Forward-looking priorities for the Meshtastic KMP multi-target effort. For current state, see [`kmp-status.md`](./kmp-status.md). For the full gap analysis, see [`decisions/architecture-review-2026-03.md`](./decisions/architecture-review-2026-03.md).
## Architecture Health (Immediate)
These items address structural gaps identified in the March 2026 architecture review. They are prerequisites for safe multi-target expansion.
| Item | Impact | Effort | Status |
|---|---|---|---|
| Purge `java.util.Locale` from `commonMain` (3 files) | High | Low | ✅ |
| Replace `ConcurrentHashMap` in `commonMain` (3 files) | High | Low | ✅ |
| Create `core:testing` shared test fixtures | Medium | Low | ✅ |
| Add feature module `commonTest` (settings, node, messaging) | Medium | Medium | ✅ |
1.**Evaluate KMP-native testing tools** — ✅ **Done:** Fully evaluated and integrated `Mokkery`, `Turbine`, and `Kotest` across the KMP modules. `mockk` has been successfully replaced, enabling property-based and Flow testing in `commonTest` for iOS readiness.
2.**Desktop Map Integration** — Address the major Desktop feature gap by implementing a raster map view using [**MapComposeMP**](https://github.com/p-lr/MapComposeMP).
- Implement a `MapComposeProvider` for Desktop.
- Implement a **Web Mercator Projection** helper in `feature:map/commonMain` to translate GPS coordinates to the 2D image plane.
- Leverage the existing `BaseMapViewModel` contract.
3.**Unify `MapViewModel`** — Collapse the remaining Google and F-Droid specific `MapViewModel` classes in the `:app` module into a single `commonMain` implementation by isolating platform-specific settings (styles, tile sources) behind a repository interface.
2.**`core:api` contract split** — separate transport-neutral service contracts from the Android AIDL packaging to support iOS/Desktop service layers.
3.**Decouple Firmware DFU** — `feature:firmware` relies on Android-only DFU libraries. Evaluate wrapping this in a shared KMP interface or extracting it to allow the core `feature:firmware` module to be utilized on desktop/iOS.
- **iOS Maps & Camera:** Implement `MapLibre` or `MKMapView` via Compose Multiplatform's `UIKitView`. Leverage `AVCaptureSession` wrapped in `UIKitView` to fulfill the `LocalBarcodeScannerProvider` contract.
- **Web (wasmJs) Integrations:** Leverage `HtmlView` to embed raw DOM elements (e.g., `<video>`, `<iframe>`, or canvas-based maps) directly into the Compose UI tree while binding the root app via `CanvasBasedWindow`.
2.**Module maturity dashboard** — living inventory of per-module KMP readiness.
3.**Shared UI vs Shared Logic split** — If the iOS target utilizes native SwiftUI instead of Compose Multiplatform, evaluate splitting feature modules into pure `sharedLogic` (business rules, ViewModels) and `sharedUI` (Compose Multiplatform) to prevent dragging Compose dependencies into pure native iOS apps.
2.**Interfaces in `commonMain`, implementations per-target.** The repository pattern is established — extend it. Prefer dependency injection (Koin) with interfaces over `expect`/`actual` declarations whenever possible to keep architecture decoupled and highly testable.
3.**UI Interop Strategies.** When a Compose Multiplatform equivalent doesn't exist (e.g., Maps, Camera), use standard interop APIs rather than extracting the entire screen to native code. Use `AndroidView` for Android, `UIKitView` for iOS, `SwingPanel` for JVM/Desktop, and `HtmlView` for Web (`wasmJs`). Always wrap these in a shared `commonMain` interface contract (like `LocalBarcodeScannerProvider`).
4.**Stubs are a valid first implementation.** Every target starts with no-op stubs, then graduates to real implementations.
5.**Feature modules stay target-agnostic in `commonMain`.** Platform UI goes in platform source sets. Keep the UI layer dumb and rely on shared ViewModels (Unidirectional Data Flow) to drive state.
6.**Transport is a pluggable adapter.** BLE, serial, TCP, MQTT all implement `RadioTransport` and are orchestrated by a shared `RadioInterfaceService`.
7.**CI validates every target.** If a module declares `jvm()`, CI compiles it. No exceptions. Run tests on appropriate host runners (macOS for iOS, Linux for JVM/Android) to catch platform regressions.
8.**Test in `commonTest` first.** ViewModel and business logic tests belong in `commonTest` so every target runs them. Use shared `core:testing` utilities to minimize duplication.
9.**Zero Platform Leaks.** Never import `java.*` or `android.*` inside `commonMain`. Use KMP-native alternatives like `kotlinx-datetime` and `Okio`.