From fc593926cf5cc4bbd56338973318047ae8f28cba Mon Sep 17 00:00:00 2001
From: Thomas Farr <tsfarr@amazon.com>
Date: Fri, 20 Sep 2024 14:55:00 +1200
Subject: [PATCH] Fix enum parsing

Signed-off-by: Thomas Farr <tsfarr@amazon.com>
---
 src/OpenSearch.Net/Api/Enums.cs               |  4 +-
 src/OpenSearch.Net/OpenSearch.Net.csproj      |  1 +
 .../ClientConcepts/Enums/EnumParsingTests.cs  | 62 +++++++++++++++++++
 3 files changed, 65 insertions(+), 2 deletions(-)
 create mode 100644 tests/Tests/ClientConcepts/Enums/EnumParsingTests.cs

diff --git a/src/OpenSearch.Net/Api/Enums.cs b/src/OpenSearch.Net/Api/Enums.cs
index 6a07648f1a..be5dbe344b 100644
--- a/src/OpenSearch.Net/Api/Enums.cs
+++ b/src/OpenSearch.Net/Api/Enums.cs
@@ -90,7 +90,7 @@ private static Func<Enum, string> GetEnumStringResolver(Type type)
                 : e => dictionary[e];
 		}
 
-        public static TEnum Parse<TEnum>(string value)
+        internal static TEnum Parse<TEnum>(string value)
             where TEnum : struct, Enum
         {
             var parser = EnumStringParsers.GetOrAdd(typeof(TEnum), GetEnumStringParser);
@@ -113,7 +113,7 @@ private static Func<string, Enum> GetEnumStringParser(Type type)
             var isFlag = type.GetCustomAttributes(typeof(FlagsAttribute), false).Length > 0;
 
             return isFlag
-                ? s => (Enum) Convert.ChangeType(s.ToLowerInvariant().Split(',').Aggregate(0ul, (acc, value) => acc | Convert.ToUInt64(dictionary[value])), type)
+                ? s => (Enum)Enum.ToObject(type, s.ToLowerInvariant().Split(',').Aggregate(0, (acc, value) => acc | Convert.ToInt32(dictionary[value])))
                 : s => dictionary[s.ToLowerInvariant()];
         }
 	}
diff --git a/src/OpenSearch.Net/OpenSearch.Net.csproj b/src/OpenSearch.Net/OpenSearch.Net.csproj
index 155b16c0fd..fe4682bf85 100644
--- a/src/OpenSearch.Net/OpenSearch.Net.csproj
+++ b/src/OpenSearch.Net/OpenSearch.Net.csproj
@@ -41,6 +41,7 @@
     <InternalsVisibleTo Include="OpenSearch.Net.DynamicObjectResolverAllowPrivateFalseExcludeNullTrueNameMutateSnakeCase" Key="$(ExposedPublicKey)" />
     
     <InternalsVisibleTo Include="Tests" Key="$(ExposedPublicKey)" />
+    <InternalsVisibleTo Include="Tests.YamlRunner" Key="$(ExposedPublicKey)" />
 
   </ItemGroup>
   <ItemGroup>
diff --git a/tests/Tests/ClientConcepts/Enums/EnumParsingTests.cs b/tests/Tests/ClientConcepts/Enums/EnumParsingTests.cs
new file mode 100644
index 0000000000..be0e0487b4
--- /dev/null
+++ b/tests/Tests/ClientConcepts/Enums/EnumParsingTests.cs
@@ -0,0 +1,62 @@
+/* SPDX-License-Identifier: Apache-2.0
+*
+* The OpenSearch Contributors require contributions made to
+* this file be licensed under the Apache-2.0 license or a
+* compatible open source license.
+*/
+
+using System;
+using System.Runtime.Serialization;
+using FluentAssertions;
+using OpenSearch.Net;
+using OpenSearch.OpenSearch.Xunit.XunitPlumbing;
+
+namespace Tests.ClientConcepts.Enums;
+
+public class EnumParsingTests
+{
+    [U]
+    public void CanParseRegularEnum() => KnownEnums.Parse<RegularEnum>("first").Should().Be(RegularEnum.First);
+
+    [U]
+    public void CanParseEnumWithAttribute() => KnownEnums.Parse<EnumWithAttribute>("second_value").Should().Be(EnumWithAttribute.Second);
+
+    [U]
+    public void CanParseFlagsEnum() => KnownEnums.Parse<FlagsEnum>("first,third").Should().Be(FlagsEnum.First | FlagsEnum.Third);
+
+    [U]
+    public void CanParseFlagsEnumWithAttribute() => KnownEnums.Parse<FlagsEnumWithAttribute>("first_value,third_value").Should().Be(FlagsEnumWithAttribute.First | FlagsEnumWithAttribute.Third);
+
+private enum RegularEnum
+    {
+        First,
+        Second
+    }
+
+    private enum EnumWithAttribute
+    {
+        [EnumMember(Value = "first_value")]
+        First,
+        [EnumMember(Value = "second_value")]
+        Second
+    }
+
+    [Flags]
+    private enum FlagsEnum
+    {
+        First = 1 << 0,
+        Second = 1 << 1,
+        Third = 1 << 2
+    }
+
+    [Flags]
+    private enum FlagsEnumWithAttribute
+    {
+        [EnumMember(Value = "first_value")]
+        First = 1 << 0,
+        [EnumMember(Value = "second_value")]
+        Second = 1 << 1,
+        [EnumMember(Value = "third_value")]
+        Third = 1 << 2
+    }
+}