Fix AddSource operations on Roslyn 4.0.1

Author: Sergio0694

src/CommunityToolkit.Mvvm.SourceGenerators/CommunityToolkit.Mvvm.SourceGenerators.projitems

@@ -55,6 +55,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)Extensions\IncrementalGeneratorInitializationContextExtensions.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Extensions\IncrementalValuesProviderExtensions.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Extensions\ISymbolExtensions.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Extensions\SourceProductionContextExtensions.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Extensions\ITypeSymbolExtensions.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Extensions\MemberDeclarationSyntaxExtensions.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Extensions\SyntaxNodeExtensions.cs" />

src/CommunityToolkit.Mvvm.SourceGenerators/ComponentModel/ObservablePropertyGenerator.cs

@@ -4,7 +4,6 @@
 
 using System.Collections.Immutable;
 using System.Linq;
-using System.Text;
 using CommunityToolkit.Mvvm.SourceGenerators.ComponentModel.Models;
 using CommunityToolkit.Mvvm.SourceGenerators.Extensions;
 using CommunityToolkit.Mvvm.SourceGenerators.Helpers;
@@ -75,7 +74,7 @@ public void Initialize(IncrementalGeneratorInitializationContext context)
             // Insert all members into the same partial type declaration
             CompilationUnitSyntax compilationUnit = item.Hierarchy.GetCompilationUnit(memberDeclarations);
 
-            context.AddSource($"{item.Hierarchy.FilenameHint}.g.cs", compilationUnit.GetText(Encoding.UTF8));
+            context.AddSource($"{item.Hierarchy.FilenameHint}.g.cs", compilationUnit);
         });
 
         // Gather all property changing names
@@ -92,7 +91,7 @@ public void Initialize(IncrementalGeneratorInitializationContext context)
 
             if (compilationUnit is not null)
             {
-                context.AddSource("__KnownINotifyPropertyChangingArgs.g.cs", compilationUnit.GetText(Encoding.UTF8));
+                context.AddSource("__KnownINotifyPropertyChangingArgs.g.cs", compilationUnit);
             }
         });
 
@@ -110,7 +109,7 @@ public void Initialize(IncrementalGeneratorInitializationContext context)
 
             if (compilationUnit is not null)
             {
-                context.AddSource("__KnownINotifyPropertyChangedArgs.g.cs", compilationUnit.GetText(Encoding.UTF8));
+                context.AddSource("__KnownINotifyPropertyChangedArgs.g.cs", compilationUnit);
             }
         });
     }

src/CommunityToolkit.Mvvm.SourceGenerators/ComponentModel/ObservableValidatorValidateAllPropertiesGenerator.cs

@@ -3,7 +3,6 @@
 // See the LICENSE file in the project root for more information.
 
 using System.Linq;
-using System.Text;
 using CommunityToolkit.Mvvm.SourceGenerators.ComponentModel.Models;
 using CommunityToolkit.Mvvm.SourceGenerators.Extensions;
 using Microsoft.CodeAnalysis;
@@ -79,15 +78,15 @@ public void Initialize(IncrementalGeneratorInitializationContext context)
         {
             CompilationUnitSyntax compilationUnit = Execute.GetSyntax(item);
 
-            context.AddSource("__ObservableValidatorExtensions.g.cs", compilationUnit.GetText(Encoding.UTF8));
+            context.AddSource("__ObservableValidatorExtensions.g.cs", compilationUnit);
         });
 
         // Generate the class with all validation methods
         context.RegisterImplementationSourceOutput(validationInfo, static (context, item) =>
         {
             CompilationUnitSyntax compilationUnit = Execute.GetSyntax(item);
 
-            context.AddSource($"{item.FilenameHint}.g.cs", compilationUnit.GetText(Encoding.UTF8));
+            context.AddSource($"{item.FilenameHint}.g.cs", compilationUnit);
         });
     }
 }

src/CommunityToolkit.Mvvm.SourceGenerators/ComponentModel/TransitiveMembersGenerator.cs

@@ -5,7 +5,6 @@
 using System;
 using System.Collections.Immutable;
 using System.Linq;
-using System.Text;
 using CommunityToolkit.Mvvm.SourceGenerators.Extensions;
 using CommunityToolkit.Mvvm.SourceGenerators.Models;
 using Microsoft.CodeAnalysis;
@@ -108,7 +107,7 @@ public void Initialize(IncrementalGeneratorInitializationContext context)
             ImmutableArray<MemberDeclarationSyntax> updatedMemberDeclarations = Execute.AdjustMemberDeclarationNullabilityAnnotations(filteredMemberDeclarations, item.MetadataInfo.IsNullabilitySupported);
             CompilationUnitSyntax compilationUnit = item.Hierarchy.GetCompilationUnit(updatedMemberDeclarations, this.classDeclaration.BaseList);
 
