Fix explicit interface method emission and diagnostics (#2017)

* Fix explicit interface method emission and diagnostics

Improves handling of explicit interface implementations in the source generator, ensuring that methods explicitly implemented from base interfaces are not redundantly emitted and that diagnostics are not incorrectly reported. Updates method model and emitter logic to track explicitness, normalizes method lookup keys, and adds polyfills for Index/Range for legacy targets. Updates tests and snapshots to reflect correct code generation.

* Fix typo in workflow input and add CODECOV_TOKEN secret

Corrects 'installWorkflows' to 'installWorkloads' in both ci-build and release workflows. Also adds the CODECOV_TOKEN secret to the ci-build workflow for code coverage reporting.

* Remove installWorkloads parameter from workflows

The installWorkloads parameter was removed from both ci-build.yml and release.yml GitHub Actions workflows, simplifying the configuration.

Author: ChrisPulman

.github/workflows/ci-build.yml

@@ -15,4 +15,5 @@ jobs:
     with:
       productNamespacePrefix: "Refit"
       srcFolder: "./"
-      installWorkflows: true
+    secrets:
+      CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}

.github/workflows/release.yml

@@ -14,7 +14,6 @@ jobs:
       configuration: Release
       productNamespacePrefix: "Refit"
       srcFolder: "./"
-      installWorkflows: false
     secrets:
       SIGN_ACCOUNT_NAME: ${{ secrets.SIGN_ACCOUNT_NAME }}
       SIGN_PROFILE_NAME: ${{ secrets.SIGN_PROFILE_NAME }}

Directory.Build.props

@@ -23,7 +23,9 @@
     <PublishRepositoryUrl>true</PublishRepositoryUrl>
     <AssemblyOriginatorKeyFile>$(MSBuildThisFileDirectory)buildtask.snk</AssemblyOriginatorKeyFile>
     <!--<SignAssembly>true</SignAssembly>-->
-    <RefitTargets>net462;netstandard2.0;net8.0;net9.0</RefitTargets>
+    <RefitTargets Condition="$([MSBuild]::IsOsPlatform('Windows'))">net462</RefitTargets>
+    <RefitTestTargets>net8.0;net9.0;net10.0</RefitTestTargets>
+    <RefitTargets>$(RefitTargets);netstandard2.0;$(RefitTestTargets)</RefitTargets>
     <NoWarn>IDE0040;CA1054;CA1510</NoWarn>
   </PropertyGroup>
 

InterfaceStubGenerator.Shared/Emitter.cs

@@ -195,7 +195,8 @@ UniqueNameBuilder uniqueNames
             ),
         };
 
-        WriteMethodOpening(source, methodModel, !isTopLevel, isAsync);
+        var isExplicit = methodModel.IsExplicitInterface || !isTopLevel;
+        WriteMethodOpening(source, methodModel, isExplicit, isExplicit, isAsync);
 
         // Build the list of args for the array
         var argArray = methodModel
@@ -219,10 +220,18 @@ UniqueNameBuilder uniqueNames
                 ? $", new global::System.Type[] {{ {string.Join(", ", genericArray)} }}"
                 : string.Empty;
 
+        // Normalize method lookup key: strip explicit interface prefix if present (e.g. IFoo.Bar -> Bar)
+        var lookupName = methodModel.Name;
+        var lastDotIndex = lookupName.LastIndexOf('.');
+        if (lastDotIndex >= 0 && lastDotIndex < lookupName.Length - 1)
+        {
+            lookupName = lookupName.Substring(lastDotIndex + 1);
+        }
+
         source.WriteLine(
             $"""
             var ______arguments = {argumentsArrayString};
-            var ______func = requestBuilder.BuildRestResultFuncForMethod("{methodModel.Name}", {parameterTypesExpression}{genericString} );
+            var ______func = requestBuilder.BuildRestResultFuncForMethod("{lookupName}", {parameterTypesExpression}{genericString} );
 
             {@return}({returnType})______func(this.Client, ______arguments){configureAwait};
             """
@@ -233,7 +242,8 @@ UniqueNameBuilder uniqueNames
 
     private static void WriteNonRefitMethod(SourceWriter source, MethodModel methodModel)
     {
-        WriteMethodOpening(source, methodModel, true);
+        var isExplicit = methodModel.IsExplicitInterface;
+        WriteMethodOpening(source, methodModel, isExplicit, isExplicit);
 
         source.WriteLine(
             @"throw new global::System.NotImplementedException(""Either this method has no Refit HTTP method attribute or you've used something other than a string literal for the 'path' argument."");"
@@ -242,9 +252,6 @@ private static void WriteNonRefitMethod(SourceWriter source, MethodModel methodM
         WriteMethodClosing(source);
     }
 
