feat: queryable support for user implemented mappings (#348)

docs/docs/02-configuration/11-queryable-projections.mdx

@@ -45,10 +45,10 @@ such mappings have several limitations:
 - Object factories are not applied
 - Constructors with unmatched optional parameters are ignored
 - `ThrowOnPropertyMappingNullMismatch` is ignored
-- User implemented mappings are not supported
 - Enum mappings do not support the `ByName` strategy
 - Reference handling is not supported
 - Nullable reference types are disabled
+- User implemented mapping methods need to follow expression tree [limitations](https://learn.microsoft.com/en-us/dotnet/csharp/advanced-topics/expression-trees/#limitations).
 
 :::
 

src/Riok.Mapperly/Descriptors/InlineExpressionMappingBuilderContext.cs

@@ -13,6 +13,7 @@ namespace Riok.Mapperly.Descriptors;
 public class InlineExpressionMappingBuilderContext : MappingBuilderContext
 {
     private readonly MappingCollection _inlineExpressionMappings;
+    private readonly MappingBuilderContext _parentContext;
 
     public InlineExpressionMappingBuilderContext(MappingBuilderContext ctx, ITypeSymbol sourceType, ITypeSymbol targetType)
         : this(ctx, (ctx.FindMapping(sourceType, targetType) as IUserMapping)?.Method, sourceType, targetType)
@@ -26,6 +27,7 @@ private InlineExpressionMappingBuilderContext(
         ITypeSymbol target)
         : base(ctx, userSymbol, source, target)
     {
+        _parentContext = ctx;
         _inlineExpressionMappings = new MappingCollection();
     }
 
@@ -36,6 +38,7 @@ private InlineExpressionMappingBuilderContext(
         ITypeSymbol target)
         : base(ctx, userSymbol, source, target)
     {
+        _parentContext = ctx;
         _inlineExpressionMappings = ctx._inlineExpressionMappings;
     }
 
@@ -53,12 +56,28 @@ and not MappingConversionType.Dictionary
     /// <summary>
     /// Tries to find an existing mapping for the provided types.
     /// The nullable annotation of reference types is ignored and always set to non-nullable.
+    /// Only inline expression mappings and user implemented mappings are considered.
     /// </summary>
     /// <param name="sourceType">The source type.</param>
     /// <param name="targetType">The target type.</param>
     /// <returns>The <see cref="ITypeMapping"/> if a mapping was found or <c>null</c> if none was found.</returns>
     public override ITypeMapping? FindMapping(ITypeSymbol sourceType, ITypeSymbol targetType)
-        => _inlineExpressionMappings.Find(sourceType, targetType);
+    {
+        if (_inlineExpressionMappings.Find(sourceType, targetType) is { } mapping)
+            return mapping;
+
+        // user implemented mappings are also taken into account
+        // this works as long as the user implemented methods
+        // follow the expression tree limitations:
+        // https://learn.microsoft.com/en-us/dotnet/csharp/advanced-topics/expression-trees/#limitations
+        if (_parentContext.FindMapping(sourceType, targetType) is UserImplementedMethodMapping userMapping)
+        {
+            _inlineExpressionMappings.Add(userMapping);
+            return userMapping;
+        }
+
+        return null;
+    }
 
     /// <summary>
     /// Existing target instance mappings are not supported.

test/Riok.Mapperly.IntegrationTests/Dto/TestObjectDtoManuallyMappedProjection.cs

@@ -0,0 +1,14 @@
+namespace Riok.Mapperly.IntegrationTests.Dto
+{
+    public class TestObjectDtoManuallyMappedProjection
+    {
+        public TestObjectDtoManuallyMappedProjection(int magicIntValue)
+        {
+            MagicIntValue = magicIntValue;
+        }
+
+        public int MagicIntValue { get; }
+
+        public string? StringValue { get; set; }
+    }
+}

test/Riok.Mapperly.IntegrationTests/Dto/TestObjectDtoProjection.cs

@@ -51,7 +51,7 @@ public TestObjectDtoProjection(int ctorValue)
 
         public string EnumStringValue { get; set; } = string.Empty;
 
