Flow complexity (ARCH714)

Key dotnet.codequality.flow-complexity · Severity warning · Category codequality

Flags a method whose branches and loops are nested so deeply that a reader has to keep several conditions in mind at once. Each if, loop, catch, switch and ternary costs one plus one per level it is nested at; else and else-if cost one; a run of the same && or || costs one; a method calling itself costs one. Reported above 15.

Incorrect

foreach (var order in orders)
{
    if (order.IsPaid)
    {
        foreach (var line in order.Lines)
        {
            if (line.Stock > 0 && line.Active)
            {
                try { Ship(line); }
                catch (Exception) { if (retry) Queue(line); else Fail(line); }
            }
        }
    }
}

Correct

foreach (var order in orders.Where(o => o.IsPaid))
    ShipLines(order);

void ShipLines(Order order)
{
    foreach (var line in order.Lines.Where(IsShippable))
        TryShip(line);
}