Implement two-step flag toggle with confirmation dialog
epic-organization-feature-flags-ui-task-004 — Build the deliberate two-step toggle flow for the admin screen: first tap stages the toggle, second tap opens a confirmation dialog displaying a plain-language impact description for that flag (e.g., 'Enabling this will allow HLF members to submit travel reimbursement requests'). On confirm, dispatch the toggle action through FeatureFlagProvider and persist via FeatureFlagRepository. On cancel, revert staged state.
Acceptance Criteria
Technical Requirements
Execution Context
Tier 2 - 518 tasks
Can start after Tier 1 completes
Implementation Notes
Model the toggle state as a local StateProvider
Guard against the widget being unmounted while the persist call is in-flight by checking mounted before calling setState or ref.read.
Testing Requirements
Write Flutter widget tests using flutter_test and ProviderScope overrides. Test cases: (1) first tap sets staged state without calling repository; (2) second tap opens confirmation dialog; (3) confirm dispatches toggle and closes dialog; (4) cancel reverts staged state and closes dialog; (5) repository failure rolls back toggle and shows error snackbar; (6) double-tap on confirm button does not issue two repository calls; (7) dialog impact description is visible and non-empty. Achieve 100% branch coverage on the staged-state machine. Use mockito or mocktail to mock FeatureFlagRepository.
The feature flag admin screen allows persisting changes to organization_configs. If the role guard is implemented only client-side (checking role state in Riverpod), a user who manipulates their local role state could toggle flags for their organization without proper server-side authorization, potentially exposing features prematurely.
Mitigation & Contingency
Mitigation: Implement server-side authorization for flag update operations using Supabase RLS UPDATE policies that check the user's role in the memberships table. The client-side guard is UX only; the database enforces the actual restriction.
Contingency: If an unauthorized update is detected, audit the RLS policies and add a Supabase Edge Function as an authorization middleware for flag toggle operations, rejecting requests from non-admin role JWTs.
Developers on other feature teams may use FeatureGate incorrectly — for example, wrapping business logic rather than UI, or using it before flag initialization completes — leading to features that are visible but non-functional or cause runtime errors when flags are queried in a loading state.
Mitigation & Contingency
Mitigation: Add assert statements in FeatureGate's build method that throw in debug mode if the provider is still in a loading state. Write developer documentation with a clear usage contract: FeatureGate is UI-only; logic gating must use the provider's isEnabled method directly. Include lint examples in the codebase.
Contingency: If misuse is found in code reviews, add a custom Dart lint rule via custom_lint that flags FeatureGate usage outside of the widget tree, and conduct a codebase audit to find existing violations.
If the audit log is stored in the same organization_configs table without pagination or archival strategy, high-frequency flag changes during pilot testing could produce an unbounded number of rows, degrading query performance on the admin screen.
Mitigation & Contingency
Mitigation: Store audit log entries in a separate feature_flag_audit_log table with an index on (organization_id, changed_at DESC). Implement cursor-based pagination in the repository and limit the initial load to 50 entries.
Contingency: If table size becomes a performance concern, add a Supabase scheduled function to archive entries older than 90 days to cold storage, and add a database index on changed_at for range queries.