trail-mate/docs/audits/PHASE6_COMPOSITION_READINESS_REPORT.md

Phase 6 Composition Readiness Report

Decision

Phase 6 is ready to close as a product composition and app shell boundary baseline.

This decision does not mean every target startup path is fully clean. It means object graph ownership is now explicit enough for future phases to build on without expanding global composition drift.

What Phase 6 Established

Phase 6 established the composition boundary above the Phase 5 presentation layer:

Target chooses.
Board describes.
Platform adapts.
Runtime schedules.
Capability provides.
Protocol interprets.
UseCase decides.
AppService coordinates.
PresentationModel projects.
Renderer draws.
CompositionRoot wires.

The new contracts are:

• AppServicesBundle
• PresentationBundle
• ITargetAppShell
• CompositionStatus

These contracts are intentionally small. They are explicit dependency bundles and shell lifecycle contracts, not a replacement service locator.

Composition Roots And Bridges

Target or surface	Phase 6 result
Linux simulator	LinuxSimCompositionRoot owns fake source/sink/model graph and exports PresentationBundle
uConsole	UConsoleCompositionRoot owns Linux app services, uConsole app models, Chat presentation model, and Map presentation binding
ESP LVGL	documented bridge; startup order is not changed in Phase 6
AppContext	documented as LegacyAppContextBridge; new expansion is forbidden

Boundary Rules Now Guarded

Phase 6 checker coverage confirms:

• product_composition contracts do not include platform/toolkit/AppContext runtime headers
• ui_presentation does not import product composition
• AppServicesBundle remains explicit and has no dynamic get<T>()
• PresentationBundle does not construct source/sink/model objects
• Linux simulator and uConsole composition roots exist
• ESP/AppContext bridge audits exist
• known legacy composition surfaces are baseline-recorded

Remaining Legacy Composition Surfaces

The following remain intentionally bounded:

• ESP Arduino AppContext
• ESP-IDF app facade runtime
• global app::appFacade() compatibility pointer
• LVGL Chat page runtime construction of Chat presentation adapters
• LVGL GPS/map page runtime construction of Map presentation adapters
• dashboard GPS widget local presentation bridge
• GTK uConsole app state ownership of legacy app models
• uConsole legacy framebuffer shell service ownership

These are not Phase 6 blockers because they are documented in:

• APPCONTEXT_LEGACY_BRIDGE_AUDIT.md
• ESP_LVGL_COMPOSITION_BRIDGE_AUDIT.md
• phase6_composition_legacy_baseline.json
• PHASE6_COMPOSITION_CONFORMANCE_MATRIX.md

Non-Goals Confirmed

Phase 6 did not:

• remove AppContext
• rewrite ESP startup
• rewrite LVGL pages
• rewrite ChatUiController
• rewrite GPSPageState
• rewrite map tile/cache/contour ownership
• convert target manifests into runtime configuration
• add a new service locator

Phase 6 Exit Criteria

Criterion	Status
Product composition architecture spec exists	pass
Product composition boundary audit exists	pass
product_composition contracts exist	pass
Linux simulator composition root smoke exists	pass
uConsole composition root smoke exists	pass
ESP LVGL composition bridge/audit exists	pass
AppContext bridge audit exists	pass
Phase 6 composition checker exists and passes	pass
PresentationWorkspace construction remains outside ui_presentation	pass
Legacy composition surfaces are baseline-recorded	pass

Phase 7 Input

Future phases may assume:

• Phase 5 presentation boundaries are stable
• target composition roots are the preferred place to create source/sink/model graphs
• renderer/page code should not create new app services
• AppContext is compatibility-only, not the default architecture

Future phases should reduce the baseline one surface at a time, starting with the targets that have clear composition roots: Linux simulator and uConsole.