perf: replace SubsString with alternative lookup (#4280)

TimothyMakkison · web-flow · commit 2809adea662c · 2026-01-10T18:03:27.000Z
diff --git a/TUnit.Core/Discovery/ObjectGraphDiscoverer.cs b/TUnit.Core/Discovery/ObjectGraphDiscoverer.cs
@@ -651,8 +651,13 @@ private static bool IsDirectProperty(string cacheKey, HashSet<string> hierarchyT
             return true; // Malformed key, treat as direct
         }
 
+#if NET9_0_OR_GREATER
+        var declaringTypeName = cacheKey.AsSpan()[..lastDotIndex];
+        return hierarchyTypes.GetAlternateLookup<ReadOnlySpan<char>>().Contains(declaringTypeName);
+#else
         var declaringTypeName = cacheKey.Substring(0, lastDotIndex);
         return hierarchyTypes.Contains(declaringTypeName);
+#endif
     }
 
     /// <summary>

Original file line number	Diff line number	Diff line change
`@@ -651,8 +651,13 @@ private static bool IsDirectProperty(string cacheKey, HashSet<string> hierarchyT`
`651`	`651`	`return true; // Malformed key, treat as direct`
`652`	`652`	`}`
`653`	`653`
	`654`	`+#if NET9_0_OR_GREATER`
	`655`	`+ var declaringTypeName = cacheKey.AsSpan()[..lastDotIndex];`
	`656`	`+ return hierarchyTypes.GetAlternateLookup<ReadOnlySpan<char>>().Contains(declaringTypeName);`
	`657`	`+#else`
`654`	`658`	`var declaringTypeName = cacheKey.Substring(0, lastDotIndex);`
`655`	`659`	`return hierarchyTypes.Contains(declaringTypeName);`
	`660`	`+#endif`
`656`	`661`	`}`
`657`	`662`
`658`	`663`	`/// <summary>`