perf: Add NativeAOT Support

.github/workflows/aot-compatibility.yml

@@ -0,0 +1,97 @@
+name: AOT Compatibility
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+  merge_group:
+  workflow_dispatch:
+
+jobs:
+  aot-compatibility:
+    name: AOT Test (${{ matrix.os }}, ${{ matrix.arch }})
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          # Linux x64
+          - os: ubuntu-latest
+            arch: x64
+            runtime: linux-x64
+          # Linux ARM64
+          - os: ubuntu-24.04-arm
+            arch: arm64
+            runtime: linux-arm64
+          # Windows x64
+          - os: windows-latest
+            arch: x64
+            runtime: win-x64
+          # Windows ARM64
+          - os: windows-11-arm
+            arch: arm64
+            runtime: win-arm64
+          # macOS x64
+          - os: macos-13
+            arch: x64
+            runtime: osx-x64
+          # macOS ARM64 (Apple Silicon)
+          - os: macos-latest
+            arch: arm64
+            runtime: osx-arm64
+
+    runs-on: ${{ matrix.os }}
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4
+        with:
+          fetch-depth: 0
+          submodules: recursive
+
+      - name: Setup .NET SDK
+        uses: actions/setup-dotnet@67a3573c9a986a3f9c594539f4ab511d57bb3ce9 # v4
+        env:
+          NUGET_AUTH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          global-json-file: global.json
+          source-url: https://nuget.pkg.github.com/open-feature/index.json
+
+      - name: Cache NuGet packages
+        uses: actions/cache@5a3ec84eff668545956fd18022155c47e93e2684 # v4.2.3
+        with:
+          path: ~/.nuget/packages
+          key: ${{ runner.os }}-${{ matrix.arch }}-nuget-${{ hashFiles('**/*.csproj') }}
+          restore-keys: |
+            ${{ runner.os }}-${{ matrix.arch }}-nuget-
+            ${{ runner.os }}-nuget-
+
+      - name: Restore dependencies
+        shell: pwsh
+        run: dotnet restore
+
+      - name: Build solution
+        shell: pwsh
+        run: dotnet build -c Release --no-restore
+
+      - name: Test AOT compatibility project build
+        shell: pwsh
+        run: dotnet build test/OpenFeature.AotCompatibility/OpenFeature.AotCompatibility.csproj -c Release --no-restore
+
+      - name: Publish AOT compatibility test (cross-platform)
+        shell: pwsh
+        run: |
+          dotnet publish test/OpenFeature.AotCompatibility/OpenFeature.AotCompatibility.csproj `
+            -c Release `
+            -r ${{ matrix.runtime }} `
+            -o ./aot-output
+
+      - name: Run AOT compatibility test
+        shell: pwsh
+        run: |
+          if ("${{ runner.os }}" -eq "Windows") {
+            ./aot-output/OpenFeature.AotCompatibility.exe
+          } else {
+            chmod +x ./aot-output/OpenFeature.AotCompatibility
+            ./aot-output/OpenFeature.AotCompatibility
+          }

Directory.Packages.props

@@ -36,6 +36,8 @@
     <PackageVersion Include="coverlet.msbuild" Version="6.0.4" />
     <PackageVersion Include="GitHubActionsTestLogger" Version="2.4.1" />
     <PackageVersion Include="Microsoft.Extensions.Diagnostics.Testing" Version="9.3.0" />
+    <PackageVersion Include="Microsoft.Extensions.Logging.Console" Version="$(MicrosoftExtensionsVersion)" />
+    <PackageVersion Include="Microsoft.Extensions.Hosting" Version="$(MicrosoftExtensionsVersion)" />
     <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="17.14.1" />
     <PackageVersion Include="NSubstitute" Version="5.3.0" />
     <PackageVersion Include="OpenTelemetry" Version="1.12.0" />

OpenFeature.slnx

@@ -53,7 +53,7 @@
   <Folder Name="/src/">
     <Project Path="src/OpenFeature.DependencyInjection/OpenFeature.DependencyInjection.csproj" />
     <Project Path="src/OpenFeature.Hosting/OpenFeature.Hosting.csproj" />
-    <Project Path="src/OpenFeature.Providers.MultiProvider/OpenFeature.Providers.MultiProvider.csproj" Type="Classic C#" />
+    <Project Path="src/OpenFeature.Providers.MultiProvider/OpenFeature.Providers.MultiProvider.csproj" />
     <Project Path="src/OpenFeature/OpenFeature.csproj" />
     <File Path="src/Directory.Build.props" />
     <File Path="src/Directory.Build.targets" />
@@ -64,7 +64,8 @@
     <Project Path="test/OpenFeature.E2ETests/OpenFeature.E2ETests.csproj" />
     <Project Path="test/OpenFeature.IntegrationTests/OpenFeature.IntegrationTests.csproj" />
     <Project Path="test/OpenFeature.Tests/OpenFeature.Tests.csproj" />
-    <Project Path="test\OpenFeature.Providers.MultiProvider.Tests\OpenFeature.Providers.MultiProvider.Tests.csproj" Type="Classic C#" />
+    <Project Path="test/OpenFeature.AotCompatibility\OpenFeature.AotCompatibility.csproj" />
+    <Project Path="test\OpenFeature.Providers.MultiProvider.Tests\OpenFeature.Providers.MultiProvider.Tests.csproj" />
     <File Path="test/Directory.Build.props" />
   </Folder>
-</Solution>
+</Solution>

build/Common.prod.props

@@ -1,5 +1,5 @@
 <Project>
-  <Import Project=".\Common.props" />
+  <Import Project=".\Common.props"/>
 
