Kiota: Replace PowerShell script with inline MSBuild task for improved performance

Author: bkoelman

src/JsonApiDotNetCore.OpenApi.Client.Kiota/Build/JsonApiDotNetCore.OpenApi.Client.Kiota.targets

@@ -1,5 +1,49 @@
 <!-- Loosely based on https://github.com/kimbell/Kiota.Testing, related to https://github.com/microsoft/kiota/issues/3005 -->
 <Project>
+  <UsingTask TaskName="KiotaPatchGeneratedCodeFiles" TaskFactory="RoslynCodeTaskFactory" AssemblyFile="$(MSBuildToolsPath)\Microsoft.Build.Tasks.Core.dll">
+    <ParameterGroup>
+      <StartDirectory ParameterType="System.String" Required="true" />
+    </ParameterGroup>
+    <Task>
+      <Code Type="Class" Language="cs">
+        <![CDATA[
+        using System;
+        using System.IO;
+        using System.Text.RegularExpressions;
+        using Microsoft.Build.Framework;
+        using Microsoft.Build.Utilities;
+
+        public sealed class KiotaPatchGeneratedCodeFiles : Task
+        {
+            private static readonly Regex HeaderRegex = new(@"// <auto-generated/>(?:\r\n|\n|\r)(#pragma|using)", RegexOptions.Singleline | RegexOptions.Compiled);
+            private static readonly Regex NullableRegex = new(@"(?s)#if NETSTANDARD2_1_OR_GREATER .*?(?:\r\n|\n|\r)#nullable enable(?:\r\n|\n|\r)(?<ifBody>.*?)(?:\r\n|\n|\r)#nullable restore(?:\r\n|\n|\r)#else(?:\r\n|\n|\r)(?<elseBody>.*?)(?:\r\n|\n|\r)#endif", RegexOptions.Singleline | RegexOptions.Compiled);
+            private static readonly Regex LineBreaksRegex = new(@"}(?:\r\n|\n|\r)(?<lineIndent>[ ]+/// <summary>)", RegexOptions.Singleline | RegexOptions.Compiled);
+
+            public string StartDirectory { get; set; }
+
+            public override bool Execute()
+            {
+                string absoluteStartDirectory = Path.GetFullPath(StartDirectory);
+                Log.LogMessage(MessageImportance.High, $"Patching kiota output files in {absoluteStartDirectory}");
+
+                foreach (string path in Directory.GetFiles(absoluteStartDirectory, "*.cs", SearchOption.AllDirectories))
+                {
+                    string content = File.ReadAllText(path);
+                    content = HeaderRegex.Replace(content, $"// <auto-generated/>{Environment.NewLine}#nullable enable{Environment.NewLine}#pragma warning disable CS8625{Environment.NewLine}$1");
+                    content = NullableRegex.Replace(content, "$1");
+                    content = LineBreaksRegex.Replace(content, $"}}{Environment.NewLine}{Environment.NewLine}$1");
+
+                    File.WriteAllText(path, content);
+                    Log.LogMessage(MessageImportance.Normal, $"Patched file: {path}");
+                }
+
+                return true;
+            }
+        }
+        ]]>
+      </Code>
+    </Task>
+  </UsingTask>
 
   <!-- Restore local tools -->
   <Target Name="_KiotaRestoreTools" Condition="'$(KiotaAutoRestoreTools)' == 'true'">
@@ -140,11 +184,6 @@
     <Exec Command="$(_KiotaCommand) %(KiotaReference.Arguments)" EnvironmentVariables="KIOTA_TUTORIAL_ENABLED=false;KIOTA_OFFLINE_ENABLED=true" />
 
     <!-- Post-process output files -->
-    <Message Importance="High" Condition="'$(KiotaPatchOutput)' == 'true'" Text="Patching kiota output files in %(KiotaReference.OutputPath)" />
-    <Exec Condition="'$(KiotaPatchOutput)' == 'true'" ConsoleToMSBuild="true"
-      Command="pwsh $(MSBuildThisFileDirectory)kiota-patch-generated-code.ps1 %(KiotaReference.OutputPath)">
-      <Output TaskParameter="ConsoleOutput" ItemName="OutputLinesOfScript" />
-    </Exec>
-    <Error Condition="'@(OutputLinesOfScript)' != ''" Text="@(OutputLinesOfScript, '%0a')" />
+    <KiotaPatchGeneratedCodeFiles StartDirectory="%(KiotaReference.OutputPath)" />
   </Target>
 </Project>

src/JsonApiDotNetCore.OpenApi.Client.Kiota/Build/kiota-patch-generated-code.ps1

@@ -29,7 +29,6 @@
     <None Include="..\..\PackageReadme.md" Visible="false" Pack="True" PackagePath="" />
     <None Include="Build\*.props" Pack="True" PackagePath="build" />
     <None Include="Build\*.targets" Pack="True" PackagePath="build" />
-    <None Include="Build\*.ps1" Pack="True" PackagePath="build" />
   </ItemGroup>
 
   <ItemGroup>