Fixing #6269 by comparing PremiereDate when episode comparison would otherwise be equal.

Emby.Server.Implementations/Sorting/AiredEpisodeOrderComparer.cs

@@ -28,16 +28,6 @@ namespace Emby.Server.Implementations.Sorting
                 throw new ArgumentNullException(nameof(y));
             }
 
-            if (x.PremiereDate.HasValue && y.PremiereDate.HasValue)
-            {
-                var val = DateTime.Compare(x.PremiereDate.Value, y.PremiereDate.Value);
-
-                if (val != 0)
-                {
-                    // return val;
-                }
-            }
-
             var episode1 = x as Episode;
             var episode2 = y as Episode;
 
@@ -156,8 +146,16 @@ namespace Emby.Server.Implementations.Sorting
         {
             var xValue = ((x.ParentIndexNumber ?? -1) * 1000) + (x.IndexNumber ?? -1);
             var yValue = ((y.ParentIndexNumber ?? -1) * 1000) + (y.IndexNumber ?? -1);
+            var compare_val = xValue.CompareTo(yValue);
+            if (compare_val == 0)
+            {
+                if (x.PremiereDate.HasValue & y.PremiereDate.HasValue)
+                {
+                    compare_val = DateTime.Compare(x.PremiereDate.Value, y.PremiereDate.Value);
+                }
+            }
 
-            return xValue.CompareTo(yValue);
+            return compare_val;
         }
 
         /// <summary>

tests/Jellyfin.Server.Implementations.Tests/Sorting/AiredEpisodeOrderComparerTests.cs

@@ -172,6 +172,25 @@ namespace Jellyfin.Server.Implementations.Tests.Sorting
                     new Episode { ParentIndexNumber = 0, IndexNumber = 1, AirsBeforeSeasonNumber = 1, AirsBeforeEpisodeNumber = 2 },
                     1
                 };
+                // Premiere Date
+                yield return new object?[]
+                {
+                    new Episode { ParentIndexNumber = 1, IndexNumber = 1, PremiereDate = new DateTime(2021, 09, 12, 0, 0, 0) },
+                    new Episode { ParentIndexNumber = 1, IndexNumber = 1, PremiereDate = new DateTime(2021, 09, 12, 0, 0, 0) },
+                    0
+                };
+                yield return new object?[]
+                {
+                    new Episode { ParentIndexNumber = 1, IndexNumber = 1, PremiereDate = new DateTime(2021, 09, 11, 0, 0, 0) },
+                    new Episode { ParentIndexNumber = 1, IndexNumber = 1, PremiereDate = new DateTime(2021, 09, 12, 0, 0, 0) },
+                    -1
+                };
+                yield return new object?[]
+                {
+                    new Episode { ParentIndexNumber = 1, IndexNumber = 1, PremiereDate = new DateTime(2021, 09, 12, 0, 0, 0) },
+                    new Episode { ParentIndexNumber = 1, IndexNumber = 1, PremiereDate = new DateTime(2021, 09, 11, 0, 0, 0) },
+                    1
+                };
             }
 
             IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();