- allow map to target without default constructor (sp thx to Burgyn)

- throw when pass nest destination member access to Map method

Author: chaowlert

src/Mapster.Tests/WhenUsingNonDefaultConstructor.cs

@@ -73,7 +73,7 @@ public void Map_To_Existing_Destination_Instance_Should_Pass()
         }
 
         [TestMethod]
-        public void Map_To_Destination_Type_Without_Default_Constructor_Shoud_Throw_Argument_Exception()
+        public void Map_To_Destination_Type_Without_Default_Constructor_Shoud_Throw_Exception()
         {
             var simplePoco = new SimplePoco { Id = Guid.NewGuid(), Name = "TestName" };
 
@@ -83,7 +83,7 @@ public void Map_To_Destination_Type_Without_Default_Constructor_Shoud_Throw_Argu
             };
 
             action.ShouldThrow<CompileException>()
-                .InnerException.ShouldBeOfType<ArgumentException>();
+                .InnerException.ShouldBeOfType<InvalidOperationException>();
         }
 
         #region TestClasses

src/Mapster/Adapters/BaseAdapter.cs

@@ -272,21 +272,30 @@ protected Expression CreateInstantiationExpression(Expression source, CompileArg
         protected virtual Expression CreateInstantiationExpression(Expression source, Expression destination, CompileArgument arg)
         {
             //new TDestination()
+
+            //if there is constructUsing, use constructUsing
             var constructUsing = arg.Settings.ConstructUsingFactory?.Invoke(arg);
             Expression newObj;
             if (constructUsing != null)
                 newObj = constructUsing.Apply(source).TrimConversion(true).To(arg.DestinationType);
-            else if (arg.DestinationType.GetTypeInfo().IsAbstract && arg.Settings.Includes.Count > 0)
+
+            //if there is default constructor, use default constructor
+            else if (arg.DestinationType.HasDefaultConstructor())
+                newObj = Expression.New(arg.DestinationType);
+
+            //if mapToTarget or include derived types, allow mapping & throw exception on runtime
+            //instantiation is not needed
+            else if (destination != null || arg.Settings.Includes.Count > 0)
                 newObj = Expression.Throw(
                     Expression.New(
                         // ReSharper disable once AssignNullToNotNullAttribute
                         typeof(InvalidOperationException).GetConstructor(new[] { typeof(string) }),
-                        Expression.Constant("Cannot instantiate abstract type: " + arg.DestinationType.Name)),
+                        Expression.Constant("Cannot instantiate type: " + arg.DestinationType.Name)),
                     arg.DestinationType);
-            else if (destination == null || arg.DestinationType.HasDefaultConstructor())
-                newObj = Expression.New(arg.DestinationType);
+
+            //otherwise throw
             else
-                newObj = destination;
+                throw new InvalidOperationException($"No default constructor for type '{arg.DestinationType.Name}', please use 'ConstructUsing'");
 
             //dest ?? new TDest();
             return destination == null

src/Mapster/Extensions.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Linq;
 using System.Linq.Expressions;
+using System.Reflection;
 using Mapster.Models;
 
 namespace Mapster
@@ -22,7 +23,7 @@ public static bool HasCustomAttribute(this IMemberModel member, Type type)
 
         public static T GetCustomAttribute<T>(this IMemberModel member)
         {
-            return (T)member.GetCustomAttributes(true).FirstOrDefault(attr => attr is T);
+            return (T) member.GetCustomAttributes(true).FirstOrDefault(attr => attr is T);
         }
 
         /// <summary>
@@ -33,7 +34,15 @@ public static T GetCustomAttribute<T>(this IMemberModel member)
         ///   <c>true</c> if specific <paramref name="type"/> has default constructor; otherwise <c>false</c>.
         /// </returns>
         public static bool HasDefaultConstructor(this Type type)
-            => type.IsValueType || type.GetConstructor(Type.EmptyTypes) != null;
+        {
+            if (type == typeof(void)
+                || type.GetTypeInfo().IsAbstract
+                || type.GetTypeInfo().IsInterface)
+                return false;
+            if (type.GetTypeInfo().IsValueType)
+                return true;
+            return type.GetConstructor(Type.EmptyTypes) != null;
+        }
 