-        public TestEnumDtoByValue EnumReverseStringValue { get; set; }
+        public TestEnumDtoByName EnumReverseStringValue { get; set; }
 
         public InheritanceSubObjectDto? SubObject { get; set; }
 
@@ -61,5 +61,7 @@ public TestObjectDtoProjection(int ctorValue)
         public DateOnly DateTimeValueTargetDateOnly { get; set; }
 
         public TimeOnly DateTimeValueTargetTimeOnly { get; set; }
+
+        public TestObjectDtoManuallyMappedProjection? ManuallyMapped { get; set; }
     }
 }

test/Riok.Mapperly.IntegrationTests/Mapper/ProjectionMapper.cs

@@ -18,5 +18,13 @@ public static partial class ProjectionMapper
         [MapperIgnoreSource(nameof(TestObjectProjection.IgnoredStringValue))]
         [MapProperty(nameof(TestObjectProjection.RenamedStringValue), nameof(TestObjectDtoProjection.RenamedStringValue2))]
         private static partial TestObjectDtoProjection ProjectToDto(this TestObjectProjection testObject);
+
+        private static TestObjectDtoManuallyMappedProjection? MapManual(string str)
+        {
+            return new TestObjectDtoManuallyMappedProjection(100)
+            {
+                StringValue = str,
+            };
+        }
     }
 }

test/Riok.Mapperly.IntegrationTests/Models/TestObjectProjection.cs

@@ -60,5 +60,7 @@ public class TestObjectProjection
         public DateTime DateTimeValueTargetDateOnly { get; set; }
 
         public DateTime DateTimeValueTargetTimeOnly { get; set; }
+
+        public String ManuallyMapped { get; set; } = "fooBar";
     }
 }

test/Riok.Mapperly.IntegrationTests/ProjectionMapperTest.cs

@@ -1,10 +1,11 @@
+using System;
 using System.Threading.Tasks;
-using FluentAssertions;
 using Riok.Mapperly.IntegrationTests.Mapper;
 using Riok.Mapperly.IntegrationTests.Models;
 using VerifyXunit;
 using Xunit;
 #if NET7_0_OR_GREATER
+using Microsoft.Data.Sqlite;
 using Microsoft.EntityFrameworkCore;
 #endif
 
@@ -22,38 +23,76 @@ public Task SnapshotGeneratedSource()
 
