Remove LINQ usage from Enum conversion from/to string

CHANGELOG.md

@@ -7,6 +7,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [1.3.1] - 2024-05-20
+
+### Changed
+
+- Updated serialization and deserialization of enums to remove LINQ to resolve NativeAOT compatibility issue
+
 ## [1.3.0] - 2024-05-13
 
 ### Added

src/JsonParseNode.cs

@@ -224,12 +224,21 @@ public JsonParseNode(JsonElement node, KiotaJsonSerializationContext jsonSeriali
             rawValue = ToEnumRawName<T>(rawValue!);
             if(type.GetCustomAttributes<FlagsAttribute>().Any())
             {
-                return (T)(object)rawValue!
-                    .Split(',')
-                    .Select(x => Enum.TryParse<T>(x, true, out var result) ? result : (T?)null)
-                    .Where(x => !x.Equals(null))
-                    .Select(x => (int)(object)x!)
-                    .Sum();
+                ReadOnlySpan<char> valueSpan = rawValue.AsSpan();
+                int value = 0;
+                while(valueSpan.Length > 0)
+                {
+                    int commaIndex = valueSpan.IndexOf(',');
+                    ReadOnlySpan<char> valueNameSpan = commaIndex < 0 ? valueSpan : valueSpan.Slice(0, commaIndex);
+#if NET6_0_OR_GREATER
+                    if(Enum.TryParse<T>(valueNameSpan, true, out var result))
+#else
+                    if(Enum.TryParse<T>(valueNameSpan.ToString(), true, out var result))
+#endif
+                        value |= (int)(object)result;
+                    valueSpan = commaIndex < 0 ? ReadOnlySpan<char>.Empty : valueSpan.Slice(commaIndex + 1);
+                }
+                return (T)(object)value;
             }
             else
                 return Enum.TryParse<T>(rawValue, true,out var result) ? result : null;

src/JsonSerializationWriter.cs

@@ -13,6 +13,8 @@
 using Microsoft.Kiota.Abstractions.Extensions;
 using Microsoft.Kiota.Abstractions;
 using System.Xml;
+using System.Text;
+
 #if NET5_0_OR_GREATER
 using System.Diagnostics.CodeAnalysis;
 #endif
@@ -278,16 +280,25 @@ public void WriteEnumValue<T>(string? key, T? value) where T : struct, Enum
             if(value.HasValue)
             {
                 if(typeof(T).GetCustomAttributes<FlagsAttribute>().Any())
-                    WriteStringValue(null,
+                {
+                    var values =
 #if NET5_0_OR_GREATER
-                        Enum.GetValues<T>()
+                        Enum.GetValues<T>();
 #else
-                        Enum.GetValues(typeof(T))
-                            .Cast<T>()
+                        Enum.GetValues(typeof(T)).Cast<T>();
 #endif
-                            .Where(x => value.Value.HasFlag(x))
-                            .Select(GetEnumName)
-                            .Aggregate((x, y) => $"{x},{y}"));
+                    StringBuilder valueNames = new StringBuilder();
+                    foreach (var x in values)
+                    {
+                        if(value.Value.HasFlag(x) && GetEnumName(x) is string valueName)
+                        {
+                            if (valueNames.Length > 0)
+                                valueNames.Append(",");
+                            valueNames.Append(valueName);
+                        }
+                    }
+                    WriteStringValue(null, valueNames.ToString());
+                }
                 else WriteStringValue(null, GetEnumName(value.Value));
             }
         }

src/Microsoft.Kiota.Serialization.Json.csproj

@@ -15,7 +15,7 @@
     <PackageProjectUrl>https://aka.ms/kiota/docs</PackageProjectUrl>
     <EmbedUntrackedSources>true</EmbedUntrackedSources>
     <Deterministic>true</Deterministic>
-    <VersionPrefix>1.3.0</VersionPrefix>
+    <VersionPrefix>1.3.1</VersionPrefix>
     <VersionSuffix></VersionSuffix>
     <GeneratePackageOnBuild>true</GeneratePackageOnBuild>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>