     }
 }

src/Mapster/Mapster.NetCore.csproj

@@ -12,8 +12,8 @@
     <PackageId>Mapster</PackageId>
     <PackageTags>Mapper;AutoMapper;Fast;Mapping</PackageTags>
     <PackageIconUrl>https://cloud.githubusercontent.com/assets/5763993/26522718/d16f3e42-4330-11e7-9b78-f8c7402624e7.png</PackageIconUrl>
-    <PackageProjectUrl>https://github.com/chaowlert/Mapster</PackageProjectUrl>
-    <PackageLicenseUrl>https://github.com/chaowlert/Mapster/blob/master/LICENSE</PackageLicenseUrl>
+    <PackageProjectUrl>https://github.com/MapsterMapper/Mapster</PackageProjectUrl>
+    <PackageLicenseUrl>https://github.com/MapsterMapper/Mapster/blob/master/LICENSE</PackageLicenseUrl>
     <NetStandardImplicitPackageVersion Condition=" '$(TargetFramework)' == 'netstandard1.3' ">1.6.0</NetStandardImplicitPackageVersion>
     <GenerateAssemblyTitleAttribute>false</GenerateAssemblyTitleAttribute>
     <GenerateAssemblyDescriptionAttribute>false</GenerateAssemblyDescriptionAttribute>
@@ -22,7 +22,7 @@
     <GenerateAssemblyProductAttribute>false</GenerateAssemblyProductAttribute>
     <GenerateAssemblyCopyrightAttribute>false</GenerateAssemblyCopyrightAttribute>
     <GeneratePackageOnBuild>True</GeneratePackageOnBuild>
-    <Version>3.1.6</Version>
+    <Version>3.1.7</Version>
     <RootNamespace>Mapster</RootNamespace>
   </PropertyGroup>
 

src/Mapster/Utils/ReflectionUtils.cs

@@ -128,26 +128,28 @@ public static Type UnwrapNullable(this Type type)
             return type.IsNullable() ? type.GetGenericArguments()[0] : type;
         }
 
-        public static MemberExpression GetMemberInfo(Expression method, bool noThrow = false)
+        public static MemberExpression GetMemberInfo(Expression member, bool source = false)
         {
-            var lambda = method as LambdaExpression;
+            var lambda = member as LambdaExpression;
             if (lambda == null)
-                throw new ArgumentNullException(nameof(method));
-
-            MemberExpression memberExpr = null;
+                throw new ArgumentNullException(nameof(member));
 
+            var expr = lambda.Body;
             if (lambda.Body.NodeType == ExpressionType.Convert)
+                expr = ((UnaryExpression)lambda.Body).Operand;
+
+            MemberExpression memberExpr = null;
+            if (expr.NodeType == ExpressionType.MemberAccess)
             {
-                memberExpr =
-                    ((UnaryExpression) lambda.Body).Operand as MemberExpression;
-            }
-            else if (lambda.Body.NodeType == ExpressionType.MemberAccess)
-            {
-                memberExpr = lambda.Body as MemberExpression;
+                var tmp = (MemberExpression) expr;
+                if (tmp.Expression.NodeType == ExpressionType.Parameter)
+                    memberExpr = tmp;
+                else if (!source)
+                    throw new ArgumentException("Only first level member access on destination allowed (eg. dest => dest.Name)", nameof(member));
             }
 
-            if (memberExpr == null && !noThrow)
-                throw new ArgumentException("argument must be member access", nameof(method));
+            if (memberExpr == null && !source)
+                throw new ArgumentException("Argument must be member access", nameof(member));
 
             return memberExpr;
         }