support for rewriting null conditional access expressions

tests/EntityFrameworkCore.Projectables.FunctionalTests/ExtensionsMethods/EntityExtensions.cs

@@ -11,8 +11,8 @@ namespace EntityFrameworkCore.Projectables.FunctionalTests.ExtensionMethods
         [Projectable]
         public static int Foo(this Entity entity) => entity.Id + 1;
 
-            [Projectable]
-            public static int Foo2(this Entity entity) => entity.Foo() + 1;
+        [Projectable]
+        public static int Foo2(this Entity entity) => entity.Foo() + 1;
 
         [Projectable]
         public static Entity? LeadingEntity(this Entity entity, DbContext dbContext)

tests/EntityFrameworkCore.Projectables.FunctionalTests/NullConditionals/Entity.cs

@@ -0,0 +1,11 @@
+using System.Collections.Generic;
+
+namespace EntityFrameworkCore.Projectables.FunctionalTests.NullConditionals
+{
+    public record Entity
+    {
+        public int Id { get; set; }
+        public string? Name { get; set; }
+        public List<Entity>? RelatedEntities { get; set; }
+    }
+}

tests/EntityFrameworkCore.Projectables.FunctionalTests/NullConditionals/EntityExtensions.cs

@@ -0,0 +1,31 @@
+#nullable disable
+
+namespace EntityFrameworkCore.Projectables.FunctionalTests.NullConditionals
+{
+    public static class EntityExtensions
+    {
+        [Projectable(NullConditionalRewriteSupport = NullConditionalRewriteSupport.Ignore)]
+        public static string GetNameIgnoreNulls(this Entity entity)
+            => entity?.Name;
+
+        [Projectable(NullConditionalRewriteSupport = NullConditionalRewriteSupport.Ignore)]
+        public static int? GetNameLengthIgnoreNulls(this Entity entity)
+            => entity.GetNameIgnoreNulls()?.Length;
+
+        [Projectable(NullConditionalRewriteSupport = NullConditionalRewriteSupport.Ignore)]
+        public static Entity GetFirstRelatedIgnoreNulls(this Entity entity)
+            => entity?.RelatedEntities?[0];
+
+        [Projectable(NullConditionalRewriteSupport = NullConditionalRewriteSupport.Rewrite)]
+        public static string GetNameRewriteNulls(this Entity entity)
+            => entity?.Name;
+
+        [Projectable(NullConditionalRewriteSupport = NullConditionalRewriteSupport.Rewrite)]
+        public static int? GetNameLengthRewriteNulls(this Entity entity)
+            => entity.GetNameIgnoreNulls()?.Length;
+
+        [Projectable(NullConditionalRewriteSupport = NullConditionalRewriteSupport.Rewrite)]
+        public static Entity GetFirstRelatedRewriteNulls(this Entity entity)
+            => entity?.RelatedEntities?[0];
+    }
+}

tests/EntityFrameworkCore.Projectables.FunctionalTests/NullConditionals/IngoreNullConditionalRewriteTests.ComplexMemberExpression.verified.txt

@@ -0,0 +1,2 @@
+SELECT CAST(LEN([e].[Name]) AS int)
+FROM [Entity] AS [e]

tests/EntityFrameworkCore.Projectables.FunctionalTests/NullConditionals/IngoreNullConditionalRewriteTests.RelationalExpression.verified.txt

@@ -0,0 +1,4 @@
+SELECT [e].[Id], [e0].[Id], [e0].[EntityId], [e0].[Name]
+FROM [Entity] AS [e]
+LEFT JOIN [Entity] AS [e0] ON [e].[Id] = [e0].[EntityId]
+ORDER BY [e].[Id]

tests/EntityFrameworkCore.Projectables.FunctionalTests/NullConditionals/IngoreNullConditionalRewriteTests.SimpleMemberExpression.verified.txt

@@ -0,0 +1,2 @@
+SELECT [e].[Name]
+FROM [Entity] AS [e]

tests/EntityFrameworkCore.Projectables.FunctionalTests/NullConditionals/IngoreNullConditionalRewriteTests.cs

