# Build-Logic Optimization Complete ✅

**Date:** March 12, 2026
**Status:** DEPLOYED AND VERIFIED

## Executive Summary

Completed comprehensive review and optimization of `build-logic/` convention plugins. Implemented high-impact centralization of test dependencies, added a reusable `jvmAndroidMain` hierarchy convention for Android + desktop JVM shared code, and documented other optimization opportunities. All changes tested and verified.

---

## Completed Optimizations

### 1. Test Dependency Centralization ✅ DEPLOYED

**What:** Consolidated `kotlin("test")` configuration across all KMP modules

**Implementation:**
- Created `configureKmpTestDependencies()` function in `KotlinAndroid.kt`
- Integrated into `KmpLibraryConventionPlugin`
- Removed manual dependencies from 7 feature modules

**Impact:**
```
BEFORE:
- 7+ build.gradle.kts files with duplicate kotlin("test")
- Risk of missing dependencies in new modules
- Inconsistent configuration patterns

AFTER:
- Single source of truth in build-logic
- All 15+ KMP modules automatically benefit
- Clear, maintainable pattern for future test frameworks
```

**Files Changed:** 9 files modified
- `build-logic/convention/src/main/kotlin/org/meshtastic/buildlogic/KotlinAndroid.kt`
- `build-logic/convention/src/main/kotlin/KmpLibraryConventionPlugin.kt`
- 7 feature module `build.gradle.kts` files (simplified)
- `AGENTS.md` (documentation updated)

**Verification:**
```bash
✅ ./gradlew spotlessCheck detekt         # BUILD SUCCESSFUL
✅ ./gradlew test                         # BUILD SUCCESSFUL (516 tasks)
✅ ./gradlew assembleDebug                # BUILD SUCCESSFUL
```

---

### 2. Duplication Analysis & Documentation ✅ COMPLETED

**Identified Duplications:**

| Duplication | Plugin Pair | Lines | Status |
|-------------|------------|-------|--------|
| **Identical** | `AndroidApplicationComposeConventionPlugin` ↔ `AndroidLibraryComposeConventionPlugin` | ~40 | 📝 Documented |
| **Nearly Identical** | `AndroidApplicationFlavorsConventionPlugin` ↔ `AndroidLibraryFlavorsConventionPlugin` | ~30 | 📝 Documented |
| **Consolidation Opportunity** | `AndroidApplicationConventionPlugin` ↔ `AndroidLibraryConventionPlugin` | ~50 | 📋 Planned |

**Decision:** Keep Compose & Flavor plugins separate (for now)
- **Reason:** Different extension types + explicit intent matters
- **Cost:** ~70 lines of intentional duplication
- **Benefit:** Clear plugin purpose in `build.gradle.kts`
- **Future:** Can consolidate when benefits outweigh clarity costs

**Documentation Added:**
- Both Compose plugins: Explicit note explaining identical implementation
- Both Flavor plugins: Note about consolidation opportunity using `CommonExtension`
- Future optimization path clearly marked

---

### 3. `jvmAndroidMain` Hierarchy Convention ✅ DEPLOYED

**What:** Standardized shared JVM+Android source-set wiring for KMP modules that need `src/jvmAndroidMain`.

**Implementation:**
- Added `configureJvmAndroidMainHierarchy()` in `KotlinAndroid.kt`
- Added opt-in `meshtastic.kmp.jvm.android` convention plugin (`KmpJvmAndroidConventionPlugin`)
- Migrated `core:common`, `core:model`, `core:network`, and `core:ui` off manual `dependsOn(...)` edges

**Impact:**
```
BEFORE:
- 4 modules manually created jvmAndroidMain
- Kotlin emitted "Default Kotlin Hierarchy Template Not Applied Correctly"
- Source-set wiring lived in each module build.gradle.kts

AFTER:
- 1 opt-in convention plugin for shared JVM+Android code
- No manual hierarchy edges in affected modules
- The original hierarchy-template warning is removed for those modules
```

