Architecture patterns and transaction boundaries

Understand MVVM, explicit dependencies and transaction boundaries for cancellable operations and reliable state commits.

MVVM and interactions

ViewModels own semantic state/cancellable commands; views own controls/themes. Interaction services create dialogs on the UI thread, serialize display and return choices. Domain outcomes do not depend on brushes. Cancel stale queries before they overwrite current selection.

Dependencies and lifetime

Static Host façades such as ConfigService coexist with instance HistoryRuntime/plugin sessions/indexes/transports/operation services. Do not make load contexts/gates/cancellation sources unbounded global state.

Atomic commit and recovery

Config snapshots serialize writes; a Commit Pack atomically exposes transaction facts. Indexes are rebuildable; Workspace/Replica Catalog are device-local. Config gates/final Guards revalidate identities/revisions, preserving committed semantics after faults.

Journals, isolated staging/quarantine and idempotent compensation handle interruptions. Catching an exception and continuing writes is not success. Keep stage diagnostics/cancellation; RecoveryRequired blocks destructive work.

Proposals and immutable extensions

Discovery/reconciliation return drafts/patches for Host persistence. Artifact transactions append nodes; materializers write isolated workspaces. Snapshots/proposals/validation/commit replace ordered hooks and writable Host models.