Problem Statement

Problem Statement

The company is building an interactive Office Hot-Desking Map. Employees view a grid representation of an office floor, see desk statuses in real time, and click to reserve spots. The core backend works, but it has three problems.

1. Adjacent-seat race conditions

Each booking is checked against the desks next to it before it's saved. When two employees reserve neighbouring desks for the same day at the same moment, both requests can pass that check before either is saved. Both succeed, and the spacing rule is broken.

This is a write skew race. The two requests insert rows for different desks, so a unique constraint or a lock on only the desk being booked can't stop it. See Booking Concurrency for a step-by-step walk-through and the fix.

Expected: among conflicting concurrent requests, exactly one succeeds. The others get a clear conflict error (HTTP 409).

2. Invalid spatial isolation selections

The backend accepts reservations that break the spacing rule, for example booking a desk directly next to one already reserved for the same day.

Expected: the server rejects every booking that would place two booked desks next to each other on the same day, using the floor's neighbour setting (ORTHOGONAL or ALL). The frontend may warn early, but the server's check is what counts. See Domain Rules.

3. No fluid matrix updates on the frontend

The map doesn't update smoothly when desk statuses change. It needs a manual refresh, or it re-renders the whole grid instead of just the changed desk.

Expected:

• Status changes reach every open map within moments.
• Only the affected cells redraw.
• The map recovers correctly after a dropped connection.
• The map never shows a booking the server rolled back or rejected.

See Real-Time Updates and Frontend Design.