From 86aac58b9e9f73d9eae82359ca2c3d85d40ffa8b Mon Sep 17 00:00:00 2001
From: Claude <noreply@anthropic.com>
Date: Fri, 22 May 2026 21:28:14 +0000
Subject: [PATCH] Validate negative startIndex in ObservableList.RemoveRange

Throw ArgumentOutOfRangeException before taking the lock, matching the
existing count guard, so callers get a deterministic exception instead
of an IndexOutOfRangeException from the per-item read at items[i] =
_list[startIndex + i].
---
 Runtime/Observable/ObservableList.cs | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Runtime/Observable/ObservableList.cs b/Runtime/Observable/ObservableList.cs
index c67034b..f411f22 100644
--- a/Runtime/Observable/ObservableList.cs
+++ b/Runtime/Observable/ObservableList.cs
@@ -168,6 +168,7 @@ public void RemoveAt(int index)
 
         public void RemoveRange(int startIndex, int count)
         {
+            if (startIndex < 0) throw new ArgumentOutOfRangeException(nameof(startIndex));
             if (count < 0) throw new ArgumentOutOfRangeException(nameof(count));
 
             lock (SyncRoot)