Meshtastic-Android/.github/copilot-instructions.md

Meshtastic Android — Copilot Instructions

Build, Test & Lint

Requires: JDK 21, ANDROID_HOME set, proto submodule initialized.

# Bootstrap (run once per fresh clone)
git submodule update --init
[ -f local.properties ] || cp secrets.defaults.properties local.properties

# Full local verification (formatting → lint → compile → tests)
./gradlew spotlessApply detekt assembleDebug test allTests

# Single module tests (KMP module)
./gradlew :core:data:allTests

# Single module tests (Android-only module like :app)
./gradlew :app:testFdroidDebugUnitTest

# Cross-platform compilation check (no tests)
./gradlew kmpSmokeCompile

# Flavor-specific lint
./gradlew lintFdroidDebug lintGoogleDebug

Both test AND allTests are needed. allTests covers KMP modules; test covers pure-Android modules. Neither alone catches everything.

Gradle task naming (KMP vs Android-only)

KMP modules have different task names than pure-Android modules. Using the wrong name silently skips tests or fails resolution.

Intent	KMP modules (core:*, feature:*)	Android-only (app, core:api, core:barcode)
Run tests	:module:allTests	:module:testFdroidDebugUnitTest
Detekt	:module:detekt (lifecycle task)	:module:detekt
Compile check	:module:compileKotlinJvm	:module:compileFdroidDebugKotlin

Common mistakes:

• ❌ :core:network:detektMain — does not exist in KMP; variants are detektJvmMain, detektMetadataCommonMain, etc. Use :core:network:detekt instead.
• ❌ :feature:connections:testDebugUnitTest — ambiguous in KMP modules. Use :feature:connections:allTests.
• ❌ :feature:connections:compileFdroidDebugKotlin — wrong for KMP. Use :feature:connections:compileKotlinJvm or kmpSmokeCompile.

Architecture

Kotlin Multiplatform project targeting Android, Desktop (JVM), and iOS. Business logic lives in commonMain; platform shells (app/, desktop/) wire DI and host UI.

Module layers

Layer	Modules	Role
Host	app, desktop	Platform shell, Koin root, theme
Feature	feature/*	Self-contained screens (KMP, meshtastic.kmp.feature plugin)
Core	core/*	Shared logic, data, networking, UI components

Key technologies

• UI: Compose Multiplatform + Material 3 Adaptive
• Navigation: JetBrains Navigation 3 (@Serializable sealed interface routes in core:navigation)
• DI: Koin 4.2+ with K2 Compiler Plugin (@Module, @KoinViewModel, startKoin<AndroidKoinApp>)
• Networking: Ktor (no OkHttp)
• BLE: Kable (via core:ble)
• Database: Room KMP
• I/O: Okio
• Build: Gradle Kotlin DSL with convention plugins in build-logic/
• Flavors: fdroid (OSS) / google (Maps + DataDog)

Navigation pattern

Feature navigation graphs are extension functions on EntryProviderScope<NavKey> in commonMain. The host shell renders via MeshtasticNavDisplay. Use NavigationBackHandler (not Android's BackHandler).

Key Conventions

Source-set boundaries

• commonMain — All business logic, ViewModels, UI. No java.* or android.* imports.
• androidMain — Android framework integration only. No business logic.
• jvmMain / jvmAndroidMain — Shared JVM code (Android + Desktop).
• Platform capabilities: prefer interface + DI over expect/actual.

Strings & formatting

• All strings in core/resources/src/commonMain/composeResources/values/strings.xml
• Use stringResource(Res.string.key) — never hardcoded strings.
• CMP only supports %N$s (string) and %N$d (int) — pre-format floats with NumberFormatter.format().
• Run python3 scripts/sort-strings.py after adding strings.

Error handling

• Use safeCatching {} (from core:common) instead of runCatching {} in suspend/coroutine code — runCatching swallows CancellationException.

Dispatchers

• Use org.meshtastic.core.common.util.ioDispatcher — never Dispatchers.IO directly.
• Inject CoroutineDispatchers from core:di.

Build-logic

• Convention plugins: meshtastic.kmp.feature, meshtastic.kmp.library, meshtastic.kmp.jvm.android, meshtastic.koin
• Use libs.library("alias-name") string-based lookups (not type-safe accessors) in convention plugins.
• Prefer lazy Gradle configuration (configureEach, withPlugin, provider APIs).

Icons

• Use MeshtasticIcons (from core/ui/icon/) instead of material.icons.Icons.

Protos

• core/proto/ is a read-only git submodule from meshtastic/protobufs. Never modify proto files.

Design standards

• All UI must conform to the Meshtastic Client Design Standards.
• Review new screens/significant UI changes against the standards before merge.

Branch naming

Branches must start with: bugfix/, enhancement/, dependencies/, or repo/.

Branching workflow

• origin = meshtastic/Meshtastic-Android (upstream, source of truth). Personal forks are typically behind.
• Always create branches off fetched upstream: git fetch origin && git checkout -b <name> origin/main
• Never branch from a personal fork's main — it may be stale.

Push workflow (verify-then-push)

Before push:

./gradlew spotlessApply detekt assembleDebug test allTests  # or targeted module tasks

Only push when the above passes locally.

After push:

gh pr checks <PR_NUMBER>        # or: gh run list --branch <branch> --limit 3

Report CI status only after fetching actual results. Never say "CI should be green now" — check and confirm.

Scope discipline

When a working branch grows beyond ~5 logical commits or starts spanning unrelated concerns, proactively propose:

1. A fresh branch off origin/main
2. Cherry-pick only the high-impact, low-blast-radius changes
3. Defer tangential work to follow-up PRs

Don't pile unrelated changes onto an existing branch. Squash fixup commits before pushing.

Multi-flavor device installs

Two app flavors exist: com.geeksville.mesh (fdroid) and com.geeksville.mesh.google (google). Only one can be installed at a time (different signing keys). When switching flavors on a device:

• Uninstall the other flavor first, or the install will fail silently.
• Be aware that uninstalling loses onboarding state, permissions, and bonded-device data. Ask before uninstalling if the user has an active session.

Deeper guidance

Consult .skills/ for detailed playbooks:

• .skills/project-overview/ — Full codebase map and bootstrap
• .skills/kmp-architecture/ — Source-set rules, expect/actual
• .skills/compose-ui/ — Adaptive UI, string resources
• .skills/navigation-and-di/ — Nav 3 & Koin patterns
• .skills/testing-ci/ — CI architecture, verification matrix
• .skills/implement-feature/ — Feature development workflow
• .skills/code-review/ — PR hygiene checklist