IComparer.Compare exception

[JohnBonnett88]

Hi All,

I have had an odd problem in a VO X# system and have tracked it down to an ASort call that is failing. I have not so far been able to pin down the problem. I am sorting an array of 2-element arrays and it is sorting by comparing the first element of each of those sub-arrays. I think there are better ways of doing what the code is trying to do but, although the data has a fair bit of duplication, sorting should still work.

I made a small X# WinForms app, VO dialect, and replaced the programs.prg with the following code for testing:

Code: Select all

USING System
USING System.Collections.Generic
USING System.Linq
USING System.Text
USING System.Windows.Forms

USING TestFWXS

[STAThread] ;
FUNCTION Start() AS VOID
    LOCAL T, S AS ARRAY
    LOCAL I AS DWORD
    
    T := {{1,27},{2,6},{1,27},{2,6},{1,27},{2,6},{1,27},{2,6},{1,27},{2,6},{1,27},{2,6},{1,27},{2,6},{1,28},{2,3},{1,28},{2,3},{1,27},{2,6},{1,27},{2,6}}    
    FOR I := 1 UPTO ALen(T)
        S := ASize(AClone(T), I)
        ASort(S, , , {|x, y| x[1] <= y[1]})
    NEXT
    RETURN

The original problem occurred with an 18 element array and the array T above is an extended version of that. I copied the first 4 elements onto the end to extend it, but otherwise the data is the same. The code creates subsets of that T array and tries to sort them. All goes well until you get to 17 elements when it fails with:

System.ArgumentException
HResult=0x80070057
Message=Unable to sort because the IComparer.Compare() method returns inconsistent results. Either a value does not compare equal to itself, or one value repeatedly compared to another value yields different results. IComparer: 'XSharp.RT.ArraySortComparer'.
Source=mscorlib
StackTrace:
at System.Collections.Generic.IntrospectiveSortUtilities.ThrowOrIgnoreBadComparer(Object comparer)
at System.Collections.Generic.GenericArraySortHelper`1.Sort(T[] keys, Int32 index, Int32 length, IComparer`1 comparer)
at System.Array.Sort[T](T[] array, Int32 index, Int32 length, IComparer`1 comparer)
at System.Collections.Generic.List`1.Sort(Int32 index, Int32 count, IComparer`1 comparer)
at XSharp.__Array.Sort(Int32 startIndex, Int32 count, IComparer`1 comparer)
at XSharp.RT.Functions.ASort(__Array aTarget, __Usual nStart, __Usual nCount, __Usual cbOrder)
at TestFWXS.Exe.Functions.Start() in C:\Users\XVJBONNE\source\repos\LabPro\TestFWXS\Program.prg:line 17

It is complaining that the comparer defined in the code block is faulty. It seems to fail with 17 or more elements. I will try over the weekend to debug it with the GitHub code for ASort to see if I can refine it further.

Any suggestions?

John Bonnett

[JohnBonnett88]

Just a follow-up to my previous message, in case it matters, I am running:

Microsoft Visual Studio Professional 2022 (64-bit) - Current Version 17.13.6
X# Visual Studio Project System - 2.21.0.5
Windows 11 Enterprise Version 22H2 OS build 22621.5189
Intel(R) Core(TM) i7-10850H CPU @ 2.70GHz 2.71 GHz

[HansjoergP]

Hello,

this is the issue
https://github.com/X-Sharp/XSharpPublic/issues/1653

[robert]

John
This is fixed in the runtime update.
It will also be included in the upcoming new release.

Robert

[JohnBonnett88]

Thanks for everyone's replies.

I have applied the workaround suggested in the GitHub issue and my test example now works. I have applied the same fix as required in my main solution.

I must remember to check GitHub before bothering people on this forum!

Thanks again,
John

[robert]

John,

Thanks for everyone's replies.

I have applied the workaround suggested in the GitHub issue and my test example now works. I have applied the same fix as required in my main solution.

I must remember to check GitHub before bothering people on this forum!

I am not sure if you are using X# for your business or hobby.
If it is for your business, then why not support the project and become a subscriber?
That would have saved you some time, and you would also show your support for this project that has helped you move your VO application forward.

Robert