Fix IdentyRef parsing

src/aggregator-webshared/RequestHelper.cs

@@ -108,12 +108,10 @@ static IdentityRef ConvertOrDefault(string input)
                     return null;
                 }
 
-                var uniqueNameLength = uniqueNameEndIndex - uniqueNameStartIndex + 1;
-
                 return new IdentityRef()
                 {
-                    DisplayName = input.Substring(0, uniqueNameStartIndex).Trim(),
-                    UniqueName = new string(input.Skip(uniqueNameStartIndex + 1).Take(uniqueNameLength).ToArray())
+                    DisplayName = input[0..uniqueNameStartIndex].Trim(),
+                    UniqueName = input[(uniqueNameStartIndex + 1)..uniqueNameEndIndex]
                 };
             }
 
@@ -125,13 +123,15 @@ static IdentityRef ConvertOrDefault(string input)
 
             foreach (var identityField in workItem.Fields.Where(field => identityFieldReferenceNameEndings.Any(name => field.Key.EndsWith(name))).ToList())
             {
-                if (identityField.Value is string identityString)
+                IdentityRef identityRef = identityField.Value switch
                 {
-                    workItem.Fields[identityField.Key] = ConvertOrDefault(identityString) ?? identityField.Value;
-                }
-                else if (identityField.Value is JsonElement identityElement)
+                    string identityString => ConvertOrDefault(identityString),
+                    JsonElement identityElement => ConvertOrDefault(identityElement.GetString()),
+                    _ => null
+                };
+                if (identityRef != null)
                 {
-                    workItem.Fields[identityField.Key] = ConvertOrDefault(identityElement.GetString()) ?? identityField.Value;
+                    workItem.Fields[identityField.Key] = identityRef;
                 }
             }
         }

src/unittests-function/RequestHelperTests.cs

@@ -0,0 +1,59 @@
+using System.Collections.Generic;
+using aggregator;
+using Microsoft.Extensions.Logging;
+using Microsoft.TeamFoundation.WorkItemTracking.WebApi.Models;
+using Microsoft.VisualStudio.Services.WebApi;
+using Xunit;
+
+
+namespace unittests_function
+{
+    public class RequestHelperTests
+    {
+        [Fact]
+        public void MigrateIdentityInformationUpdatesIdentityFields()
+        {
+            var logger = NSubstitute.Substitute.For<ILogger>();
+            WorkItem workItem = new WorkItem
+            {
+                Fields = new Dictionary<string, object>
+                {
+                  { "System.WorkItemType", "Bug" },
+                  { "FixedBy", "Jane Doe <jdoe@example.com>" },
+                },
+            };
+
+            new RequestHelper(logger).MigrateIdentityInformation("1.0", workItem);
+
+            var identityValue = workItem.Fields["FixedBy"];
+            Assert.IsType<IdentityRef>(identityValue);
+            Assert.Equal("Jane Doe", ((IdentityRef)identityValue).DisplayName);
+            Assert.Equal("jdoe@example.com", ((IdentityRef)identityValue).UniqueName);
+        }
+
+        [Fact]
+        public void MigrateIdentityInformationDoesNotUpdateStrings()
+        {
+            var logger = NSubstitute.Substitute.For<ILogger>();
+            WorkItem workItem = new WorkItem
+            {
+                Fields = new Dictionary<string, object>
+                {
+                  { "System.WorkItemType", "Bug" },
+                  { "VerifyBy", "GA" },
+                  { "SmileTo", ">_<" },
+                },
+            };
+
+            new RequestHelper(logger).MigrateIdentityInformation("1.0", workItem);
+
+            var stringValue = workItem.Fields["VerifyBy"];
+            Assert.IsType<string>(stringValue);
+            Assert.Equal("GA", stringValue);
+
+            stringValue = workItem.Fields["SmileTo"];
+            Assert.IsType<string>(stringValue);
+            Assert.Equal(">_<", stringValue);
+        }
+    }
+}