Add support for querying dynamic objects with Linq

Author: hazzik

src/NHibernate.Test/NHSpecificTest/NH2664Dynamic/Fixture.cs

@@ -0,0 +1,103 @@
+using System.Collections;
+using System.Linq;
+using NUnit.Framework;
+using System.Collections.Generic;
+using System.Linq.Dynamic.Core;
+
+namespace NHibernate.Test.NHSpecificTest.NH2664Dynamic
+{
+	[TestFixture]
+	public class Fixture : TestCase
+	{
+		protected override string MappingsAssembly => "NHibernate.Test";
+
+		protected override IList Mappings => new[] {"NHSpecificTest.NH2664Dynamic.Mappings.hbm.xml"};
+
+		/// <summary>
+		/// push some data into the database
+		/// Really functions as a save test also 
+		/// </summary>
+		protected override void OnSetUp()
+		{
+			using (var session = OpenSession())
+			using (var tran = session.BeginTransaction())
+			{
+				session.Save(
+					new Product
+					{
+						ProductId = "1",
+						Properties = new Dictionary<string, object>
+						{
+							["Name"] = "First Product",
+							["Description"] = "First Description"
+						}
+					});
+
+				session.Save(
+					new Product
+					{
+						ProductId = "2",
+						Properties = new Dictionary<string, object>
+						{
+							["Name"] = "Second Product",
+							["Description"] = "Second Description"
+						}
+					});
+
+				session.Save(
+					new Product
+					{
+						ProductId = "3",
+						Properties = new Dictionary<string, object>
+						{
+							["Name"] = "val",
+							["Description"] = "val"
+						}
+					});
+
+				tran.Commit();
+			}
+		}
+
+		protected override void OnTearDown()
+		{
+			using (var session = OpenSession())
+			using (var tran = session.BeginTransaction())
+			{
+				session.CreateQuery("delete from Product").ExecuteUpdate();
+				tran.Commit();
+			}
+		}
+
+		[Test]
+		public void Query_DynamicComponent()
+		{
+			using (var session = OpenSession())
+			{
+				var product = session
+				              .Query<Product>()
+				              .Where("Properties.Name == @0", "First Product")
+				              .Single();
+
+				Assert.That(product, Is.Not.Null);
+				Assert.That((object) product.Properties["Name"], Is.EqualTo("First Product"));
+			}
+		}
+
+		[Test]
+		public void Multiple_Query_Does_Not_Cache()
+		{
+			using (var session = OpenSession())
+			{
+				// Query by name
+				var product1 = session.Query<Product>().Where("Properties.Name == @0", "First Product").Single();
+				Assert.That(product1.ProductId, Is.EqualTo("1"));
+
+				// Query by description (this test is to verify that the dictionary
+				// index isn't cached from the query above.
+				var product2 = session.Query<Product>().Where("Properties.Description == @0", "Second Description").Single();
+				Assert.That(product2.ProductId, Is.EqualTo("2"));
+			}
+		}
+	}
+}

src/NHibernate.Test/NHSpecificTest/NH2664Dynamic/Mappings.hbm.xml

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" assembly="NHibernate.Test"
+                   namespace="NHibernate.Test.NHSpecificTest.NH2664Dynamic">
+	<class name="Product" table="Products">
+		<id name="ProductId" column="ProductId" type="String">
+			<generator class="assigned" />
+
+		</id>
+		<dynamic-component name="Properties">
+			<property name="Description" column="Description" type="String"/>
+			<property name="Name" column="Name" type="String" />
+
+		</dynamic-component>
+
+	</class>
+
+</hibernate-mapping>

src/NHibernate.Test/NHSpecificTest/NH2664Dynamic/Product.cs

@@ -0,0 +1,9 @@
+namespace NHibernate.Test.NHSpecificTest.NH2664Dynamic
+{
+	public class Product
+	{
+		public virtual string ProductId { get; set; }
+
+		public virtual dynamic Properties { get; set; }
+	}
+}

src/NHibernate.Test/NHibernate.Test.csproj

@@ -48,7 +48,7 @@
   </ItemGroup>
   <ItemGroup>
     <PackageReference Include="log4net" Version="2.0.8" />
-    <PackageReference Include="System.Linq.Dynamic.Core" Version="1.0.8" />
+    <PackageReference Include="System.Linq.Dynamic.Core" Version="1.0.8.11" />
     <PackageReference Include="NSubstitute" Version="3.1.0" />
     <PackageReference Include="NUnit" Version="3.10.1" />
     <PackageReference Include="NUnit3TestAdapter" Version="3.10.0" />

src/NHibernate/Linq/Visitors/HqlGeneratorExpressionVisitor.cs

@@ -1,6 +1,8 @@
 using System;
+using System.Dynamic;
 using System.Linq;
 using System.Linq.Expressions;
+using System.Runtime.CompilerServices;
 using NHibernate.Engine.Query;
 using NHibernate.Hql.Ast;
 using NHibernate.Linq.Expressions;
@@ -141,7 +143,6 @@ protected HqlTreeNode VisitExpression(Expression expression)
 			}
 		}
 
-
 		private HqlTreeNode VisitTypeBinaryExpression(TypeBinaryExpression expression)
 		{
 			return BuildOfType(expression.Expression, expression.TypeOperand);
@@ -206,6 +207,18 @@ private HqlTreeNode VisitNhNominated(NhNominatedExpression nhNominatedExpression
 
 		private HqlTreeNode VisitInvocationExpression(InvocationExpression expression)
 		{
+			//This is an ugly workaround for dynamic expressions.
+			//Unfortunately we can not tap into the expression tree earlier to intercept the dynamic expression
+			if (expression.Arguments.Count == 2 &&
+			    expression.Arguments[0] is ConstantExpression constant &&
+			    constant.Value is CallSite site &&
+			    site.Binder is GetMemberBinder binder)
+			{
+				return _hqlTreeBuilder.Dot(
+					VisitExpression(expression.Arguments[1]).AsExpression(),
+					_hqlTreeBuilder.Ident(binder.Name));
+			}
+
 			return VisitExpression(expression.Expression);
 		}