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TreeSubSet.Min and TreeSubSet.Max work incorrectly with custom comparer #54834
Description
Description
The code below gives the wrong result:
var comparer = Comparer<int>.Create((x, y) => x - y);
var set = new SortedSet<int>(new[]{1, 4}, comparer);
var view = set.GetViewBetween(1, 2);
Console.WriteLine(view.Max); // Prints 4 instead of 1
According to the documentation of IComparer.Compare() it can return any integer, not only [-1, 0, 1]. So this comparer should be ok.
Configuration
I run it on .net 5, but I think it is present in other versions as well.
Regression?
A similar issue was mentioned in 20474 (without comparer though). So I think it is regression.
Other information
I have found the reason why it happens in code:
The comparison result is checked against 1 and -1, instead of (comp > 0) and (comp < 0).
Activity
eiriktsarpalis commentedon Jun 28, 2021
This seems like a bug introduced by dotnet/corefx#16771. It seems like a trivial fix, would you be willing to contribute a PR?
petrogavriluk commentedon Jun 28, 2021
I haven't contributed here yet, but yes, I can try.
Should I also add tests?
eiriktsarpalis commentedon Jun 28, 2021
Thanks, assigning the issue to you. A couple of tests reproducing your scenario for both min and max should suffice.
Please let me know if you have any questions on the dev workflow.
Fix incorrect comparison (dotnet#54834)
Fix incorrect comparison (#54834) (#55094)