Bug: Fuel logs display 0.000 for efficiency and gallons due to DECIMAL type mismatch #49

New Issue

2026-01-18T04:26:10Z

egullickson commented

2026-01-18 04:26:10 +00:00

Summary

The fuel logs screen displays incorrect values:

Total Fuel shows 0.00 gallons instead of actual total
Each entry shows 0.000 @ $0.000 instead of {gallons} @ ${pricePerGallon}
Recent Fuel Logs don't update dynamically when adding new entries

Root Cause Analysis

PostgreSQL DECIMAL columns are returned as strings by the pg driver. The backend toEnhancedResponse() method in fuel-logs.service.ts converts total_cost to a number but not fuel_units or cost_per_unit:

// fuel-logs.service.ts:273-295
private toEnhancedResponse(row: any, efficiency: number | undefined, unitSystem): EnhancedFuelLogResponse {
  return {
    fuelUnits: row.fuel_units,           // NOT converted - arrives as string
    costPerUnit: row.cost_per_unit,      // NOT converted - arrives as string
    totalCost: Number(row.total_cost),   // Converted - works correctly
    // ...
  };
}

Frontend components have defensive checks that fail for strings:

// FuelStatsCard.tsx and FuelLogsList.tsx
const fuelUnits = typeof log.fuelUnits === 'number' ? log.fuelUnits.toFixed(3) : '0.000';

Affected Files

File	Issue
`backend/src/features/fuel-logs/domain/fuel-logs.service.ts:273-295`	Missing `Number()` conversion on `fuel_units` and `cost_per_unit`
`frontend/src/features/fuel-logs/hooks/useFuelLogs.tsx:46-49`	Query invalidation may need review for dynamic updates

Steps to Reproduce

Navigate to Fuel Logs page
Observe Summary shows 0.00 gallons for Total Fuel
Observe each log entry shows 0.000 @ $0.000 instead of actual values
Add a new fuel log entry
Observe the Recent Fuel Logs list doesn't update

Expected Behavior

Summary shows correct total gallons (e.g., 14.5 gallons)
Each entry shows {gallons} @ ${pricePerGallon} (e.g., 5.500 @ $3.459)
Recent Fuel Logs updates immediately when adding new entries

Acceptance Criteria

toEnhancedResponse() converts fuel_units and cost_per_unit to numbers using Number()
Summary card displays correct total fuel units
Log entries display correct gallons and price per gallon
Adding a new fuel log immediately updates the Recent Fuel Logs list
All existing tests pass
No TypeScript errors

Technical Notes

The getVehicleStats() method already handles this correctly with Number(r.fuel_units)
The fix should follow the same pattern as totalCost: Number(row.total_cost)
Review useFuelLogs.tsx mutation onSuccess to ensure proper query invalidation

## Summary The fuel logs screen displays incorrect values: - **Total Fuel** shows `0.00 gallons` instead of actual total - **Each entry** shows `0.000 @ $0.000` instead of `{gallons} @ ${pricePerGallon}` - **Recent Fuel Logs** don't update dynamically when adding new entries ## Root Cause Analysis PostgreSQL DECIMAL columns are returned as strings by the `pg` driver. The backend `toEnhancedResponse()` method in `fuel-logs.service.ts` converts `total_cost` to a number but not `fuel_units` or `cost_per_unit`: ```typescript // fuel-logs.service.ts:273-295 private toEnhancedResponse(row: any, efficiency: number | undefined, unitSystem): EnhancedFuelLogResponse { return { fuelUnits: row.fuel_units, // NOT converted - arrives as string costPerUnit: row.cost_per_unit, // NOT converted - arrives as string totalCost: Number(row.total_cost), // Converted - works correctly // ... }; } ``` Frontend components have defensive checks that fail for strings: ```typescript // FuelStatsCard.tsx and FuelLogsList.tsx const fuelUnits = typeof log.fuelUnits === 'number' ? log.fuelUnits.toFixed(3) : '0.000'; ``` ## Affected Files | File | Issue | |------|-------| | `backend/src/features/fuel-logs/domain/fuel-logs.service.ts:273-295` | Missing `Number()` conversion on `fuel_units` and `cost_per_unit` | | `frontend/src/features/fuel-logs/hooks/useFuelLogs.tsx:46-49` | Query invalidation may need review for dynamic updates | ## Steps to Reproduce 1. Navigate to Fuel Logs page 2. Observe Summary shows `0.00 gallons` for Total Fuel 3. Observe each log entry shows `0.000 @ $0.000` instead of actual values 4. Add a new fuel log entry 5. Observe the Recent Fuel Logs list doesn't update ## Expected Behavior - Summary shows correct total gallons (e.g., `14.5 gallons`) - Each entry shows `{gallons} @ ${pricePerGallon}` (e.g., `5.500 @ $3.459`) - Recent Fuel Logs updates immediately when adding new entries ## Acceptance Criteria - [ ] `toEnhancedResponse()` converts `fuel_units` and `cost_per_unit` to numbers using `Number()` - [ ] Summary card displays correct total fuel units - [ ] Log entries display correct gallons and price per gallon - [ ] Adding a new fuel log immediately updates the Recent Fuel Logs list - [ ] All existing tests pass - [ ] No TypeScript errors ## Technical Notes - The `getVehicleStats()` method already handles this correctly with `Number(r.fuel_units)` - The fix should follow the same pattern as `totalCost: Number(row.total_cost)` - Review `useFuelLogs.tsx` mutation `onSuccess` to ensure proper query invalidation

egullickson added the

labels 2026-01-18 04:26:15 +00:00

egullickson added

and removed