chore: additional debugging to try to track down FreeSegment issues (#781)

Runtime/ArmatureAwase/AllocationMap.cs

@@ -2,6 +2,8 @@
 
 using System;
 using System.Collections.Generic;
+using System.Runtime.CompilerServices;
+using UnityEngine;
 
 #endregion
 
@@ -102,7 +104,13 @@ namespace nadena.dev.modular_avatar.core.armature_lock
             if (s == null) throw new ArgumentException("Passed a foreign segment???");
 
             int index = segments.BinarySearch(s, Comparer<Segment>.Create((a, b) => a._offset.CompareTo(b._offset)));
-            if (index < 0 || segments[index] != s) throw new Exception("Segment not found in FreeSegment");
+            if (index < 0 || segments[index] != s)
+            {
+                var segmentDump = string.Join("\n", segments.ConvertAll(seg => $"{seg._offset} {seg._length} {seg._inUse} id={RuntimeHelpers.GetHashCode(seg)}"));
+                segmentDump += "\n\nTarget segment " + s._offset + " " + s._length + " " + s._inUse + " id=" + RuntimeHelpers.GetHashCode(s);
+                
+                throw new Exception("Segment not found in FreeSegment\nCurrent segments:\n" + segmentDump);
+            }
 
             if (index == segments.Count - 1)
             {

UnitTests~/ArmatureAwase/AllocationMapTest.cs

@@ -1,4 +1,5 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 using nadena.dev.modular_avatar.core.armature_lock;
 using NUnit.Framework;
 
@@ -66,6 +67,64 @@ namespace UnitTests.ArmatureAwase
             AssertSegment(s4, 0, 20, true);
         }
 
+        enum Op
+        {
+            Allocate, Deallocate, Defrag
+        }
+
+        [Test]
+        public void SegmentRandomOps()
+        {
+            for (int i = 0; i < 1000; i++)
+            {
+                AllocationMap map = new AllocationMap();
+                
+                List<ISegment> segments = new List<ISegment>();
+                List<(Op, int)> ops = new List<(Op, int)>();
+
+                try
+                {
+                    Random r = new Random();
+                    for (int j = 0; j < 100; j++)
+                    {
+                        switch (r.Next(0, segments.Count == 0 ? 1 : 3))
+                        {
+                            case 0:
+                            {
+                                int segSize = r.Next(1, 16);
+                                ISegment s = map.Allocate(segSize);
+                                ops.Add((Op.Allocate, segSize));
+                                segments.Add(s);
+                                break;
+                            }
+                            case 1:
+                            {
+                                int idx = r.Next(0, segments.Count);
+                                ISegment s = segments[idx];
+                                map.FreeSegment(s);
+                                ops.Add((Op.Deallocate, idx));
+                                segments.RemoveAt(idx);
+                                break;
+                            }
+                            case 2:
+                            {
+                                ops.Add((Op.Defrag, 0));
+                                map.Defragment((src, dst, length) => {});
+                                break;
+                            }
+
+                        }
+                    }
+                }
+                catch (Exception e)
+                {
+                    var trace = string.Join("\n", ops.ConvertAll(op => $"{op.Item1} {op.Item2}"));
+                    Assert.Fail($"Failed at iteration {i} with exception {e}\n{trace}");
+                    throw;
+                }
+            }
+        }
+
         private void AssertSegment(ISegment segment, int offset, int length, bool inUse)
         {
             var s = segment as AllocationMap.Segment;