# Troubleshooting and Quality Gates

## Troubleshooting

### Upload Errors

- Validate extension and size before storage.
- Catch expected exceptions and return negative notifications.
- Log unexpected exceptions with request context.

### UI Race Conditions

- Disable triggering controls during async work.
- Remove duplicate timers and listeners targeting the same state.
- Ensure service call ordering is deterministic before render updates.

### Asset Caching

- Confirm static mount and proxy rewrite correctness.
- Add cache-busting query strings for changed assets.
- Avoid per-page CSS injection.

### Navigation and State Drift

- Avoid global mutable UI state.
- Keep state request-scoped or service-managed.
- Rehydrate page data during route load.

## Production Readiness Gate

Pass all checks before shipping:

- Structure: one-way dependencies between pages, components, and services.
- Responsiveness: UI validated at both small and large viewport widths.
- Accessibility: labels and actions are clear and readable.
- Reliability: validation and exception paths surface user feedback.
- Maintainability: repeated UI patterns are extracted; business logic remains in services.

If any check fails, return to the workflow step that owns that concern.