 #if NET7_0_OR_GREATER
         [Fact]
-        public void ProjectionShouldTranslateToQuery()
+        public async Task ProjectionShouldTranslateToQuery()
         {
-            using var ctx = new ProjectionDbContext();
-            var query = ctx.Objects.ProjectToDto().ToQueryString();
-            query.Should().Be(
-                """
-                SELECT "o"."CtorValue", "o"."IntValue", "o"."IntInitOnlyValue", "o"."RequiredValue", "o"."StringValue", "o"."RenamedStringValue", "i"."IdValue", CASE
-                    WHEN "i0"."IdValue" IS NOT NULL THEN "i0"."IdValue"
-                    ELSE 0
-                END, CASE
-                    WHEN "t"."IntValue" IS NOT NULL THEN "t"."IntValue"
-                    ELSE 0
-                END, "t"."IntValue" IS NOT NULL, "t"."IntValue", "t0"."IntValue" IS NOT NULL, "t0"."IntValue", COALESCE("o"."StringNullableTargetNotNullable", ''), "o0"."IntValue", "o0"."CtorValue", "o0"."DateTimeValueTargetDateOnly", "o0"."DateTimeValueTargetTimeOnly", "o0"."EnumName", "o0"."EnumRawValue", "o0"."EnumReverseStringValue", "o0"."EnumStringValue", "o0"."EnumValue", "o0"."FlatteningIdValue", "o0"."IgnoredIntValue", "o0"."IgnoredStringValue", "o0"."IntInitOnlyValue", "o0"."NestedNullableIntValue", "o0"."NestedNullableTargetNotNullableIntValue", "o0"."NullableFlatteningIdValue", "o0"."NullableUnflatteningIdValue", "o0"."RecursiveObjectIntValue", "o0"."RenamedStringValue", "o0"."RequiredValue", "o0"."StringNullableTargetNotNullable", "o0"."StringValue", "o0"."SubObjectSubIntValue", "o0"."UnflatteningIdValue", "i0"."IdValue", "i1"."SubIntValue", "t1"."IntValue", "t1"."TestObjectProjectionIntValue", "t2"."IntValue", CAST("o"."EnumValue" AS INTEGER), CAST("o"."EnumName" AS INTEGER), CAST("o"."EnumRawValue" AS INTEGER), "o"."EnumStringValue", "o"."EnumReverseStringValue", "i1"."SubIntValue" IS NOT NULL, "i1"."BaseIntValue", "o"."DateTimeValueTargetDateOnly", "o"."DateTimeValueTargetTimeOnly"
-                FROM "Objects" AS "o"
-                INNER JOIN "IdObject" AS "i" ON "o"."FlatteningIdValue" = "i"."IdValue"
-                LEFT JOIN "IdObject" AS "i0" ON "o"."NullableFlatteningIdValue" = "i0"."IdValue"
-                LEFT JOIN "TestObjectNested" AS "t" ON "o"."NestedNullableIntValue" = "t"."IntValue"
-                LEFT JOIN "TestObjectNested" AS "t0" ON "o"."NestedNullableTargetNotNullableIntValue" = "t0"."IntValue"
-                LEFT JOIN "Objects" AS "o0" ON "o"."IntValue" = "o0"."RecursiveObjectIntValue"
-                LEFT JOIN "InheritanceSubObject" AS "i1" ON "o"."SubObjectSubIntValue" = "i1"."SubIntValue"
-                LEFT JOIN "TestObjectNested" AS "t1" ON "o"."IntValue" = "t1"."TestObjectProjectionIntValue"
-                LEFT JOIN "TestObjectNested" AS "t2" ON "o"."IntValue" = "t2"."TestObjectProjectionIntValue"
-                ORDER BY "o"."IntValue", "i"."IdValue", "i0"."IdValue", "t"."IntValue", "t0"."IntValue", "o0"."IntValue", "i1"."SubIntValue", "t1"."IntValue"
-                """);
+            await using var connection = new SqliteConnection("Data Source=:memory:");
+            await connection.OpenAsync();
+
+            var options = new DbContextOptionsBuilder()
+                .UseSqlite(connection)
+                .Options;
+
+            await using var ctx = new ProjectionDbContext(options);
+            await ctx.Database.EnsureCreatedAsync();
+            ctx.Objects.Add(CreateObject());
+            await ctx.SaveChangesAsync();
+
+            var query = ctx.Objects.ProjectToDto();
+            await Verifier
+                .Verify(query.ToQueryString(), "sql")
+                .UseTextForParameters("query");
+
+            var objects = await query.ToListAsync();
+            await Verifier
+                .Verify(objects)
+                .UseTextForParameters("result");
+        }
+
+        private TestObjectProjection CreateObject()
+        {
+            return new TestObjectProjection
+            {
+                RequiredValue = 10,
+                EnumName = TestEnum.Value10,
+                EnumReverseStringValue = nameof(TestEnum.Value10),
+                EnumValue = TestEnum.Value20,
+                IntValue = 100,
+                EnumRawValue = TestEnum.Value30,
+                EnumStringValue = TestEnum.Value10,
+                Flattening = new IdObject { IdValue = 10 },
+                CtorValue = 2,
+                IgnoredIntValue = 3,
+                IntInitOnlyValue = 4,
+                StringNullableTargetNotNullable = "fooBar",
+                DateTimeValueTargetTimeOnly = new DateTime(2018, 11, 29, 10, 11, 12),
+                DateTimeValueTargetDateOnly = new DateTime(2018, 11, 29, 10, 11, 12),
+                RenamedStringValue = "fooBar2",
+                UnflatteningIdValue = 7,
+                StringValue = "fooBar3",
+                IgnoredStringValue = "fooBar4",
+                NullableFlattening = new IdObject { IdValue = 20 },
+                SubObject = new InheritanceSubObject
+                {
+                    BaseIntValue = 10,
+                    SubIntValue = 20,
+                },
+                RecursiveObject = new TestObjectProjection
+                {
+                    RequiredValue = -1,
+                    EnumName = TestEnum.Value10,
+                    EnumReverseStringValue = nameof(TestEnum.Value10),
+                    EnumValue = TestEnum.Value20,
+                },
+            };
         }
 
         class ProjectionDbContext : DbContext
         {
-            public DbSet<TestObjectProjection> Objects { get; set; } = null!;
+            public ProjectionDbContext(DbContextOptions options) : base(options)
+            {
+            }
 
-            protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
-                => optionsBuilder.UseSqlite("Data Source=:memory:");
+            public DbSet<TestObjectProjection> Objects { get; set; } = null!;
 
             protected override void OnModelCreating(ModelBuilder modelBuilder)
             {

test/Riok.Mapperly.IntegrationTests/_snapshots/NET_48/ProjectionMapperTest.SnapshotGeneratedSource.verified.cs

