Bug: Empty Array is projected as null instead of an array of length 0

[kmahone]

Description

Consider the idl:

String[] GetItems();

If the implementation of this function returns an empty array, the CsWinRT projection will return null. But it is expected to return a non-null empty array.

The downside of empty arrays being projected as null is that it forces the consumer to write unnatural code:

string[] items = thing.GetItems();
if (items != null)
{
    foreach (var item in items)
    {
        Console.WriteLine(item);
    }
}

instead of the more idiomatic:

foreach (var item in thing.GetItems())
{
    Console.WriteLine(item);
}

@oldnewthing as FYI.

Steps To Reproduce

See description.

Expected Behavior

See description.

Version Info

2.2.0

Additional Context

No response

[manodasanW]

Looks like the current behavior came from #983 which was done to match pre-existing .NET behavior. But you do make a good point that the foreach syntax is more natural if it wasn't null. Will need to evaluate if we should change this behavior based on seeing what the behavior is if someone passes null from the C# side for an array parameter that goes to native and then possibly round-trips back.