Separate RequiredMappingStrategy configuration for enums (#1591)

Add MapperAttribute.RequiredEnumMappingStrategy / MapperDefaultsAttribute.RequiredEnumMappingStrategy
Resolve RequiredMappingStrategy for each enum mapping in the following order, fall back to the next one if the previous one is not set:
1.MapperRequiredMappingAttribute on the mapping method
2. MapperAttribute.RequiredEnumMappingStrategy
3. MapperDefaultsAttribute.RequiredEnumMappingStrategy
4. MapperAttribute.RequiredMappingStrategy
5. MapperDefaultsAttribute.RequiredMappingStrategy

docs/docs/configuration/enum.mdx

@@ -182,18 +182,18 @@ public partial class CarMapper
 
 By default Mapperly emits diagnostics with a severity of warning if there are unmapped source or target enum members.
 To enforce strict enum member mappings on only either the source or the target,
-the `RequiredMappingStrategy` can be used.
+the `RequiredEnumMappingStrategy` can be used. By default this property will inherit the value from `RequiredMappingStrategy`.
 
 <Tabs>
     <TabItem value="global" label="Global (mapper level)" default>
 
-        Sets the `RequiredMappingStrategy` for all methods within the mapper,
+        Sets the `RequiredEnumMappingStrategy` for all methods within the mapper,
         by default it is `Both` requiring all members to be mapped.
         This can be overriden by individual mapping methods using `MapperRequiredMappingAttribute`.
 
         ```csharp
         // highlight-start
-        [Mapper(RequiredMappingStrategy = RequiredMappingStrategy.Source)]
+        [Mapper(RequiredEnumMappingStrategy = RequiredMappingStrategy.Source)]
         // highlight-end
         public partial class CarMapper
         {

src/Riok.Mapperly.Abstractions/MapperAttribute.cs

@@ -101,6 +101,12 @@ public class MapperAttribute : Attribute
     /// </summary>
     public RequiredMappingStrategy RequiredMappingStrategy { get; set; } = RequiredMappingStrategy.Both;
 
+    /// <summary>
+    /// Defines the strategy used when emitting warnings for unmapped enum members.
+    /// By default this is <see cref="RequiredMappingStrategy.Both"/>, inheriting the strategy from <see cref="RequiredMappingStrategy"/>.
+    /// </summary>
+    public RequiredMappingStrategy RequiredEnumMappingStrategy { get; set; } = RequiredMappingStrategy.Both;
+
     /// <summary>
     /// Determines the access level of members that Mapperly will map.
     /// </summary>

src/Riok.Mapperly/Configuration/MapperConfiguration.cs

@@ -99,6 +99,12 @@ public record MapperConfiguration
     /// </summary>
     public RequiredMappingStrategy? RequiredMappingStrategy { get; init; }
 
+    /// <summary>
+    /// Defines the strategy used when emitting warnings for unmapped enum members.
+    /// By default this is <see cref="RequiredEnumMappingStrategy.Inherit"/>, inheriting the strategy from <see cref="RequiredMappingStrategy"/>.
+    /// </summary>
+    public RequiredMappingStrategy? RequiredEnumMappingStrategy { get; init; }
+
     /// <summary>
     /// Determines the access level of members that Mapperly will map.
     /// </summary>

src/Riok.Mapperly/Configuration/MapperConfigurationMerger.cs

@@ -51,6 +51,13 @@ public static MapperAttribute Merge(MapperConfiguration mapperConfiguration, Map
             ?? defaultMapperConfiguration.RequiredMappingStrategy
             ?? mapper.RequiredMappingStrategy;
 
+        mapper.RequiredEnumMappingStrategy =
+            mapperConfiguration.RequiredEnumMappingStrategy
+            ?? defaultMapperConfiguration.RequiredEnumMappingStrategy
+            ?? mapperConfiguration.RequiredMappingStrategy
+            ?? defaultMapperConfiguration.RequiredMappingStrategy
+            ?? mapper.RequiredMappingStrategy;
+
         mapper.IncludedMembers =
             mapperConfiguration.IncludedMembers ?? defaultMapperConfiguration.IncludedMembers ?? mapper.IncludedMembers;
 

src/Riok.Mapperly/Configuration/MapperConfigurationReader.cs

@@ -33,7 +33,7 @@ MapperConfiguration defaultMapperConfiguration
                 [],
                 [],
                 [],
-                mapper.RequiredMappingStrategy,
+                mapper.RequiredEnumMappingStrategy,
                 mapper.EnumNamingStrategy
             ),
             new MembersMappingConfiguration([], [], [], [], [], mapper.IgnoreObsoleteMembersStrategy, mapper.RequiredMappingStrategy),

test/Riok.Mapperly.Abstractions.Tests/_snapshots/PublicApiTest.PublicApiHasNotChanged.verified.cs