-    // TODO: This assumes that the Dispose method is a void that takes no parameters.
-    // The previous version did not.
-    // Does the bool overload cause an issue here.
     private static void WriteDisposableMethod(SourceWriter source)
     {
         source.WriteLine(
@@ -293,6 +300,7 @@ UniqueNameBuilder uniqueNames
     private static void WriteMethodOpening(
         SourceWriter source,
         MethodModel methodModel,
+        bool isDerivedExplicitImpl,
         bool isExplicitInterface,
         bool isAsync = false
     )
@@ -308,7 +316,12 @@ private static void WriteMethodOpening(
 
         if (isExplicitInterface)
         {
-            builder.Append(@$"{methodModel.ContainingType}.");
+            var ct = methodModel.ContainingType;
+            if (!ct.StartsWith("global::"))
+            {
+                ct = "global::" + ct;
+            }
+            builder.Append(@$"{ct}.");
         }
         builder.Append(@$"{methodModel.DeclaredMethod}(");
 
@@ -318,7 +331,6 @@ private static void WriteMethodOpening(
             foreach (var param in methodModel.Parameters)
             {
                 var annotation = param.Annotation;
-
                 list.Add($@"{param.Type}{(annotation ? '?' : string.Empty)} @{param.MetadataName}");
             }
 
@@ -330,7 +342,7 @@ private static void WriteMethodOpening(
         source.WriteLine();
         source.WriteLine(builder.ToString());
         source.Indentation++;
-        GenerateConstraints(source, methodModel.Constraints, isExplicitInterface);
+        GenerateConstraints(source, methodModel.Constraints, isDerivedExplicitImpl || isExplicitInterface);
         source.Indentation--;
         source.WriteLine("{");
         source.Indentation++;

InterfaceStubGenerator.Shared/ImmutableEquatableArray.cs

@@ -64,7 +64,7 @@ static int Combine(int h1, int h2)
 
     IEnumerator IEnumerable.GetEnumerator() => _values.GetEnumerator();
 
-    public struct Enumerator
+    public record struct Enumerator
     {
         private readonly T[] _values;
         private int _index;

InterfaceStubGenerator.Shared/InterfaceStubGenerator.Shared.projitems

@@ -23,6 +23,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)Models\TypeConstraint.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Models\WellKnownTypes.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Parser.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Polyfills\IndexRange.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)SourceWriter.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)UniqueNameBuilder.cs" />
   </ItemGroup>

InterfaceStubGenerator.Shared/InterfaceStubGenerator.cs

@@ -10,13 +10,8 @@
 
 namespace Refit.Generator
 {
-    // * Search for all Interfaces, find the method definitions
-    //   and make sure there's at least one Refit attribute on one
-    // * Generate the data we need for the template based on interface method
-    //   defn's
-
     /// <summary>
-    /// InterfaceStubGeneratorV2.
+    /// InterfaceStubGenerator.
     /// </summary>
     [Generator]
 #if ROSLYN_4
@@ -28,7 +23,6 @@ public class InterfaceStubGenerator : ISourceGenerator
         private const string TypeParameterVariableName = "______typeParameters";
 
 #if !ROSLYN_4
-
         /// <summary>
         /// Executes the specified context.
         /// </summary>
@@ -51,13 +45,11 @@ out var refitInternalNamespace
                 context.CancellationToken
             );
 
-            // Emit diagnostics
             foreach (var diagnostic in parseStep.diagnostics)
             {
                 context.ReportDiagnostic(diagnostic);
             }
 
-            // Emit interface stubs
             foreach (var interfaceModel in parseStep.contextGenerationSpec.Interfaces)
             {
                 var interfaceText = Emitter.EmitInterface(interfaceModel);
@@ -67,7 +59,6 @@ out var refitInternalNamespace
                 );
             }
 
-            // Emit PreserveAttribute and Generated.Initialize
             Emitter.EmitSharedCode(
                 parseStep.contextGenerationSpec,
                 (name, code) => context.AddSource(name, code)
@@ -76,15 +67,9 @@ out var refitInternalNamespace
 #endif
 
 #if ROSLYN_4
-
-        /// <summary>
-        /// Initializes the specified context.
-        /// </summary>
-        /// <param name="context">The context.</param>
-        /// <returns></returns>
+        /// <inheritdoc/>
         public void Initialize(IncrementalGeneratorInitializationContext context)
         {
-            // We're looking for methods with an attribute that are in an interface
             var candidateMethodsProvider = context.SyntaxProvider.CreateSyntaxProvider(
                 (syntax, cancellationToken) =>
                     syntax
@@ -96,8 +81,6 @@ is MethodDeclarationSyntax
                 (context, cancellationToken) => (MethodDeclarationSyntax)context.Node
             );
 
