear task breakdown.

### Important Gaps (Clarity Issues)

1. **Phase D Status Ambiguous**
   - Plan §6 explicitly defers Phase D (Writer backend refactoring)
   - Beads has no Phase D epic or explicit deferral marker
   - **Action:** Create issue mrrc-d00 (Phase D: Writer Backend—Deferred) with note: "Deferred per GIL_RELEASE_HYBRID_IMPLEMENTATION_PLAN.md §6; Writer less critical for read-analyze use case. Revisit after Phase H.Gate."

2. **Phase E/F/G Blocking Relationships Missing**
   - Beads shows `mrrc-9wi.4`, `mrrc-9wi.5`, `mrrc-9wi.6` as `open`, independent of H.Gate
   - Plan intends these to be blocked by H.Gate
   - **Action:** Update beads with explicit dependency: `--deps blocked-by:mrrc-7vu.12` for each of E, F, G epics

3. **Race Condition Tests (mrrc-kzw) Not Linked to E.1**
   - mrrc-kzw exists as standalone issue
   - Plan §7 E.1 references "race condition torture tests (from `mrrc-kzw`)"
   - Beads doesn't show mrrc-kzw as sub-task of mrrc-9wi.4.1
   - **Action:** Link mrrc-kzw to E.1 task via note or parent relationship

4. **Benchmark Fixture Generation Task Missing**
   - Plan §7.2 specifies 4 fixture sizes (1k, 10k, 100k, pathological)
   - No dedicated beads task for generating these
   - **Action:** Create mrrc-f00 (Phase F: Benchmark Fixtures & Setup) as subtask of F

5. **Diagnostic Infrastructure Task Underspecified**
   - mrrc-can (Infrastructure: Diagnostic Test Suite) exists
   - Plan §7.1 specifies 3 diagnostic utilities: GIL release verification, batch size profiling, Python file overhead
   - Beads doesn't show these 3 as sub-tasks
   - **Action:** Break mrrc-can into 3 sub-tasks:
     - C.Diag.1: GIL Release Verification Test
     - C.Diag.2: Batch Size Benchmarking Script
     - C.Diag.3: Python File I/O Overhead Profiler

6. **ASAN/Valgrind CI Integration Not Tracked**
   - Plan §7 mentions "ASAN/Valgrind CI integration"
   - No beads task for this
   - **Action:** Consider adding low-priority task or including in E.1 (Concurrency Testing)

---

## 4. Explicit Unknowns in Beads

### Issues Without Clear Derivation from Plan

| Beads ID | Title | Plan Reference | Assessment |
|----------|-------|-----------------|------------|
| mrrc-53g | Debug Phase 2 closure behavior | Not in plan | ℹ️ Diagnostic issue from GIL investigation |
| mrrc-u0e | Performance profiling | Not in plan | ℹ️ Diagnostic issue from GIL investigation |
| mrrc-br3 | Retest Phase B with diagnostic fixes | Not in plan | ℹ️ Follow-up from Phase B troubleshooting |
| mrrc-kzw | Thread safety tests & concurrency validation | Plan §7 E.1 | ✓ Intended for Phase E |
| mrrc-18s | Implement BufferedMarcReader with SmallVec | Plan §3.1 | ✓ Implemented in Phase C |
| mrrc-4rm | Document GIL Release findings | Plan §7 | ✓ Diagnostic documentation |
| mrrc-5ph | Optimize batch reading (Phase C) | Plan §3 | ✓ Covered by mrrc-ppp |
| mrrc-pfw | Phase C Deferral Gate | Plan §3.2 decision tree | ✓ Gate logic captured |

---

## 5. What's NOT in Beads But Should Be

Based on plan sections not explicitly tracked:

### Diagnostic Infrastructure (Phase C & H)
```
bd create "C.Diag.1: GIL Release Verification Test (concurrent reader)" \
  -t task -p 1 --parent mrrc-can
bd create "C.Diag.2: Batch Size Benchmarking Script (10-500 sweep)" \
  -t task -p 1 --parent mrrc-can
bd create "C.Diag.3: Python File I/O Overhead Profiler" \
  -t task -p 1 --parent mrrc-can
```

