Adding coarse lock to inline map creation; restoring cache

src/AutoMapper/Configuration/Conventions/SourceToDestinationNameMapperAttributesMember.cs

@@ -1,18 +1,22 @@
 using System;
+using System.Collections.Generic;
 using System.Linq;
 using System.Reflection;
 
 namespace AutoMapper.Configuration.Conventions
 {
     public class SourceToDestinationNameMapperAttributesMember : ISourceToDestinationNameMapper
     {
+        private static readonly SourceMember[] Empty = new SourceMember[0];
+        private readonly Dictionary<TypeDetails, SourceMember[]> _allSourceMembers = new Dictionary<TypeDetails, SourceMember[]>();
+
         public MemberInfo GetMatchingMemberInfo(IGetTypeInfoMembers getTypeInfoMembers, TypeDetails typeInfo, Type destType, Type destMemberType, string nameToSearch)
         {
-            var sourceMembers = getTypeInfoMembers.GetMemberInfos(typeInfo)
-                .Select(sourceMember => new SourceMember(sourceMember))
-                .Where(s => s.Attribute != null)
-                .ToArray();
-
+            if (!_allSourceMembers.TryGetValue(typeInfo, out SourceMember[] sourceMembers))
+            {
+                sourceMembers = getTypeInfoMembers.GetMemberInfos(typeInfo).Select(sourceMember => new SourceMember(sourceMember)).Where(s => s.Attribute != null).ToArray();
+                _allSourceMembers[typeInfo] = sourceMembers.Length == 0 ? Empty : sourceMembers;
+            }
             return sourceMembers.FirstOrDefault(d => d.Attribute.IsMatch(typeInfo, d.Member, destType, destMemberType, nameToSearch)).Member;
         }
 

src/AutoMapper/MapperConfiguration.cs

@@ -254,7 +254,10 @@ private TypeMap GetTypeMap(TypePair initialTypes)
                 && !ExcludedTypes.Contains(initialTypes.SourceType)
                 && !ExcludedTypes.Contains(initialTypes.DestinationType))
             {
-                return Configuration.CreateInlineMap(_typeMapRegistry, initialTypes);
+                lock (this)
+                {
+                    return Configuration.CreateInlineMap(_typeMapRegistry, initialTypes);
+                }
             }
 
             return null;