   <PropertyGroup>
     <ContinuousIntegrationBuild Condition="'$(CI)' == 'true'">true</ContinuousIntegrationBuild>
@@ -24,8 +24,13 @@
     <FileVersion>$(VersionNumber)</FileVersion>
   </PropertyGroup>
 
+  <!-- AOT and Trimming Support -->
+  <PropertyGroup Condition="'$(TargetFramework)' == 'net8.0' or '$(TargetFramework)' == 'net9.0'">
+    <IsAotCompatible>true</IsAotCompatible>
+  </PropertyGroup>
+
   <ItemGroup>
-    <None Include="$(MSBuildThisFileDirectory)openfeature-icon.png" Pack="true" PackagePath="\" />
+    <None Include="$(MSBuildThisFileDirectory)openfeature-icon.png" Pack="true" PackagePath="\"/>
   </ItemGroup>
 
 </Project>

src/OpenFeature.Providers.MultiProvider/OpenFeature.Providers.MultiProvider.csproj

@@ -9,6 +9,7 @@
   <ItemGroup>
     <InternalsVisibleTo Include="DynamicProxyGenAssembly2" />
     <InternalsVisibleTo Include="OpenFeature.Providers.MultiProvider.Tests" />
+    <InternalsVisibleTo Include="OpenFeature.AotCompatibility" />
     <None Include="README.md" Pack="true" PackagePath="/" />
   </ItemGroup>
 

src/OpenFeature/Constant/ErrorType.cs

@@ -1,5 +1,3 @@
-using System.ComponentModel;
-
 namespace OpenFeature.Constant;
 
 /// <summary>
@@ -16,40 +14,40 @@ public enum ErrorType
     /// <summary>
     /// Provider has yet been initialized
     /// </summary>
-    [Description("PROVIDER_NOT_READY")] ProviderNotReady,
+    ProviderNotReady,
 
     /// <summary>
     /// Provider was unable to find the flag
     /// </summary>
-    [Description("FLAG_NOT_FOUND")] FlagNotFound,
+    FlagNotFound,
 
     /// <summary>
     /// Provider failed to parse the flag response
     /// </summary>
-    [Description("PARSE_ERROR")] ParseError,
+    ParseError,
 
     /// <summary>
     /// Request type does not match the expected type
     /// </summary>
-    [Description("TYPE_MISMATCH")] TypeMismatch,
+    TypeMismatch,
 
     /// <summary>
     /// Abnormal execution of the provider
     /// </summary>
-    [Description("GENERAL")] General,
+    General,
 
     /// <summary>
     /// Context does not satisfy provider requirements.
     /// </summary>
-    [Description("INVALID_CONTEXT")] InvalidContext,
+    InvalidContext,
 
     /// <summary>
     /// Context does not contain a targeting key and the provider requires one.
     /// </summary>
-    [Description("TARGETING_KEY_MISSING")] TargetingKeyMissing,
+    TargetingKeyMissing,
 
     /// <summary>
     /// The provider has entered an irrecoverable error state.
     /// </summary>
-    [Description("PROVIDER_FATAL")] ProviderFatal,
+    ProviderFatal,
 }

src/OpenFeature/Extension/EnumExtensions.cs

@@ -1,13 +1,32 @@
-using System.ComponentModel;
+using OpenFeature.Constant;
 
 namespace OpenFeature.Extension;
 
 internal static class EnumExtensions
 {
+    /// <summary>
+    /// Gets the description of an enum value without using reflection.
+    /// This is AOT-compatible and only supports specific known enum types.
+    /// </summary>
+    /// <param name="value">The enum value to get the description for</param>
+    /// <returns>The description string or the enum value as string if no description is available</returns>
     public static string GetDescription(this Enum value)
     {
-        var field = value.GetType().GetField(value.ToString());
-        var attribute = field?.GetCustomAttributes(typeof(DescriptionAttribute), false).FirstOrDefault() as DescriptionAttribute;
-        return attribute?.Description ?? value.ToString();
+        return value switch
+        {
+            // ErrorType descriptions
+            ErrorType.None => "NONE",
+            ErrorType.ProviderNotReady => "PROVIDER_NOT_READY",
+            ErrorType.FlagNotFound => "FLAG_NOT_FOUND",
+            ErrorType.ParseError => "PARSE_ERROR",
+            ErrorType.TypeMismatch => "TYPE_MISMATCH",
+            ErrorType.General => "GENERAL",
+            ErrorType.InvalidContext => "INVALID_CONTEXT",
+            ErrorType.TargetingKeyMissing => "TARGETING_KEY_MISSING",
+            ErrorType.ProviderFatal => "PROVIDER_FATAL",
+
+            // Fallback for any other enum types
+            _ => value.ToString()
+        };
     }
 }

src/OpenFeature/Model/ValueJsonConverter.cs

@@ -5,7 +5,9 @@
 namespace OpenFeature.Model;
 
