Question

Is there a problem with the redundant collection checking here?:

SomeMethod()
{
    shapes = GetShapes();
    //maybe Assert(shapes.Any())?
    if(shapes.Any())
    {
        ToggleVisibility(shapes);
    }
}

ToggleVisibility(IEnumerable<Shape> shapes)
{
    //maybe Assert(shapes.Any())?
    if(shapes.Any())
    {
        //do stuff 
    }
}

Answer 1

I don’t think there’s a big problem here because calling Any() is not an expensive operation.

There is a minor problem in that the responsibility and behavior of ToggleVisibility is not declared. ToggleVisibility should let callers know how it will behave if shapes is empty or null. The best way to do this is through XML comments so that it shows up in Intellisense. This will let ToggleVisibility callers decide if they need to check if the collection is empty or null.