writability of ExpressionToProperty is checked during mapper building

src/EntityFunctors/Associations/Impl/ExpressionToPropertyAssociation.cs

@@ -7,7 +7,7 @@
     using EntityFunctors.Extensions;
     using EntityFunctors.Associations.Fluent;
 
-    public class ExpressionToPropertyAssociation<TSource, TTarget, TProperty> 
+    public class ExpressionToPropertyAssociation<TSource, TTarget, TProperty>
         : IMappingAssociation, IAccessable
         where TSource : class
         where TTarget : class, new()
@@ -24,11 +24,13 @@ public ExpressionToPropertyAssociation(Expression<Func<TSource, TProperty>> sour
         {
             Contract.Assert(source != null);
             Contract.Assert(target != null);
-            Contract.Assert(source.ReturnType == target.ReturnType);
-
+
             PropertyInfo prop;
             Contract.Assert(target.Body.TryGetProperty(out prop));
 
+            if (source.Body is MemberExpression && (source.Body as MemberExpression).Expression == source.Parameters[0])
+                throw new ArgumentException("ExpressionToProperty association cannot be used for mapping properties");
+
             Source = source;
             Target = target;
 
@@ -44,9 +46,6 @@ public void ReadOnly()
 
         public void WriteOnly()
         {
-            if (!IsPropertyChain(Source))
-                throw new InvalidOperationException("Only property chain expression can be set writable");
-
             Direction = MappingDirection.Write;
         }
 
@@ -57,9 +56,6 @@ public void Read()
 
         public void Write()
         {
-            if (!IsPropertyChain(Source))
-                throw new InvalidOperationException("Only property chain expression can be set writable");
-
             AddDirection(MappingDirection.Write);
         }
 
@@ -68,25 +64,5 @@ private void AddDirection(MappingDirection val)
             if ((Direction & val) != val)
                 Direction |= val;
         }
-
-        private bool IsPropertyChain(LambdaExpression expression)
-        {
-            var current = expression.Body;
-
-            while (current != null)
-            {
-                PropertyInfo p;
-
-                if (current.NodeType == ExpressionType.Parameter)
-                    return true;
-
-                if (!current.TryGetProperty(out p))
-                    return false;
-
-                current = (current as MemberExpression).Expression;
-            }
-
-            return true;
-        }
     }
 }

src/EntityFunctors/Cfg/Config.cs

@@ -2,11 +2,12 @@ namespace EntityFunctors.Cfg
 {
     public static class Config
     {
-        private static IReflectionOptimizer _reflectionOptimizer { get; set; }
+        private static IReflectionOptimizer _reflectionOptimizer;
 
         public static IReflectionOptimizer ReflectionOptimizer
         {
             get { return _reflectionOptimizer ?? (_reflectionOptimizer = new DefaultReflectionOptimizer()); }
+			set { _reflectionOptimizer = value; }
         }
     }
 }

src/EntityFunctors/Mappers/MapperFactory.cs

@@ -41,11 +41,6 @@ public MapperFactory(params IAssociationProvider[] maps)
 
         public MapperFactory(IEnumerable<IAssociationProvider> providers)
         {
-            providers.ToDictionary(
-                m => m.Key,
-                m => m.Associations
-                );
-
             _registry = providers.ToDictionary(p => p.Key, p => p.Associations);
         }
 
@@ -80,7 +75,7 @@ private Expression BuildReaderBody(Expression @from, Type targetType, ParameterE
             IEnumerable<IMappingAssociation> associations;
 
             if (!_registry.TryGetValue(mapKey, out associations))
-                throw new NotImplementedException(
+                throw new InvalidOperationException(
                     string.Format("Unable to create mapper from {0} to {1}. Check appropriate mappings exist and loaded.", from.Type, targetType)
                 );
 
@@ -231,7 +226,7 @@ private Expression BuildWriterBody(Expression from, Expression to, ParameterExpr
             IEnumerable<IMappingAssociation> associations;
 
             if (!_registry.TryGetValue(mapKey, out associations))
-                throw new NotImplementedException(
+                throw new InvalidOperationException(
                     string.Format("Unable to create mapper from {0} to {1}. Check appropriate mappings exist and loaded.", @from.Type, to.Type)
                     );
 
