Checking C# new() initialisation for null?

Question

I've found this piece of code on Koders:

private ServiceProvider SiteServiceProvider
{
    get
    {
        if (serviceProvider == null)
        {
            serviceProvider = new ServiceProvider(site as VSOLE.IServiceProvider);
            Debug.Assert(serviceProvider != null, "Unable to get ServiceProvider from site object.");
        }
        return serviceProvider;
    }
}

I'm wondering, is there any possible way the Debug.Assert(serviceProvider != null could trigger? I'm under the impression that new could only be aborted by an exception, in which case the assert would never be reached.

Answer 1

It's possible that the ServiceProvider overrides the !=/== operator, so that for an invalid state the comparison to null returns true.

Looks strange anyway.

Answer 2

I would expect that "test for null" pattern more if it was a factory method - i.e.

SomeType provider = SomeFactory.CreateProvider();
if(provider == null) // damn!! no factory implementation loaded...
{ etc }

There is one other case worth knowing about, but which doesn't apply here (since we know the type we are creating)... Nullable<T>; this is mainly an issue with generics:

static void Test<T>() where T : new()
{
    T x = new T();
    if (x == null) Console.WriteLine("wtf?");
}
static void Main()
{
    Test<int?>();
}

This is covered more here.