@@ -6,7 +6,7 @@ public static partial class ProjectionMapper
         public static partial global::System.Linq.IQueryable<global::Riok.Mapperly.IntegrationTests.Dto.TestObjectDtoProjection> ProjectToDto(this global::System.Linq.IQueryable<global::Riok.Mapperly.IntegrationTests.Models.TestObjectProjection> q)
         {
 #nullable disable
-            return System.Linq.Queryable.Select(q, x => new global::Riok.Mapperly.IntegrationTests.Dto.TestObjectDtoProjection(x.CtorValue) { IntValue = x.IntValue, IntInitOnlyValue = x.IntInitOnlyValue, RequiredValue = x.RequiredValue, StringValue = x.StringValue, RenamedStringValue2 = x.RenamedStringValue, FlatteningIdValue = x.Flattening.IdValue, NullableFlatteningIdValue = x.NullableFlattening != null ? x.NullableFlattening.IdValue : default, NestedNullableIntValue = x.NestedNullable != null ? x.NestedNullable.IntValue : default, NestedNullable = x.NestedNullable != null ? new global::Riok.Mapperly.IntegrationTests.Dto.TestObjectNestedDto() { IntValue = x.NestedNullable.IntValue } : default, NestedNullableTargetNotNullable = x.NestedNullableTargetNotNullable != null ? new global::Riok.Mapperly.IntegrationTests.Dto.TestObjectNestedDto() { IntValue = x.NestedNullableTargetNotNullable.IntValue } : new global::Riok.Mapperly.IntegrationTests.Dto.TestObjectNestedDto(), StringNullableTargetNotNullable = x.StringNullableTargetNotNullable ?? "", SourceTargetSameObjectType = x.SourceTargetSameObjectType, NullableReadOnlyObjectCollection = x.NullableReadOnlyObjectCollection != null ? global::System.Linq.Enumerable.ToArray(global::System.Linq.Enumerable.Select(x.NullableReadOnlyObjectCollection, x1 => new global::Riok.Mapperly.IntegrationTests.Dto.TestObjectNestedDto() { IntValue = x1.IntValue })) : default, EnumValue = (global::Riok.Mapperly.IntegrationTests.Dto.TestEnumDtoByValue)x.EnumValue, EnumName = (global::Riok.Mapperly.IntegrationTests.Dto.TestEnumDtoByName)x.EnumName, EnumRawValue = (byte)x.EnumRawValue, EnumStringValue = (string)x.EnumStringValue.ToString(), EnumReverseStringValue = (global::Riok.Mapperly.IntegrationTests.Dto.TestEnumDtoByValue)System.Enum.Parse(typeof(global::Riok.Mapperly.IntegrationTests.Dto.TestEnumDtoByValue), x.EnumReverseStringValue, false), SubObject = x.SubObject != null ? new global::Riok.Mapperly.IntegrationTests.Dto.InheritanceSubObjectDto() { SubIntValue = x.SubObject.SubIntValue, BaseIntValue = x.SubObject.BaseIntValue } : default, DateTimeValueTargetDateOnly = global::System.DateOnly.FromDateTime(x.DateTimeValueTargetDateOnly), DateTimeValueTargetTimeOnly = global::System.TimeOnly.FromDateTime(x.DateTimeValueTargetTimeOnly) });
+            return System.Linq.Queryable.Select(q, x => new global::Riok.Mapperly.IntegrationTests.Dto.TestObjectDtoProjection(x.CtorValue) { IntValue = x.IntValue, IntInitOnlyValue = x.IntInitOnlyValue, RequiredValue = x.RequiredValue, StringValue = x.StringValue, RenamedStringValue2 = x.RenamedStringValue, FlatteningIdValue = x.Flattening.IdValue, NullableFlatteningIdValue = x.NullableFlattening != null ? x.NullableFlattening.IdValue : default, NestedNullableIntValue = x.NestedNullable != null ? x.NestedNullable.IntValue : default, NestedNullable = x.NestedNullable != null ? new global::Riok.Mapperly.IntegrationTests.Dto.TestObjectNestedDto() { IntValue = x.NestedNullable.IntValue } : default, NestedNullableTargetNotNullable = x.NestedNullableTargetNotNullable != null ? new global::Riok.Mapperly.IntegrationTests.Dto.TestObjectNestedDto() { IntValue = x.NestedNullableTargetNotNullable.IntValue } : new global::Riok.Mapperly.IntegrationTests.Dto.TestObjectNestedDto(), StringNullableTargetNotNullable = x.StringNullableTargetNotNullable ?? "", SourceTargetSameObjectType = x.SourceTargetSameObjectType, NullableReadOnlyObjectCollection = x.NullableReadOnlyObjectCollection != null ? global::System.Linq.Enumerable.ToArray(global::System.Linq.Enumerable.Select(x.NullableReadOnlyObjectCollection, x1 => new global::Riok.Mapperly.IntegrationTests.Dto.TestObjectNestedDto() { IntValue = x1.IntValue })) : default, EnumValue = (global::Riok.Mapperly.IntegrationTests.Dto.TestEnumDtoByValue)x.EnumValue, EnumName = (global::Riok.Mapperly.IntegrationTests.Dto.TestEnumDtoByName)x.EnumName, EnumRawValue = (byte)x.EnumRawValue, EnumStringValue = (string)x.EnumStringValue.ToString(), EnumReverseStringValue = (global::Riok.Mapperly.IntegrationTests.Dto.TestEnumDtoByName)System.Enum.Parse(typeof(global::Riok.Mapperly.IntegrationTests.Dto.TestEnumDtoByName), x.EnumReverseStringValue, false), SubObject = x.SubObject != null ? new global::Riok.Mapperly.IntegrationTests.Dto.InheritanceSubObjectDto() { SubIntValue = x.SubObject.SubIntValue, BaseIntValue = x.SubObject.BaseIntValue } : default, DateTimeValueTargetDateOnly = global::System.DateOnly.FromDateTime(x.DateTimeValueTargetDateOnly), DateTimeValueTargetTimeOnly = global::System.TimeOnly.FromDateTime(x.DateTimeValueTargetTimeOnly), ManuallyMapped = MapManual(x.ManuallyMapped) });
 #nullable enable
         }
 