@@ -274,6 +269,12 @@ private Expression BuildWriterItem(IMappingAssociation association, Expression f
             }
             else
             {
+                PropertyInfo prop;
+                if (!acceptor.TryGetProperty(out prop))
+                    throw new InvalidOperationException(
+                        string.Format("Mapping from source:{0} to target:{1} marked as writable but source is not a property access expression", association.Source.Stringify(), association.Target.Stringify())
+                    );
+
                 result = Expression.Assign(
                     acceptor, 
                     converter == null ? donor : converter.TargetConverter.Expression.Apply(donor)

src/EntityFunctors/TypeMap.cs

@@ -9,8 +9,8 @@
     using Associations.Impl;
     using Extensions;
 
-    public class TypeMap<TSource, TTarget> : IAssociationProvider 
-        where TSource : class 
+    public class TypeMap<TSource, TTarget> : IAssociationProvider
+        where TSource : class
         where TTarget : class, new()
     {
         private readonly IList<IMappingAssociation> _associations = new List<IMappingAssociation>();
@@ -33,9 +33,9 @@ Expression<Func<TTarget, TProperty>> target
         }
 
         protected IAccessable MapProperties<TSourceProperty, TTargetProperty>(
-            Expression<Func<TSource, TSourceProperty>> source, 
-            Expression<Func<TSourceProperty, TTargetProperty>> converter, 
-            Expression<Func<TTarget, TTargetProperty>> target, 
+            Expression<Func<TSource, TSourceProperty>> source,
+            Expression<Func<TSourceProperty, TTargetProperty>> converter,
+            Expression<Func<TTarget, TTargetProperty>> target,
             Expression<Func<TTargetProperty, TSourceProperty>> inverseConverter
         )
         {
@@ -47,7 +47,7 @@ Expression<Func<TTargetProperty, TSourceProperty>> inverseConverter
             return association;
         }
 
-        protected void MapExpressionToProperty<TProperty>(
+        protected IAccessable MapExpressionToProperty<TProperty>(
             Expression<Func<TSource, TProperty>> source,
             Expression<Func<TTarget, TProperty>> target
         )
@@ -56,13 +56,14 @@ Expression<Func<TTarget, TProperty>> target
 
             var association = new ExpressionToPropertyAssociation<TSource, TTarget, TProperty>(source, target);
             _associations.Add(association);
+            return association;
         }
 
         protected IExpandable MapComponents<TSourceComponent, TTargetComponent>(
             Expression<Func<TSource, TSourceComponent>> source,
             Expression<Func<TTarget, TTargetComponent>> target
-        ) 
-            where TSourceComponent : class 
+        )
+            where TSourceComponent : class
             where TTargetComponent : class, new()
         {
             var association = new ComponentToComponentAssociation<TSource, TSourceComponent, TTarget, TTargetComponent>(source, target);
@@ -86,8 +87,8 @@ Expression<Func<TSourceItem, TTargetItem>> converter
         protected IExpandable MapComponentCollections<TSourceItem, TTargetItem>(
             Expression<Func<TSource, IEnumerable<TSourceItem>>> source,
             Expression<Func<TTarget, IEnumerable<TTargetItem>>> target
-        ) 
-            where TSourceItem : class 
+        )
+            where TSourceItem : class
             where TTargetItem : class, new()
         {
             var association = new ComponentCollectionAssociation<TSource, TSourceItem, TTarget, TTargetItem>(source, target);
@@ -96,7 +97,7 @@ Expression<Func<TTarget, IEnumerable<TTargetItem>>> target
         }
 
         public virtual TypeMapKey Key { get; protected set; }
-        
+
         public IEnumerable<IMappingAssociation> Associations
         {
             get { return _associations; }

test/EntityFunctors.Tests/ExpressionToPropertyAssociationTests.cs

@@ -58,16 +58,6 @@ public void TestInverseMappingDoesNothing()
             foo.Id.Should().Be(10);
         }
 
-        [Test]
-        public void TestSettingWritablityThrowsOnInappropriateExpression()
-        {
-            Expression<Func<Foo, int>> source = _ => _.Id * _.Id;
-
-            var sut = new ExpressionToPropertyAssociation<Foo, Bar, int>(source, _ => _.Id);
-
-            ((Action) sut.Write).ShouldThrow<InvalidOperationException>();
-        }
-
         [Test]
         public void TestInverseMappingAssignsOnWrite()
         {