Replace PSVersion source generator with incremental one (#23815)

PowerShell.sln

@@ -31,6 +31,8 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "powershell-unix", "src\powe
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "xUnit.tests", "test\xUnit\xUnit.tests.csproj", "{08704934-9764-48CE-86DB-BCF0A1CF7899}"
 EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "PSVersionInfoGenerator", "src\System.Management.Automation\SourceGenerators\PSVersionInfoGenerator\PSVersionInfoGenerator.csproj", "{B22424E8-0516-4FC3-A9CB-D84D15EF0589}"
+EndProject
 # Configuration mapping comment
 # All global configurations must be mapped to project configurations
 #

src/System.Management.Automation/SourceGenerators/PSVersionInfoGenerator/PSVersionInfoGenerator.cs

@@ -11,40 +11,70 @@ namespace SMA
     /// Source Code Generator to create partial PSVersionInfo class.
     /// </summary>
     [Generator]
-    public class PSVersionInfoGenerator : ISourceGenerator
+    public class PSVersionInfoGenerator : IIncrementalGenerator
     {
-        /// <summary>
-        /// Generate output PSVersionInfo.g.cs file.
-        /// This allows to directly get ProductVersion and others without reflection.
-        /// </summary>
-        /// <param name="context">Generator execution context.</param>
-        public void Execute(GeneratorExecutionContext context)
-        {
-            var result = CreatePSVersionInfoPartialClass(context);
-
-            // We must use specific file name suffix (*.g.cs,*.g, *.i.cs, *.generated.cs, *.designer.cs)
-            // so that Roslyn analyzers skip the file.
-            context.AddSource("PSVersionInfo.g.cs", result);
-        }
-
         /// <summary>
         /// Not used.
         /// </summary>
         /// <param name="context">Generator initialization context.</param>
-        public void Initialize(GeneratorInitializationContext context)
+        public void Initialize(IncrementalGeneratorInitializationContext context)
         {
-            // No initialization required for this one.
+            IncrementalValueProvider<BuildOptions> buildOptionsProvider = context.AnalyzerConfigOptionsProvider
+                .Select(static (provider, _) =>
+                {
+                    provider.GlobalOptions.TryGetValue("build_property.ProductVersion", out var productVersion);
+                    provider.GlobalOptions.TryGetValue("build_property.PSCoreBuildVersion", out var mainVersion);
+                    provider.GlobalOptions.TryGetValue("build_property.PowerShellVersion", out var gitDescribe);
+                    provider.GlobalOptions.TryGetValue("build_property.ReleaseTag", out var releaseTag);
+
+                    BuildOptions options = new()
+                    {
+                        ProductVersion = productVersion ?? string.Empty,
+                        MainVersion = mainVersion ?? string.Empty,
+                        GitDescribe = gitDescribe ?? string.Empty,
+                        ReleaseTag = releaseTag ?? string.Empty
+                    };
+
+                    return options;
+                });
+
+            context.RegisterSourceOutput(
+                buildOptionsProvider,
+                static (context, buildOptions) =>
+                {
+                    string gitCommitId = string.IsNullOrEmpty(buildOptions.ReleaseTag) ? buildOptions.GitDescribe : buildOptions.ReleaseTag;
+                    if (gitCommitId.StartsWith("v"))
+                    {
+                        gitCommitId = gitCommitId.Substring(1);
+                    }
+
+                    var versions = ParsePSVersion(buildOptions.MainVersion);
+                    string result = string.Format(
+                        CultureInfo.InvariantCulture,
+                        SourceTemplate,
+                        buildOptions.ProductVersion,
+                        gitCommitId,
+                        versions.major,
+                        versions.minor,
+                        versions.patch,
+                        versions.preReleaseLabel);
+
+                    // We must use specific file name suffix (*.g.cs,*.g, *.i.cs, *.generated.cs, *.designer.cs)
+                    // so that Roslyn analyzers skip the file.
+                    context.AddSource("PSVersionInfo.g.cs", result);
+                });
         }
 
-        /// <summary>
+        private struct BuildOptions
-        /// Generate source code for the partial PSVersionInfo class.
-        /// </summary>
-        /// <param name="context">Generator execution context.</param>
-        /// <returns>A string with partial PSVersionInfo class.</returns>
-        private static string CreatePSVersionInfoPartialClass(GeneratorExecutionContext context)
         {
-            // We must put "<auto-generated" on first line so that Roslyng analyzers skip the file.
+            public string ProductVersion;
-            const string SourceTemplate = @"// <auto-generated>
+            public string MainVersion;
+            public string GitDescribe;
+            public string ReleaseTag;
+        }
+
+        // We must put "<auto-generated" on first line so that Roslyng analyzers skip the file.
+        private const string SourceTemplate = @"// <auto-generated>
 // This file is auto-generated by PSVersionInfoGenerator.
 // </auto-generated>
 
@@ -81,30 +111,6 @@ namespace System.Management.Automation
     }}
 }}";
 
-            context.AnalyzerConfigOptions.GlobalOptions.TryGetValue("build_property.ProductVersion", out var productVersion);
-            context.AnalyzerConfigOptions.GlobalOptions.TryGetValue("build_property.PSCoreBuildVersion", out var mainVersion);
-            context.AnalyzerConfigOptions.GlobalOptions.TryGetValue("build_property.PowerShellVersion", out var gitDescribe);
-            context.AnalyzerConfigOptions.GlobalOptions.TryGetValue("build_property.ReleaseTag", out var releaseTag);
-
-            string gitCommitId = string.IsNullOrEmpty(releaseTag) ? gitDescribe : releaseTag;
-            if (gitCommitId.StartsWith("v"))
-            {
-                gitCommitId = gitCommitId.Substring(1);
-            }
-
-            var result = ParsePSVersion(mainVersion);
-
-            return string.Format(
-                CultureInfo.InvariantCulture,
-                SourceTemplate,
-                productVersion,
-                gitCommitId,
-                result.major,
-                result.minor,
-                result.patch,
-                result.preReleaseLabel);
-        }
-
         private static (int major, int minor, int patch, string preReleaseLabel) ParsePSVersion(string mainVersion)
         {
             // We only handle the pre-defined PSVersion format here, e.g. 7.x.x or 7.x.x-preview.x

src/System.Management.Automation/SourceGenerators/PSVersionInfoGenerator/PSVersionInfoGenerator.csproj

@@ -10,7 +10,7 @@
     <LangVersion>11.0</LangVersion>
     <SuppressNETCoreSdkPreviewMessage>true</SuppressNETCoreSdkPreviewMessage>
     <EnforceExtendedAnalyzerRules>true</EnforceExtendedAnalyzerRules>
-    <NoWarn>RS1035</NoWarn>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>