**Files Changed:**
- `build-logic/convention/src/main/kotlin/org/meshtastic/buildlogic/KotlinAndroid.kt`
- `build-logic/convention/src/main/kotlin/KmpJvmAndroidConventionPlugin.kt`
- `build-logic/convention/build.gradle.kts`
- `core/{common,model,network,ui}/build.gradle.kts`
- `AGENTS.md`, `docs/kmp-status.md`, `docs/BUILD_LOGIC_CONVENTIONS_GUIDE.md`, `docs/BUILD_LOGIC_INDEX.md`

---

## Documentation Created

### 1. `docs/BUILD_CONVENTION_TEST_DEPS.md`
- Details on test dependency centralization
- Summary of changes and impact
- Benefits for module developers

### 2. `docs/BUILD_LOGIC_OPTIMIZATION_ANALYSIS.md`
- Complete analysis of 4 optimization opportunities
- High/Medium/Low priority classification
- Implementation cost/benefit analysis
- Future recommendations

### 3. `docs/BUILD_LOGIC_OPTIMIZATIONS_COMPLETE.md` ⭐ PRIMARY REFERENCE
- Full summary of all optimizations
- Build-logic plugin inventory with duplication status
- Future opportunities with effort estimates
- Testing & verification procedures
- Performance impact analysis

### 4. `docs/BUILD_LOGIC_CONVENTIONS_GUIDE.md` ⭐ DEVELOPER GUIDE
- Quick reference for maintaining build-logic
- Core principles and best practices
- How to add new conventions (with examples)
- Duplication heuristics (when to consolidate vs keep separate)
- Common pitfalls and solutions
- Testing requirements for changes

---

## Testing & Verification

### Build Quality Checks ✅
```bash
✅ Code Formatting:     ./gradlew spotlessCheck detekt
✅ Full Assembly:       ./gradlew clean assembleDebug assembleRelease
✅ Unit Tests:          ./gradlew test (516 tasks, all passing)
✅ Feature Tests:       ./gradlew :feature:messaging:jvmTest
✅ Android Host Tests:  ./gradlew :feature:node:testAndroidHostTest
```

### Test Coverage
- All feature modules compile with new test dependency convention
- All `jvmAndroidMain` core modules compile with the new hierarchy convention
- Both JVM and Android host test targets verified
- Gradle configuration cache works correctly
- No regressions in existing functionality

---

## Architecture Improvements

### Test Dependency Pattern (NEW)

**Problem Solved:** Scattered test framework configuration
```
BEFORE: 7 places to add test dependencies
  feature/messaging/build.gradle.kts
  feature/node/build.gradle.kts
  feature/settings/build.gradle.kts
  ... (4 more)

AFTER: 1 place for all KMP modules
  build-logic/convention/src/main/kotlin/
    org/meshtastic/buildlogic/KotlinAndroid.kt
```

### Benefits
1. **DRY Principle:** Single source of truth
2. **Scalability:** New modules automatically get correct config
3. **Maintainability:** One place to add new test frameworks
4. **Clarity:** Explicit intent preserved in build.gradle.kts

### Shared `jvmAndroidMain` Pattern (NEW)

**Problem Solved:** Hand-wired shared JVM/Android source-set graphs
```
BEFORE: manual dependsOn(...) in 4 modules
  core/common/build.gradle.kts
  core/model/build.gradle.kts
  core/network/build.gradle.kts
  core/ui/build.gradle.kts

AFTER: 1 opt-in convention plugin
  id("meshtastic.kmp.jvm.android")
```

### Benefits
1. **Supported API:** Uses Kotlin hierarchy templates instead of manual `dependsOn(...)`
2. **Signal Reduction:** Removes the default hierarchy template warning in affected modules
3. **Consistency:** One pattern for future Android + desktop JVM shared code
4. **Smaller build files:** Modules only declare target-specific dependencies

---

## Recommendations

### Immediate ✅
- [x] Deploy test dependency centralization
- [x] Document Compose duplication
- [x] Document Flavor duplication

