CodeGenerator: clean up attribute handling and remove obsolete custom-attribute build properties

[Youssef1313]

Related to #9664, but doesn't fix it.

Microsoft Reviewers: Open in CodeFlow

[Copilot]

Pull request overview

This pull request simplifies the Orleans source generator by removing support for configurable attribute lists and hardcoding the well-known Orleans attributes. The changes convert CodeGeneratorOptions from having mutable List<string> properties to const and static readonly fields, and update LibraryTypes to store single INamedTypeSymbol references instead of arrays.

Changes:

• Removed MSBuild property reading for customizable attribute lists (ImmutableAttributes, IdAttributes, AliasAttributes, GenerateSerializerAttributes) from OrleansSourceGenerator.cs
• Converted CodeGeneratorOptions from mutable Lists to const/readonly values
• Changed LibraryTypes properties from arrays to single symbols (IdAttributeTypes → IdAttributeType, ImmutableAttributes → ImmutableAttribute, GenerateSerializerAttributes → GenerateSerializerAttribute)
• Updated method calls from HasAnyAttribute() to HasAttribute() in modified files
• Removed dead code (unused referencedAssemblies variable, unused GenerateSerializerAttributes property)
• Optimized attribute retrieval by moving it outside the symbol loop

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
src/Orleans.CodeGenerator/OrleansSourceGenerator.cs	Removed code that reads customizable attribute MSBuild properties; simplified to only read GenerateFieldIds and GenerateCompatibilityInvokers options
src/Orleans.CodeGenerator/CodeGenerator.cs	Changed CodeGeneratorOptions from mutable Lists to const/readonly values; updated calls to use singular attribute properties; removed dead code
src/Orleans.CodeGenerator/LibraryTypes.cs	Converted plural attribute property arrays to singular properties; removed unused GenerateSerializerAttributes property
src/Orleans.CodeGenerator/SyntaxGeneration/FSharpUtils.cs	Updated calls from HasAnyAttribute to HasAttribute for ImmutableAttribute

Comments suppressed due to low confidence (1)

src/Orleans.CodeGenerator/OrleansSourceGenerator.cs:58

• The OrleansSourceGenerator.cs removed code that reads MSBuild properties (orleans_immutableattributes, orleans_idattributes, orleans_aliasattributes, orleans_generateserializerattributes), but the build props file at src/Orleans.CodeGenerator/build/Microsoft.Orleans.CodeGenerator.props still defines these properties.

If these properties are no longer supported, they should be removed from the build props file to avoid confusion. If they're kept for backward compatibility, consider adding comments explaining they're no longer used.

                var options = new CodeGeneratorOptions();

                if (context.AnalyzerConfigOptions.GlobalOptions.TryGetValue("build_property.orleans_generatefieldids", out var generateFieldIds) && generateFieldIds is { Length: > 0 })
                {
                    if (Enum.TryParse(generateFieldIds, out GenerateFieldIds fieldIdOption))
                    {
                        options.GenerateFieldIds = fieldIdOption;
                    }
                }

                if (context.AnalyzerConfigOptions.GlobalOptions.TryGetValue("build_property.orleansgeneratecompatibilityinvokers", out var generateCompatInvokersValue)
                    && bool.TryParse(generateCompatInvokersValue, out var genCompatInvokers))
                {
                    options.GenerateCompatibilityInvokers = genCompatInvokers;
                }

                var codeGenerator = new CodeGenerator(context.Compilation, options);
                var syntax = codeGenerator.GenerateCode(context.CancellationToken);
                var sourceString = syntax.NormalizeWhitespace().ToFullString();