@@ -0,0 +1,48 @@
+using System;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using EntityFrameworkCore.Projectables.FunctionalTests.Helpers;
+using Microsoft.EntityFrameworkCore;
+using VerifyXunit;
+using Xunit;
+
+namespace EntityFrameworkCore.Projectables.FunctionalTests.NullConditionals
+{
+    [UsesVerify]
+    public class IngoreNullConditionalRewriteTests
+    {
+        [Fact]
+        public Task SimpleMemberExpression()
+        {
+            using var dbContext = new SampleDbContext<Entity>();
+
+            var query = dbContext.Set<Entity>()
+                .Select(x => x.GetNameIgnoreNulls());
+
+            return Verifier.Verify(query.ToQueryString());
+        }
+
+        [Fact]
+        public Task ComplexMemberExpression()
+        {
+            using var dbContext = new SampleDbContext<Entity>();
+
+            var query = dbContext.Set<Entity>()
+                .Select(x => x.GetNameLengthIgnoreNulls());
+
+            return Verifier.Verify(query.ToQueryString());
+        }
+
+        [Fact]
+        public Task RelationalExpression()
+        {
+            using var dbContext = new SampleDbContext<Entity>();
+
+            var query = dbContext.Set<Entity>()
+                .Select(x => x.GetFirstRelatedIgnoreNulls());
+
+            return Verifier.Verify(query.ToQueryString());
+        }
+    }
+}

tests/EntityFrameworkCore.Projectables.FunctionalTests/NullConditionals/RewriteNullConditionalRewriteTests.ComplexMemberExpression.verified.txt

@@ -0,0 +1,2 @@
+SELECT CAST(LEN([e].[Name]) AS int)
+FROM [Entity] AS [e]

tests/EntityFrameworkCore.Projectables.FunctionalTests/NullConditionals/RewriteNullConditionalRewriteTests.RelationalExpression.verified.txt

@@ -0,0 +1,5 @@
+SELECT CAST(1 AS bit), [e].[Id], [e0].[Id], [e0].[EntityId], [e0].[Name], [e1].[Id], [e1].[EntityId], [e1].[Name]
+FROM [Entity] AS [e]
+LEFT JOIN [Entity] AS [e0] ON [e].[Id] = [e0].[EntityId]
+LEFT JOIN [Entity] AS [e1] ON [e].[Id] = [e1].[EntityId]
+ORDER BY [e].[Id], [e0].[Id]

tests/EntityFrameworkCore.Projectables.FunctionalTests/NullConditionals/RewriteNullConditionalRewriteTests.SimpleMemberExpression.verified.txt

@@ -0,0 +1,2 @@
+SELECT CAST(LEN([e].[Name]) AS int)
+FROM [Entity] AS [e]

tests/EntityFrameworkCore.Projectables.FunctionalTests/NullConditionals/RewriteNullConditionalRewriteTests.cs

@@ -0,0 +1,48 @@
+using System;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using EntityFrameworkCore.Projectables.FunctionalTests.Helpers;
+using Microsoft.EntityFrameworkCore;
+using VerifyXunit;
+using Xunit;
+
+namespace EntityFrameworkCore.Projectables.FunctionalTests.NullConditionals
+{
+    [UsesVerify]
+    public class RewriteNullConditionalRewriteTests
+    {
+        [Fact]
+        public Task SimpleMemberExpression()
+        {
+            using var dbContext = new SampleDbContext<Entity>();
+
+            var query = dbContext.Set<Entity>()
+                .Select(x => x.GetNameLengthRewriteNulls());
+
+            return Verifier.Verify(query.ToQueryString());
+        }
+
+        [Fact]
+        public Task ComplexMemberExpression()
+        {
+            using var dbContext = new SampleDbContext<Entity>();
+
+            var query = dbContext.Set<Entity>()
+                .Select(x => x.GetNameLengthRewriteNulls());
+
+            return Verifier.Verify(query.ToQueryString());
+        }
+
+        [Fact]
+        public Task RelationalExpression()
+        {
+            using var dbContext = new SampleDbContext<Entity>();
+
+            var query = dbContext.Set<Entity>()
+                .Select(x => x.GetFirstRelatedRewriteNulls());
+
+            return Verifier.Verify(query.ToQueryString());
+        }
+    }
+}