Merge branch 'develop' of https://github.com/txavier/DelegateDecompiler into txavier-develop

Author: hazzik

src/DelegateDecompiler.EntityFramework.Tests/DelegateDecompiler.EntityFramework.Tests.csproj

@@ -1,23 +1,23 @@
-<Project Sdk="Microsoft.NET.Sdk">
-  <Import Project="..\..\DelegateDecompiler.props" />
-
-  <PropertyGroup>
-    <TargetFramework>net45</TargetFramework>
-    <Copyright>Copyright © Dave Glick 2014, Jon Smith 2014, Alexander Zaytsev 2014 - 2017</Copyright>
-  </PropertyGroup>
-
-  <ItemGroup>
-    <PackageReference Include="nunit" Version="3.7.1" />
-  </ItemGroup>
-
-  <ItemGroup Condition="'$(TargetFramework)' != 'net40'">
-    <PackageReference Include="NUnit3TestAdapter" Version="3.8.0" />
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="15.3.0" />
-  </ItemGroup>
-
-  <ItemGroup>
-    <ProjectReference Include="..\DelegateDecompiler.EntityFramework\DelegateDecompiler.EntityFramework.csproj" />
-    <ProjectReference Include="..\DelegateDecompiler.Tests\DelegateDecompiler.Tests.csproj" />
-  </ItemGroup>
-
-</Project>
+<Project Sdk="Microsoft.NET.Sdk">
+  <Import Project="..\..\DelegateDecompiler.props" />
+
+  <PropertyGroup>
+    <TargetFramework>net45</TargetFramework>
+    <Copyright>Copyright © Dave Glick 2014, Jon Smith 2014, Alexander Zaytsev 2014 - 2017</Copyright>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="nunit" Version="3.7.1" />
+  </ItemGroup>
+
+  <ItemGroup Condition="'$(TargetFramework)' != 'net40'">
+    <PackageReference Include="NUnit3TestAdapter" Version="3.8.0" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="15.3.0" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\DelegateDecompiler.EntityFramework\DelegateDecompiler.EntityFramework.csproj" />
+    <ProjectReference Include="..\DelegateDecompiler.Tests\DelegateDecompiler.Tests.csproj" />
+  </ItemGroup>
+
+</Project>

src/DelegateDecompiler.EntityFramework.Tests/TestGroup20Relationship/Test01Include.cs

@@ -0,0 +1,44 @@
+// Contributed by @JonPSmith (GitHub) www.thereformedprogrammer.com
+
+using System.Linq;
+using DelegateDecompiler.EntityFramework.Tests.Helpers;
+using NUnit.Framework;
+using DelegateDecompiler.EntityFramework.Tests.EfItems;
+using System.Data.Entity;
+using System.Collections.Generic;
+
+namespace DelegateDecompiler.EntityFramework.Tests.TestGroup05BasicFeatures
+{
+    class Test01Include
+    {
+        private ClassEnvironment classEnv;
+
+        [OneTimeSetUp]
+        public void SetUpFixture()
+        {
+            classEnv = new ClassEnvironment();
+        }
+
+        [Computed]
+        private static bool ComputedSample() { return true; }
+
+        [Test]
+        public void TestInclude()
+        {
+            using (var db = new EfTestDbContext())
+            using (var env = new MethodEnvironment(classEnv))
+            {
+                //SETUP
+                var linq = db.EfParents.Where(p => true).Include(p => p.Children).ToList();
+
+                //ATTEMPT
+                env.AboutToUseDelegateDecompiler();
+                var dd = env.Db.EfParents.Where(p => ComputedSample()).Include(p => p.Children).Decompile().ToList();
+
+                //VERIFY
+                env.CompareAndLogList(linq, dd);
+            }
+        }
+
+    }
+}

src/DelegateDecompiler/DecompileExpressionVisitor.cs

@@ -14,6 +14,50 @@ public static Expression Decompile(Expression expression)
             return new DecompileExpressionVisitor().Visit(expression);
         }
 
+        private static readonly object NULL = new object(); // for use as a dictionary key
+        private readonly Dictionary<object, Expression> visitedConstants;
+
+        private bool hasAnyChanges = false;
+        public override Expression Visit(Expression node)
+        {
+            var result = base.Visit(node);
+            if (result != node)
+                hasAnyChanges = true;
+            return result;
+        }
+
+        private DecompileExpressionVisitor(Dictionary<object, Expression> sharedVisitedConstants = null)
+        {
+            this.visitedConstants = sharedVisitedConstants ?? new Dictionary<object, Expression>();
+        }
+
+        protected override Expression VisitConstant(ConstantExpression node)
+        {
+            Expression result;
+            if (visitedConstants.TryGetValue(node.Value ?? NULL, out result))
+            {
+                return result; // avoid infinite recursion
+            }
+
+            if (typeof(IQueryable).IsAssignableFrom(node.Type))
+            {
+                visitedConstants.Add(node.Value ?? NULL, node);
+
+                var value = (IQueryable)node.Value;
+                var childVisitor = new DecompileExpressionVisitor(visitedConstants);
+                result = childVisitor.Visit(value.Expression);
+
+                if (childVisitor.hasAnyChanges)
+                {
+                    result = Expression.Constant(value.Provider.CreateQuery(result), node.Type);
+                    visitedConstants[node.Value ?? NULL] = result;
+                    return result;
+                }
+            }
+
+            return node;
+        }
+        
         protected override Expression VisitMember(MemberExpression node)
         {
             if (ShouldDecompile(node.Member))