[Bug?] When `Maybe<T>` has a default value, the result is Maybe.HasValue == true

[Jeff Ward]

Hello all,

I was doing some work, and I discovered this strange bug, at least i'd call it a bug. In my opinion, null and default are both no value. When an object is set to default, the value is none, it just is the object itself. Thats why 0 == defaullt(int).

I ran into the case where I would like Guid.Empty == Maybe.None, however that is not the case. Please see below:

   [Fact]
    public void MaybeShouldBeNone_GuidEmpty()
    {
        Maybe<Guid> shouldBeEmpty = Guid.Empty;
        Assert.True(0 == default(int));
        Assert.True(Guid.Empty == default);
        
        // This fails
        Assert.True(shouldBeEmpty.HasNoValue);
    }

Is this by design?

[rutkowskit]

I do not think it is a bug. Maybe protects against null values, not the default values.
Let's say we have int instead of Guid. Maybe<int> = 0; is a valid value, even though 0 is the default value of an int variable.

If you need validation against the default value, You can use something like this:

var result = Result.Success(Guid.Empty)
   .Ensure(guid => guid != default, "Guid is not set");
Assert.True(result.IsFailure);

[Jeff Ward]

@rutkowskit - Thanks for this, this makes sense. I think in my head its the distinction between null and empty, and I for some reason was under the impression that Maybe<T> also worked for empty

Thanks for the example also!