@@ -132,6 +132,7 @@ public MapperAttribute() { }
         public Riok.Mapperly.Abstractions.MemberVisibility IncludedMembers { get; set; }
         public bool PreferParameterlessConstructors { get; set; }
         public Riok.Mapperly.Abstractions.PropertyNameMappingStrategy PropertyNameMappingStrategy { get; set; }
+        public Riok.Mapperly.Abstractions.RequiredMappingStrategy RequiredEnumMappingStrategy { get; set; }
         public Riok.Mapperly.Abstractions.RequiredMappingStrategy RequiredMappingStrategy { get; set; }
         public bool ThrowOnMappingNullMismatch { get; set; }
         public bool ThrowOnPropertyMappingNullMismatch { get; set; }

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

@@ -19,6 +19,25 @@ public void MapperAttributeRequiredMappingNoneWithUnmappedMembersShouldNotDiagno
         TestHelper.GenerateMapper(source).Should().HaveSingleMethodBody("return (global::E2)source;");
     }
 
+    [Fact]
+    public void MapperAttributeRequiredEnumMappingSourceAndRequiredMappingNoneWithUnmappedMember()
+    {
+        var source = TestSourceBuilder.Mapping(
+            "E1",
+            "E2",
+            TestSourceBuilderOptions.WithRequiredEnumMappingStrategy(RequiredMappingStrategy.Source, RequiredMappingStrategy.None),
+            "enum E1 { V1, V2, V3 }",
+            "enum E2 { V1, V2 }"
+        );
+
+        TestHelper
+            .GenerateMapper(source, TestHelperOptions.AllowDiagnostics)
+            .Should()
+            .HaveDiagnostic(DiagnosticDescriptors.SourceEnumValueNotMapped, "Enum member V3 (2) on E1 not found on target enum E2")
+            .HaveAssertedAllDiagnostics()
+            .HaveSingleMethodBody("return (global::E2)source;");
+    }
+
     [Fact]
     public void MapperAttributeRequiredMappingSourceWithUnmappedMember()
     {
@@ -70,6 +89,25 @@ TestSourceBuilderOptions.Default with
             );
     }
 
+    [Fact]
+    public void MapperAttributeRequiredEnumMappingTargetAndRequiredMappingNoneWithUnmappedMember()
+    {
+        var source = TestSourceBuilder.Mapping(
+            "E1",
+            "E2",
+            TestSourceBuilderOptions.WithRequiredEnumMappingStrategy(RequiredMappingStrategy.Target, RequiredMappingStrategy.None),
+            "enum E1 { V1, V2 }",
+            "enum E2 { V1, V2, V3 }"
+        );
+
+        TestHelper
+            .GenerateMapper(source, TestHelperOptions.AllowDiagnostics)
+            .Should()
+            .HaveDiagnostic(DiagnosticDescriptors.TargetEnumValueNotMapped, "Enum member V3 (2) on E2 not found on source enum E1")
+            .HaveAssertedAllDiagnostics()
+            .HaveSingleMethodBody("return (global::E2)source;");
+    }
+
     [Fact]
     public void MapperAttributeRequiredMappingTargetWithUnmappedMember()
     {

test/Riok.Mapperly.Tests/TestSourceBuilder.cs

@@ -94,6 +94,7 @@ private static string BuildAttribute(TestSourceBuilderOptions options)
             Attribute(options.EnumMappingIgnoreCase),
             Attribute(options.IgnoreObsoleteMembersStrategy),
             Attribute(options.RequiredMappingStrategy),
+            Attribute(options.RequiredEnumMappingStrategy),
             Attribute(options.IncludedMembers),
             Attribute(options.IncludedConstructors),
             Attribute(options.PreferParameterlessConstructors),

test/Riok.Mapperly.Tests/TestSourceBuilderOptions.cs

@@ -17,6 +17,7 @@ public record TestSourceBuilderOptions(
     bool? EnumMappingIgnoreCase = null,
     IgnoreObsoleteMembersStrategy? IgnoreObsoleteMembersStrategy = null,
     RequiredMappingStrategy? RequiredMappingStrategy = null,
+    RequiredMappingStrategy? RequiredEnumMappingStrategy = null,
     MemberVisibility? IncludedMembers = null,
     MemberVisibility? IncludedConstructors = null,
     bool Static = false,
@@ -42,6 +43,11 @@ public static TestSourceBuilderOptions WithIgnoreObsolete(IgnoreObsoleteMembersS
     public static TestSourceBuilderOptions WithRequiredMappingStrategy(RequiredMappingStrategy requiredMappingStrategy) =>
         new(RequiredMappingStrategy: requiredMappingStrategy);
 
+    public static TestSourceBuilderOptions WithRequiredEnumMappingStrategy(
+        RequiredMappingStrategy requiredEnumMappingStrategy,
+        RequiredMappingStrategy requiredMappingStrategy
+    ) => new(RequiredEnumMappingStrategy: requiredEnumMappingStrategy, RequiredMappingStrategy: requiredMappingStrategy);
+
     public static TestSourceBuilderOptions WithMemberVisibility(MemberVisibility memberVisibility) =>
         new(IncludedMembers: memberVisibility);