### Benchmark Fixtures (Phase F)
```
bd create "F.Setup: Benchmark Fixture Generation (1k, 10k, 100k, pathological)" \
  -t task -p 2 --parent mrrc-9wi.5
```

### Phase D: Writer Deferral
```
bd create "Phase D: Writer Backend Refactoring (Deferred)" \
  -t epic -p 4 --json
# Note: "Deferred per GIL plan §6; revisit after Phase H.Gate"
```

### Phase E/F/G Blocking
```
bd update mrrc-9wi.4 --deps blocked-by:mrrc-7vu.12
bd update mrrc-9wi.5 --deps blocked-by:mrrc-7vu.12
bd update mrrc-9wi.6 --deps blocked-by:mrrc-7vu.12
```

---

## 6. Verification Checklist

### What's Covered ✓
- [x] Phase C epic with all 7 subtasks (C.0-C.Gate)
- [x] Phase H epic with all 10 subtasks (H.0-H.Gate)
- [x] C.Gate → H.3 dependency documented in task descriptions
- [x] All task titles match plan nomenclature (C.0-C.Gate, H.0-H.Gate)
- [x] Infrastructure diagnostic task exists (mrrc-can)

### What's Missing ⚠️
- [ ] Explicit mrrc-ppp.7 (C.Gate) → mrrc-7vu.7 (H.3) dependency link in beads
- [ ] Phase D (Writer) epic or explicit deferral marker
- [ ] H.Gate → E/F/G blocking dependencies
- [ ] Diagnostic sub-tasks under mrrc-can (3 utilities specified in plan §7.1)
- [ ] Benchmark fixture generation task (plan §7.2)
- [ ] ASAN/Valgrind CI integration task
- [ ] mrrc-kzw linked to E.1 (Concurrency Testing)

### Optional Improvements
- [ ] Create/update quick reference query for Phase H status (currently only Phase C exists)
- [ ] Document risk register from plan §9 in a beads issue (optional; informational)

---

## 7. Recommendations

### Priority 1: Enable Correct Dependency Tracking
1. **Add explicit C.Gate → H.3 dependency** (if not already encoded in descriptions)
2. **Add H.Gate → E/F/G blocking dependencies** (critical for preventing premature start)

### Priority 2: Fill Documentation Gaps
1. **Create Phase D epic** with explicit deferral note
2. **Create diagnostic sub-tasks** under mrrc-can (3 utilities from plan §7.1)
3. **Link mrrc-kzw to E.1** explicitly

### Priority 3: Enhance Tracking
1. **Create benchmark fixture task** under Phase F
2. **Consider ASAN CI integration task** (low priority, can be documentation-only)

### Priority 4: Documentation
1. **Update BEADS_COVERAGE_ANALYSIS.md** (this document) to live in repo
2. **Update README_BEADS_INTEGRATION.md** to reference this analysis
3. **Document Phase D deferral** in session handoff

---

## 8. Action Items for Next Session

After Phase H.0 starts, revisit this analysis:
- [ ] Verify no new issues were created outside Phase H epic
- [ ] Confirm E/F/G remain blocked until H.Gate passes
- [ ] Track diagnostic sub-task completions under mrrc-can
- [ ] Update this document with actual timeline vs. estimated timeline (for project retrospective)

---

## Conclusion

**Beads substantially reflects the GIL Release plan** with full coverage of Phases C and H (critical path). **Minor gaps exist in:
1. Explicit dependency links (C.Gate → H.3 → E/F/G)
2. Phase D deferral documentation
3. Diagnostic infrastructure decomposition

These gaps do **not block execution** but reduce clarity. Recommended fixes are simple beads updates that take <15 minutes total.

**Overall Assessment:** ✓ **Ready to proceed with Phase H** – beads structure is sufficient for execution.

---

**Document Date:** January 5, 2026  
**Prepared for:** Next session planning and Phase H kickoff
