CreateDerivedCollection ordering bug

[kentcb]

The following test fails:

[Fact]
public void derived_collection_ordering_bug()
{
    var collection = new ReactiveCollection<int>();
    var orderedCollection = collection.CreateDerivedCollection(x => x, null, (x, y) => x.CompareTo(y));

    collection.Add(1);
    collection.Add(2);

    Assert.Equal(2, orderedCollection.Count);
    Assert.Equal(1, orderedCollection[0]);
    Assert.Equal(2, orderedCollection[1]);
}

This is due to the following lines in ReactiveCollection.positionForNewItem:

            if (list.Count == 1) {
                return orderer(list[0], item) >= 0 ? 1 : 0;
            }

I believe it should be:

            if (list.Count == 1) {
                return orderer(list[0], item) >= 0 ? 0 : 1;
            }

which allows the test to pass and upholds the same insertion behavior when items are equal that is exhibited later in the code (ie. new item is inserted before existing item if they are equal).

Alternatively, you could just remove the list.Count == 1 path altogether - seems it's optimizing for the uncommon case to me.

Again, apologies for not being able to submit a pull request - corporate proxy forbids it.

[anaisbetts]

@kentcb Have you tried using an HTTPS remote? If you can sign into GitHub.com, you should be able to push/pull too. Try:

git clone https://github.com/reactiveui/ReactiveUI.git

(If it doesn't work, that's fine too, I just wanted to help you out!)

[kentcb]

Thanks Paul, but:

PS C:\External Code> git clone https://github.com/reactiveui/ReactiveUI.git
Cloning into 'ReactiveUI'...
error: Couldn't resolve host 'github.com' while accessing https://github.com/reactiveui/ReactiveUI.git/info/refs?service=git-upload-pack
fatal: HTTP request failed

And if I try and access that page directly in Chrome, I get "Failed - Blocked".

[anaisbetts]

@kentcb I'll have a look at this at the weekend, thanks for submitting a test and a possible fix!