-            // We also look for interfaces that derive from others, so we can see if any base methods contain
-            // Refit methods
             var candidateInterfacesProvider = context.SyntaxProvider.CreateSyntaxProvider(
                 (syntax, cancellationToken) =>
                     syntax is InterfaceDeclarationSyntax { BaseList: not null },
@@ -146,9 +129,6 @@ out var refitInternalNamespace
                 }
             );
 
-            // output the diagnostics
-            // use `ImmutableEquatableArray` to cache cases where there are no diagnostics
-            // otherwise the subsequent steps will always rerun.
             var diagnostics = parseStep
                 .Select(static (x, _) => x.diagnostics.ToImmutableEquatableArray())
                 .WithTrackingName(RefitGeneratorStepName.ReportDiagnostics);
@@ -168,14 +148,11 @@ out var refitInternalNamespace
                 }
             );
         }
-
 #else
-
         /// <summary>
         /// Initializes the specified context.
         /// </summary>
         /// <param name="context">The context.</param>
-        /// <returns></returns>
         public void Initialize(GeneratorInitializationContext context)
         {
             context.RegisterForSyntaxNotifications(() => new SyntaxReceiver());
@@ -189,7 +166,6 @@ class SyntaxReceiver : ISyntaxReceiver
 
             public void OnVisitSyntaxNode(SyntaxNode syntaxNode)
             {
-                // We're looking for methods with an attribute that are in an interfaces
                 if (
                     syntaxNode is MethodDeclarationSyntax methodDeclarationSyntax
                     && methodDeclarationSyntax.Parent is InterfaceDeclarationSyntax
@@ -199,15 +175,12 @@ syntaxNode is MethodDeclarationSyntax methodDeclarationSyntax
                     CandidateMethods.Add(methodDeclarationSyntax);
                 }
 
-                // We also look for interfaces that derive from others, so we can see if any base methods contain
-                // Refit methods
                 if (syntaxNode is InterfaceDeclarationSyntax iface && iface.BaseList is not null)
                 {
                     CandidateInterfaces.Add(iface);
                 }
             }
         }
-
 #endif
     }
 

InterfaceStubGenerator.Shared/Models/MethodModel.cs

@@ -1,4 +1,6 @@
-namespace Refit.Generator;
+using System.Collections.Immutable;
+
+namespace Refit.Generator;
 
 internal sealed record MethodModel(
     string Name,
@@ -7,7 +9,8 @@ internal sealed record MethodModel(
     string DeclaredMethod,
     ReturnTypeInfo ReturnTypeMetadata,
     ImmutableEquatableArray<ParameterModel> Parameters,
-    ImmutableEquatableArray<TypeConstraint> Constraints
+    ImmutableEquatableArray<TypeConstraint> Constraints,
+    bool IsExplicitInterface
 );
 
 internal enum ReturnTypeInfo : byte

InterfaceStubGenerator.Shared/Models/WellKnownTypes.cs

@@ -2,16 +2,41 @@
 
 namespace Refit.Generator;
 
+/// <summary>
+/// WellKnownTypes.
+/// </summary>
 public class WellKnownTypes(Compilation compilation)
 {
-    readonly Dictionary<string, INamedTypeSymbol?> cachedTypes = new();
+    readonly Dictionary<string, INamedTypeSymbol?> cachedTypes = [];
 
+    /// <summary>
+    /// Gets this instance.
+    /// </summary>
+    /// <typeparam name="T"></typeparam>
+    /// <returns></returns>
     public INamedTypeSymbol Get<T>() => Get(typeof(T));
+
+    /// <summary>
+    /// Gets the specified type.
+    /// </summary>
+    /// <param name="type">The type.</param>
+    /// <returns></returns>
+    /// <exception cref="InvalidOperationException">Could not get name of type " + type</exception>
     public INamedTypeSymbol Get(Type type)
     {
+        if (type is null)
+        {
+            throw new ArgumentNullException(nameof(type));
+        }
+
         return Get(type.FullName ?? throw new InvalidOperationException("Could not get name of type " + type));
     }
 
+    /// <summary>
+    /// Tries the get.
+    /// </summary>
+    /// <param name="typeFullName">Full name of the type.</param>
+    /// <returns></returns>
     public INamedTypeSymbol? TryGet(string typeFullName)
     {
         if (cachedTypes.TryGetValue(typeFullName, out var typeSymbol))