Merge pull request #3405 from lbargaoanu/cycles

Improve cycle detection with inheritance

Author: jbogard

src/AutoMapper/Execution/TypeMapPlanBuilder.cs

@@ -79,7 +79,9 @@ private void CheckForCycles(HashSet<TypeMap> typeMapsPath)
             }
             typeMapsPath.Add(_typeMap);
             var members = 
-                _typeMap.MemberMaps.Where(pm=>pm.CanResolveValue)
+                _typeMap.MemberMaps
+                .Concat(_typeMap.IncludedDerivedTypes.Select(ResolveTypeMap).SelectMany(tm=>tm.MemberMaps))
+                .Where(pm=>pm.CanResolveValue)
                 .ToArray()
                 .Select(pm=> new { MemberTypeMap = ResolveMemberTypeMap(pm), MemberMap = pm })
                 .Where(p => p.MemberTypeMap != null && !p.MemberTypeMap.PreserveReferences && p.MemberTypeMap.MapExpression == null);
@@ -103,7 +105,6 @@ private void CheckForCycles(HashSet<TypeMap> typeMapsPath)
                         typeMapsPath.Remove(_typeMap);
                         return;
                     }
-
                     SetPreserveReferences(memberTypeMap);
                     foreach(var derivedTypeMap in memberTypeMap.IncludedDerivedTypes.Select(ResolveTypeMap))
                     {
@@ -123,7 +124,7 @@ void SetPreserveReferences(TypeMap memberTypeMap)
 
             TypeMap ResolveMemberTypeMap(IMemberMap memberMap)
             {
-                if(memberMap.SourceType == null)
+                if(memberMap.SourceType == null || memberMap.Types.ContainsGenericParameters)
                 {
                     return null;
                 }

src/AutoMapper/TypePair.cs

@@ -92,6 +92,8 @@ public static TypePair Create<TSource, TDestination>(TSource source, TDestinatio
 
         public bool IsGenericTypeDefinition => SourceType.IsGenericTypeDefinition || DestinationType.IsGenericTypeDefinition;
 
+        public bool ContainsGenericParameters => SourceType.ContainsGenericParameters || DestinationType.ContainsGenericParameters;
+
         public TypePair? GetOpenGenericTypePair()
         {
             if(!IsGeneric)

src/UnitTests/BidirectionalRelationshipsWithoutPR.cs

@@ -1,11 +1,70 @@
 using System;
+using System.CodeDom;
 using System.Collections.Generic;
 using System.Linq;
 using Shouldly;
 using Xunit;
 
 namespace AutoMapper.UnitTests
 {
+    public class CyclesWithInheritance : AutoMapperSpecBase
+    {
+        class FlowChart
+        {
+            public FlowNode[] Nodes;
+        }
+        class FlowNode
+        {
+        }
+        class FlowStep : FlowNode
+        {
+            public FlowNode Next;
+        }
+        class FlowDecision : FlowNode
+        {
+            public FlowNode True;
+            public FlowNode False;
+        }
+        class FlowSwitch<T> : FlowNode
+        {
+            public IDictionary<T, object> Connections;
+        }
+        class FlowChartModel
+        {
+            public FlowNodeModel[] Nodes;
+        }
+        class FlowNodeModel
+        {
+            public Connection[] Connections;
+        }
+        class Connection
+        {
+            public FlowNodeModel Node;
+        }
+        protected override MapperConfiguration Configuration => new MapperConfiguration(cfg=>
+        {
+            cfg.CreateMap<FlowChart, FlowChartModel>();
+            cfg.CreateMap<FlowNode, FlowNodeModel>()
+                .Include<FlowStep, FlowNodeModel>()
+                .Include<FlowDecision, FlowNodeModel>()
+                .Include(typeof(FlowSwitch<>), typeof(FlowNodeModel))
+                .ForMember(d=>d.Connections, o=>o.Ignore());
+            cfg.CreateMap<FlowStep, FlowNodeModel>().ForMember(d => d.Connections, o => o.MapFrom(s => new[] { s.Next }));
+            cfg.CreateMap<FlowDecision, FlowNodeModel>().ForMember(d => d.Connections, o => o.MapFrom(s => new[] { s.True, s.False }));
+            cfg.CreateMap(typeof(FlowSwitch<>), typeof(FlowNodeModel));
+            cfg.CreateMap<FlowNode, Connection>().ForMember(d => d.Node, o => o.MapFrom(s => s));
+            cfg.CreateMap(typeof(KeyValuePair<,>), typeof(Connection)).ForMember("Node", o => o.MapFrom("Key"));
+        });
+        [Fact]
+        public void Should_map_ok()
+        {
+            var flowStep = new FlowStep();
+            var flowDecision = new FlowDecision { False = flowStep, True = flowStep };
+            flowStep.Next = flowDecision;
+            var source = new FlowChart { Nodes = new FlowNode[] { flowStep, flowDecision } };
+            var dest = Map<FlowChartModel>(source);
+        }
+    }
     public class When_the_source_has_cyclical_references_with_dynamic_map : AutoMapperSpecBase
     {
         public class CDataTypeModel<T>