Cursor creation fails on a dataview with sparse vectors

[xadupre]

System information

• Windows 10.0.17134:
• .NET Version 2.1.301:

Issue

• The creation of a cursor on a dataview with sparse vectors does not work anymore.
• Expected getter type is VBuffer, produced getter type is VBuffer<VBuffer>.

Source code / logs

The following code fails.

class ExampleASparse
{
[VectorType(5)]
public VBuffer X;
}

    [Fact]
    [TestCategory(Cat)]
    public void SparseDataView()
    {
        var inputs = new[] {
            new ExampleASparse() { X = new VBuffer<float> (5, 3, new float[] { 1, 10, 100 }, new int[] { 0, 2, 4 }) },
            new ExampleASparse() { X = new VBuffer<float> (5, 3, new float[] { 2, 3, 5 }, new int[] { 0, 1, 3 }) }
        };
        var host = new TlcEnvironment();
        var data = host.CreateStreamingDataView(inputs);
        VBuffer<float> value = new VBuffer<float>();
        int n = 0;
        using (var cur = data.GetRowCursor(i => true)) // it fails here
        {
            var getter = cur.GetGetter<VBuffer<float>>(0);
            while (cur.MoveNext())
            {
                getter(ref value);
                Assert.True(value.Count == 3);
                ++n;
            }
        }
        Assert.True(n == 2);
        Done();
    }