Add funciton to handle duplicate naming

com.unity.shadergraph/Editor/Data/Util/GraphUtil.cs

-using System;
+using System;
+using System.Text.RegularExpressions;
 using UnityEditor.Graphing;
 using UnityEditor.Graphing.Util;
 using UnityEngine;
             }
 
             return s_LegacyTypeRemapping;
+        }
+
+        // Sanitize a name to not conflict with other names.
+        // `existingNames` is the collection of names that the sanitized name should not collide with.
+        // `duplicateFormat` is the format applied to handle cases with overlapping names. The string supplied should
+        // be a formattable string where the first argument is the base name, and the second argument the
+        // `duplication number`.
+        // An example of input ({"name", "name (1)"}, "{0} ({1})", name) should yield the output "name (2)".
+        public static string SanitizeName(IEnumerable<string> existingNames, string duplicateFormat, string name)
+        {
+            if (!existingNames.Contains(name))
+                return name;
+
+            string escapedDuplicateFormat = Regex.Escape(duplicateFormat);
+
+            // Escaped format will escape string interpolation, so the escape caracters must be removed for these.
+            escapedDuplicateFormat = escapedDuplicateFormat.Replace(@"\{0}", @"{0}");
+            escapedDuplicateFormat = escapedDuplicateFormat.Replace(@"\{1}", @"{1}");
+
+            var baseRegex = new Regex(string.Format(escapedDuplicateFormat, @"^(.*)", @"(\d+)"));
+
+            var baseMatch = baseRegex.Match(name);
+            if (baseMatch.Success)
+                name = baseMatch.Groups[1].Value;
+
+            string baseNameExpression= string.Format(@"^{0}", Regex.Escape(name));
+            var regex = new Regex(string.Format(escapedDuplicateFormat, baseNameExpression, @"(\d+)") + "$");
+
+            var existingDuplicateNumbers = existingNames.Select(existingName => regex.Match(existingName)).Where(m => m.Success).Select(m => int.Parse(m.Groups[1].Value)).Where(n => n > 0).Distinct().ToList();
+
+            var duplicateNumber = 1;
+            existingDuplicateNumbers.Sort();
+            if (existingDuplicateNumbers.Any() && existingDuplicateNumbers.First() == 1)
+            {
+                duplicateNumber = existingDuplicateNumbers.Last() + 1;
+                for (var i = 1; i < existingDuplicateNumbers.Count; i++)
+                {
+                    if (existingDuplicateNumbers[i - 1] != existingDuplicateNumbers[i] - 1)
+                    {
+                        duplicateNumber = existingDuplicateNumbers[i - 1] + 1;
+                        break;
+                    }
+                }
+            }
+
+            return string.Format(duplicateFormat, name, duplicateNumber);
         }
     }
 }