 /// <summary>
-/// A <see cref="JsonConverter{T}"/> for <see cref="Value"/> for Json serialization
+/// A <see cref="JsonConverter{T}"/> for <see cref="Value"/> for Json serialization.
+/// This converter is AOT-compatible as it uses manual JSON reading/writing 
+/// instead of reflection-based serialization.
 /// </summary>
 public sealed class ValueJsonConverter : JsonConverter<Value>
 {

src/OpenFeature/OpenFeature.csproj

@@ -21,7 +21,8 @@
     <InternalsVisibleTo Include="OpenFeature.E2ETests" />
     <InternalsVisibleTo Include="OpenFeature.DependencyInjection" />
     <InternalsVisibleTo Include="OpenFeature.Providers.MultiProvider.Tests" />
+    <InternalsVisibleTo Include="OpenFeature.AotCompatibility" />
     <None Include="../../README.md" Pack="true" PackagePath="/" />
   </ItemGroup>
 
-</Project>
+</Project>

src/OpenFeature/Serialization/OpenFeatureJsonSerializerContext.cs

@@ -0,0 +1,28 @@
+using System.Collections.Immutable;
+using System.Text.Json.Serialization;
+using OpenFeature.Model;
+
+namespace OpenFeature.Serialization;
+
+/// <summary>
+/// JSON serializer context for AOT compilation support.
+/// This ensures that all necessary types are pre-compiled for JSON serialization
+/// when using NativeAOT.
+/// </summary>
+[JsonSerializable(typeof(Value))]
+[JsonSerializable(typeof(Structure))]
+[JsonSerializable(typeof(EvaluationContext))]
+[JsonSerializable(typeof(Dictionary<string, Value>))]
+[JsonSerializable(typeof(ImmutableDictionary<string, Value>))]
+[JsonSerializable(typeof(List<Value>))]
+[JsonSerializable(typeof(ImmutableList<Value>))]
+[JsonSerializable(typeof(bool))]
+[JsonSerializable(typeof(string))]
+[JsonSerializable(typeof(int))]
+[JsonSerializable(typeof(double))]
+[JsonSerializable(typeof(DateTime))]
+[JsonSourceGenerationOptions(
+    WriteIndented = false,
+    PropertyNamingPolicy = JsonKnownNamingPolicy.CamelCase,
+    DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull)]
+public partial class OpenFeatureJsonSerializerContext : JsonSerializerContext;

test/OpenFeature.AotCompatibility/OpenFeature.AotCompatibility.csproj

@@ -0,0 +1,34 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+    <PropertyGroup>
+        <TargetFramework>net9.0</TargetFramework>
+        <OutputType>Exe</OutputType>
+        <Nullable>enable</Nullable>
+        <ImplicitUsings>enable</ImplicitUsings>
+
+        <!-- NativeAOT Configuration -->
+        <PublishAot>true</PublishAot>
+        <IsAotCompatible>true</IsAotCompatible>
+        <InvariantGlobalization>true</InvariantGlobalization>
+        <TrimMode>full</TrimMode>
+        <IlcOptimizationPreference>Size</IlcOptimizationPreference>
+
+        <!-- Suppress vulnerable package warnings for this test project -->
+        <TreatWarningsAsErrors>false</TreatWarningsAsErrors>
+        <WarningsNotAsErrors>NU1903</WarningsNotAsErrors>
+        <RootNamespace>OpenFeature.AotCompatibility</RootNamespace>
+    </PropertyGroup>
+
+    <ItemGroup>
+        <ProjectReference Include="..\..\src\OpenFeature\OpenFeature.csproj" />
+        <ProjectReference Include="..\..\src\OpenFeature.DependencyInjection\OpenFeature.DependencyInjection.csproj" />
+        <ProjectReference Include="..\..\src\OpenFeature.Providers.MultiProvider\OpenFeature.Providers.MultiProvider.csproj" />
+    </ItemGroup>
+
+    <ItemGroup>
+        <PackageReference Include="Microsoft.Extensions.DependencyInjection" />
+        <PackageReference Include="Microsoft.Extensions.Hosting" />
+        <PackageReference Include="Microsoft.Extensions.Logging.Console" />
+    </ItemGroup>
+
+</Project>