Unboundlocalerror: Local Variable 'prod_available' Referenced Before Assignment

I am developing a reservation system, and i have a function that save the quantity of a product... My question is why I got this problem ? when i `curl -l -X POST -d 'product=3&am

Solution 1:

Sometimes you loop is not entered, so prod_Available is not created, but you try to reference it.

Before the loop put prod_Available = 0:

    prod = Product.objects.get(id=product_id)

    prod_Available = 0# !for x inrange(start_date,end_date + 1):
        x = x - start_date
        delta = datetime.timedelta(days=x)
        all_date = check_in + delta
        sumOfQuantity = HotelCheck.objects.filter(date_booked=all_date, product=prod).aggregate(Sum('quantity'))['quantity__sum']
        if sumOfQuantity == None:
            sumOfQuantity = 0
        prod_Available = prod.quantity - sumOfQuantity
        #global prod_Availableif prod_Available <= 0:
        status = 0else:
        status = 1return status

Solution 2:

Just initialize prod_Available to Zero before the following for statement

for x in range(start_date,end_date + 1): 

It so happens that because you are assigning value to prod_Available inside the loop, there is a possibility that the variable is never assigned and the following if statement would fail.

ifprod_Available<=0:

Instead, doing

prod_Available =0  #Initialize outside loop
for x in range(start_date,end_date + 1): 

would resolve your issue

Solution 3:

You are getting different behaviours due to passing in different values.

For the first call, you are passing check_in='2011-12-15' and check_out='2011-12-10' and for the second, you have checkin='2011-12-10', and checkout='2011-12-15'. I.e, the check in and check out values are swapped.

This means that the for x in range(start_date,end_date + 1): loop will never get executed, thus never setting prod_Available.

There are two obvious fixes here:

1. Improve parameter validation, and report an error if the check out date is before the check in date.

2. Set prod_Available to zero before you start the loop. This will ensure that it is always set, even if the loop does not execute.