fix: support multiple mappers with the same name in different namespa…

…ces (#123)

src/Riok.Mapperly/Descriptors/DescriptorBuilder.cs

@@ -60,7 +60,7 @@ public DescriptorBuilder(
         _mapperSymbol = mapperSymbol;
         _context = sourceContext;
         Compilation = compilation;
-        _mapperDescriptor = new MapperDescriptor(mapperSymbol.Name, mapperSyntax, mapperSymbol.IsStatic);
+        _mapperDescriptor = new MapperDescriptor(mapperSyntax, mapperSymbol.IsStatic);
         MapperConfiguration = Configure();
     }
 

src/Riok.Mapperly/Descriptors/MapperDescriptor.cs

@@ -5,21 +5,17 @@ namespace Riok.Mapperly.Descriptors;
 
 public class MapperDescriptor
 {
-    private const string FileNameSuffix = ".g.cs";
 
     private readonly List<TypeMapping> _mappings = new();
 
-    public MapperDescriptor(string name, ClassDeclarationSyntax syntax, bool isStatic)
+    public MapperDescriptor(ClassDeclarationSyntax syntax, bool isStatic)
     {
-        FileName = name + FileNameSuffix;
         Syntax = syntax;
         IsStatic = isStatic;
     }
 
     public string? Namespace { get; set; }
 
-    public string FileName { get; }
-
     public ClassDeclarationSyntax Syntax { get; }
 
     public bool IsStatic { get; }

src/Riok.Mapperly/MapperGenerator.cs

@@ -13,6 +13,7 @@ namespace Riok.Mapperly;
 [Generator]
 public class MapperGenerator : IIncrementalGenerator
 {
+    private const string GeneratedFileSuffix = ".g.cs";
     private static readonly string _mapperAttributeName = typeof(MapperAttribute).FullName;
 
     public void Initialize(IncrementalGeneratorInitializationContext context)
@@ -61,6 +62,7 @@ private static void Execute(Compilation compilation, ImmutableArray<ClassDeclara
         if (mapperAttributeSymbol == null)
             return;
 
+        var uniqueNameBuilder = new UniqueNameBuilder();
         foreach (var mapperSyntax in mappers.Distinct())
         {
             var mapperModel = compilation.GetSemanticModel(mapperSyntax.SyntaxTree);
@@ -74,7 +76,7 @@ private static void Execute(Compilation compilation, ImmutableArray<ClassDeclara
             var descriptor = builder.Build();
 
             ctx.AddSource(
-                descriptor.FileName,
+                uniqueNameBuilder.Build(mapperSymbol.Name) + GeneratedFileSuffix,
                 SourceText.From(SourceEmitter.Build(descriptor).ToFullString(), Encoding.UTF8));
         }
     }

test/Riok.Mapperly.Tests/Mapping/MapperTest.cs

@@ -0,0 +1,33 @@
+namespace Riok.Mapperly.Tests.Mapping;
+
+[UsesVerify]
+public class MapperTest
+{
+    [Fact]
+    public Task SameMapperNameInMultipleNamespacesShouldWork()
+    {
+        var source = @"
+using Riok.Mapperly.Abstractions;
+
+namespace Test.A
+{
+    [Mapper]
+    internal partial class FooBarMapper
+    {
+        internal partial string FooToBar(string value);
+    }
+}
+
+namespace Test.B
+{
+    [Mapper]
+    internal partial class FooBarMapper
+    {
+        internal partial string FooToBar(string value);
+    }
+}
+";
+
+        return TestHelper.VerifyGenerator(source);
+    }
+}

test/Riok.Mapperly.Tests/_snapshots/MapperTest.SameMapperNameInMultipleNamespacesShouldWork.00FooBarMapper.g.verified.cs

@@ -0,0 +1,12 @@
+//HintName: FooBarMapper.g.cs
+#nullable enable
+namespace Test.A
+{
+    internal partial class FooBarMapper
+    {
+        internal partial string FooToBar(string value)
+        {
+            return value;
+        }
+    }
+}

test/Riok.Mapperly.Tests/_snapshots/MapperTest.SameMapperNameInMultipleNamespacesShouldWork.01FooBarMapper1.g.verified.cs

@@ -0,0 +1,12 @@
+//HintName: FooBarMapper1.g.cs
+#nullable enable
+namespace Test.B
+{
+    internal partial class FooBarMapper
+    {
+        internal partial string FooToBar(string value)
+        {
+            return value;
+        }
+    }
+}