-            context.AddSource($"{item.Hierarchy.FilenameHint}.g.cs", compilationUnit.GetText(Encoding.UTF8));
+            context.AddSource($"{item.Hierarchy.FilenameHint}.g.cs", compilationUnit);
         });
     }
 

src/CommunityToolkit.Mvvm.SourceGenerators/Extensions/SourceProductionContextExtensions.cs

@@ -0,0 +1,33 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.Text;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+
+namespace CommunityToolkit.Mvvm.SourceGenerators.Extensions;
+
+/// <summary>
+/// Extension methods for the <see cref="SourceProductionContext"/> type.
+/// </summary>
+internal static class SourceProductionContextExtensions
+{
+    /// <summary>
+    /// Adds a new source file to a target <see cref="SourceProductionContext"/> instance.
+    /// </summary>
+    /// <param name="context">The input <see cref="SourceProductionContext"/> instance to use.</param>
+    /// <param name="name">The name of the source file to add.</param>
+    /// <param name="compilationUnit">The <see cref="CompilationUnitSyntax"/> instance representing the syntax tree to add.</param>
+    public static void AddSource(this SourceProductionContext context, string name, CompilationUnitSyntax compilationUnit)
+    {
+#if !ROSLYN_4_3_1_OR_GREATER
+        // We're fine with the extra allocation in the few cases where adjusting the filename is necessary.
+        // This will only ever be done when code generation is executed again anyway, which is a slow path.
+        name = name.Replace('+', '_').Replace('`', '_');
+#endif
+        
+        // Add the UTF8 text for the input compilation unit
+        context.AddSource(name, compilationUnit.GetText(Encoding.UTF8));
+    }
+}

src/CommunityToolkit.Mvvm.SourceGenerators/Input/RelayCommandGenerator.cs

@@ -4,7 +4,6 @@
 
 using System.Collections.Immutable;
 using System.Linq;
-using System.Text;
 using CommunityToolkit.Mvvm.SourceGenerators.Extensions;
 using CommunityToolkit.Mvvm.SourceGenerators.Input.Models;
 using CommunityToolkit.Mvvm.SourceGenerators.Models;
@@ -61,7 +60,7 @@ public void Initialize(IncrementalGeneratorInitializationContext context)
             ImmutableArray<MemberDeclarationSyntax> memberDeclarations = Execute.GetSyntax(item.Info.Value);
             CompilationUnitSyntax compilationUnit = item.Hierarchy.GetCompilationUnit(memberDeclarations);
 
-            context.AddSource($"{item.Hierarchy.FilenameHint}.{item.Info.Value.MethodName}.g.cs", compilationUnit.GetText(Encoding.UTF8));
+            context.AddSource($"{item.Hierarchy.FilenameHint}.{item.Info.Value.MethodName}.g.cs", compilationUnit);
         });
     }
 }

src/CommunityToolkit.Mvvm.SourceGenerators/Messaging/IMessengerRegisterAllGenerator.cs

@@ -4,7 +4,6 @@
 
 using System.Collections.Immutable;
 using System.Linq;
-using System.Text;
 using CommunityToolkit.Mvvm.SourceGenerators.Extensions;
 using CommunityToolkit.Mvvm.SourceGenerators.Messaging.Models;
 using Microsoft.CodeAnalysis;
@@ -84,15 +83,15 @@ public void Initialize(IncrementalGeneratorInitializationContext context)
         {
             CompilationUnitSyntax compilationUnit = Execute.GetSyntax(item);
 
-            context.AddSource("__IMessengerExtensions.g.cs", compilationUnit.GetText(Encoding.UTF8));
+            context.AddSource("__IMessengerExtensions.g.cs", compilationUnit);
         });
 
         // Generate the class with all registration methods
         context.RegisterImplementationSourceOutput(recipientInfo, static (context, item) =>
         {
             CompilationUnitSyntax compilationUnit = Execute.GetSyntax(item);
 
-            context.AddSource($"{item.FilenameHint}.g.cs", compilationUnit.GetText(Encoding.UTF8));
+            context.AddSource($"{item.FilenameHint}.g.cs", compilationUnit);
         });
     }
 }