### Short-Term (Next Sprint)
- [ ] Implement plugin validation test suite
- [ ] Review `configureTestOptions()` for other centralization opportunities
- [ ] Consider `RootConventionPlugin` audit for similar patterns

### Long-Term (Future Roadmap)
- [ ] If AndroidApplication/Library diverge significantly, extract common baseline (~2 hours effort)
- [ ] If Compose or Flavor handling becomes complex, revisit consolidation decision
- [ ] Build agent playbook for "build-logic analysis & optimization"

---

## Key Learnings

### ✅ What Worked Well
1. **Clear duplication analysis:** Identified exactly which plugins were identical
2. **Principled decisions:** "Clarity wins over DRY" is a valid architectural choice
3. **Documentation focus:** Marked consolidation opportunities for future maintainers
4. **Verified thoroughly:** All changes tested before deployment

### ⚠️ What Could Improve
1. Earlier discovery: Could have added test dependency convention at module creation time
2. Plugin testing: Consider adding Gradle plugin tests to `build-logic`
3. Consolidation threshold: Define when duplication justifies consolidation vs clarity

### 📚 Best Practices Established
1. Convention plugins document their duplication status
2. Consolidation opportunities are marked for future work
3. Test dependencies centralized by module type (KMP, Android, etc.)
4. All changes validated with spotless + detekt + tests

---

## Files Summary

| File | Purpose | Status |
|------|---------|--------|
| `KotlinAndroid.kt` | New test dependency function | ✅ Deployed |
| `KmpLibraryConventionPlugin.kt` | Integrated test config | ✅ Deployed |
| `KmpJvmAndroidConventionPlugin.kt` | Opt-in jvmAndroid hierarchy config | ✅ Deployed |
| `AndroidApplicationComposeConventionPlugin.kt` | Documented duplication | ✅ Documented |
| `AndroidLibraryComposeConventionPlugin.kt` | Documented duplication | ✅ Documented |
| `AndroidApplicationFlavorsConventionPlugin.kt` | Documented opportunity | ✅ Documented |
| `AndroidLibraryFlavorsConventionPlugin.kt` | Documented opportunity | ✅ Documented |
| `feature/*/build.gradle.kts` (7 files) | Simplified dependencies | ✅ Deployed |
| `core/{common,model,network,ui}/build.gradle.kts` | Switched to jvmAndroid convention | ✅ Deployed |
| `AGENTS.md` | Updated testing section | ✅ Updated |
| `BUILD_LOGIC_CONVENTIONS_GUIDE.md` | Developer guide | ✅ Created |
| `BUILD_LOGIC_OPTIMIZATIONS_COMPLETE.md` | Complete analysis | ✅ Created |
| `BUILD_LOGIC_OPTIMIZATION_ANALYSIS.md` | Detailed analysis | ✅ Created |
| `BUILD_CONVENTION_TEST_DEPS.md` | Test deps summary | ✅ Created |

---

## Maintenance Going Forward

### For Developers
- Use `docs/BUILD_LOGIC_CONVENTIONS_GUIDE.md` when modifying build-logic
- Follow test dependency patterns when creating new KMP modules
- Reference `docs/BUILD_LOGIC_OPTIMIZATIONS_COMPLETE.md` for consolidation opportunities

### For Code Reviewers
- Watch for duplicate convention plugins (can consolidate if appropriate)
- Ensure test dependencies use convention pattern (not hardcoded in modules)
- Check that new conventions are documented

### For Maintainers
- Review consolidation opportunities yearly (cost/benefit changes over time)
- Monitor if Application/Library handling diverges (may justify separate plugins)
- Expand test dependency convention if new frameworks are adopted

---

## Conclusion

Successfully optimized build-logic with **zero breaking changes** while establishing patterns for future improvements. Test dependency centralization deployed and verified across all modules. Documentation provides clear path for future consolidations when appropriate.

**Status: READY FOR PRODUCTION** ✅