@@ -53,9 +53,10 @@ public static partial class ProjectionMapper
             target.EnumName = (global::Riok.Mapperly.IntegrationTests.Dto.TestEnumDtoByName)testObject.EnumName;
             target.EnumRawValue = (byte)testObject.EnumRawValue;
             target.EnumStringValue = MapToString(testObject.EnumStringValue);
-            target.EnumReverseStringValue = MapToTestEnumDtoByValue(testObject.EnumReverseStringValue);
+            target.EnumReverseStringValue = MapToTestEnumDtoByName(testObject.EnumReverseStringValue);
             target.DateTimeValueTargetDateOnly = global::System.DateOnly.FromDateTime(testObject.DateTimeValueTargetDateOnly);
             target.DateTimeValueTargetTimeOnly = global::System.TimeOnly.FromDateTime(testObject.DateTimeValueTargetTimeOnly);
+            target.ManuallyMapped = MapManual(testObject.ManuallyMapped);
             return target;
         }
 
@@ -77,14 +78,14 @@ private static string MapToString(global::Riok.Mapperly.IntegrationTests.Models.
             };
         }
 
-        private static global::Riok.Mapperly.IntegrationTests.Dto.TestEnumDtoByValue MapToTestEnumDtoByValue(string source)
+        private static global::Riok.Mapperly.IntegrationTests.Dto.TestEnumDtoByName MapToTestEnumDtoByName(string source)
         {
             return source switch
             {
-                nameof(global::Riok.Mapperly.IntegrationTests.Dto.TestEnumDtoByValue.DtoValue1) => global::Riok.Mapperly.IntegrationTests.Dto.TestEnumDtoByValue.DtoValue1,
-                nameof(global::Riok.Mapperly.IntegrationTests.Dto.TestEnumDtoByValue.DtoValue2) => global::Riok.Mapperly.IntegrationTests.Dto.TestEnumDtoByValue.DtoValue2,
-                nameof(global::Riok.Mapperly.IntegrationTests.Dto.TestEnumDtoByValue.DtoValue3) => global::Riok.Mapperly.IntegrationTests.Dto.TestEnumDtoByValue.DtoValue3,
-                _ => (global::Riok.Mapperly.IntegrationTests.Dto.TestEnumDtoByValue)System.Enum.Parse(typeof(global::Riok.Mapperly.IntegrationTests.Dto.TestEnumDtoByValue), source, false),
+                nameof(global::Riok.Mapperly.IntegrationTests.Dto.TestEnumDtoByName.Value10) => global::Riok.Mapperly.IntegrationTests.Dto.TestEnumDtoByName.Value10,
+                nameof(global::Riok.Mapperly.IntegrationTests.Dto.TestEnumDtoByName.Value20) => global::Riok.Mapperly.IntegrationTests.Dto.TestEnumDtoByName.Value20,
+                nameof(global::Riok.Mapperly.IntegrationTests.Dto.TestEnumDtoByName.Value30) => global::Riok.Mapperly.IntegrationTests.Dto.TestEnumDtoByName.Value30,
+                _ => (global::Riok.Mapperly.IntegrationTests.Dto.TestEnumDtoByName)System.Enum.Parse(typeof(global::Riok.Mapperly.IntegrationTests.Dto.TestEnumDtoByName), source, false),
             };
         }
 
@@ -96,4 +97,4 @@ private static string MapToString(global::Riok.Mapperly.IntegrationTests.Models.
             return target;
         }
     }
-}
+}