Including and/or excluding properties in graph comparison should honor the declared type

Src/FluentAssertions/Collections/GenericCollectionAssertions.cs

@@ -254,7 +254,7 @@ public AndConstraint<GenericCollectionAssertions<T>> OnlyHaveUniqueItems<TKey>(E
                     ? unordered.OrderBy(keySelector, comparer)
                     : unordered.OrderByDescending(keySelector, comparer);
 
-                var orderString = propertyExpression.GetMemberPath();
+                string orderString = propertyExpression.GetMemberPath().ToString();
                 orderString = orderString == "\"\"" ? string.Empty : " by " + orderString;
 
                 Execute.Assertion

Src/FluentAssertions/Common/ExpressionExtensions.cs

@@ -5,10 +5,11 @@
 using System.Reflection;
 
 using FluentAssertions.Equivalency;
+using FluentAssertions.Equivalency.Selection;
 
 namespace FluentAssertions.Common
 {
-    public static class ExpressionExtensions
+    internal static class ExpressionExtensions
     {
         public static SelectedMemberInfo GetSelectedMemberInfo<T, TValue>(this Expression<Func<T, TValue>> expression)
         {
@@ -79,9 +80,12 @@ public static class ExpressionExtensions
         }
 
         /// <summary>
-        /// Gets a dotted path of property names representing the property expression. E.g. Parent.Child.Sibling.Name.
+        /// Gets a dotted path of property names representing the property expression, including the declaring type.
         /// </summary>
-        public static string GetMemberPath<TDeclaringType, TPropertyType>(
+        /// <example>
+        /// E.g. Parent.Child.Sibling.Name.
+        /// </example>
+        public static MemberPath GetMemberPath<TDeclaringType, TPropertyType>(
             this Expression<Func<TDeclaringType, TPropertyType>> expression)
         {
             if (expression == null)
@@ -90,6 +94,7 @@ public static class ExpressionExtensions
             }
 
             var segments = new List<string>();
+            var declaringTypes = new List<Type>();
             Expression node = expression;
 
             var unsupportedExpressionMessage = $"Expression <{expression.Body}> cannot be used to select a member.";
@@ -113,6 +118,7 @@ public static class ExpressionExtensions
                         node = memberExpression.Expression;
 
                         segments.Add(memberExpression.Member.Name);
+                        declaringTypes.Add(memberExpression.Member.DeclaringType);
                         break;
 
                     case ExpressionType.ArrayIndex:
@@ -144,9 +150,13 @@ public static class ExpressionExtensions
                 }
             }
 
+            // If any members were accessed in the expression, the first one found is the last member.
+            Type declaringType = declaringTypes.FirstOrDefault( ) ?? typeof(TDeclaringType);
+
             string[] reversedSegments = segments.AsEnumerable().Reverse().ToArray();
             string segmentPath = string.Join(".", reversedSegments);
-            return segmentPath.Replace(".[", "[");
+
+            return new MemberPath(declaringType, segmentPath.Replace(".[", "["));
         }
 
         internal static string GetMethodName(Expression<Action> action)

Src/FluentAssertions/Common/MemberPath.cs

@@ -0,0 +1,62 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace FluentAssertions.Common
+{
+    /// <summary>
+    /// Encapsulates a dotted candidate to a (nested) member of a type as well as the
+    /// declaring type of the deepest member.
+    /// </summary>
+    internal class MemberPath
+    {
+        private readonly Type declaringType;
+        private readonly string dottedPath;
+        private readonly List<string> segments = new List<string>();
+
+        public MemberPath(Type declaringType, string dottedPath)
+        {
+            this.declaringType = declaringType;
+            this.dottedPath = dottedPath;
+            segments.AddRange(Segmentize(dottedPath));
+        }
+
+        public bool IsParentOrChildOf(string candidate)
+        {
+            return IsParent(candidate) || IsChild(candidate);
+        }
+
+        public bool IsSameAs(string candidate, Type memberDeclaringType)
+        {
+            string[] candidateSegments = Segmentize(candidate);
+
+            return memberDeclaringType == declaringType && candidateSegments.SequenceEqual(segments);
+        }
+
+        private bool IsChild(string candidate)
+        {
+            string[] candidateSegments = Segmentize(candidate);
+
+            return candidateSegments.Length > segments.Count &&
+                   candidateSegments.Take(segments.Count).SequenceEqual(segments);
+        }
+
+        private bool IsParent(string candidate)
+        {
+            string[] candidateSegments = Segmentize(candidate);
+
+            return candidateSegments.Length < segments.Count
+                   && candidateSegments.SequenceEqual(segments.Take(candidateSegments.Length));
+        }
+
+        private static string[] Segmentize(string dottedPath)
+        {
+            return dottedPath.Split(new[] { '.', '[', ']' }, StringSplitOptions.RemoveEmptyEntries);
+        }
+
+        public override string ToString()
+        {
+            return dottedPath;
+        }
+    }
+}

Src/FluentAssertions/Common/StringExtensions.cs

@@ -5,15 +5,6 @@ namespace FluentAssertions.Common
 {
     internal static class StringExtensions
     {
-        /// <summary>
-        /// Finds the first index at which the <paramref name="value"/> does not match the <paramref name="expected"/>
-        /// string anymore, including the exact casing.
-        /// </summary>
-        public static int IndexOfFirstMismatch(this string value, string expected)
-        {
-            return IndexOfFirstMismatch(value, expected, StringComparison.CurrentCulture);
-        }
-
         /// <summary>
         /// Finds the first index at which the <paramref name="value"/> does not match the <paramref name="expected"/>
         /// string anymore, accounting for the specified <paramref name="stringComparison"/>.

Src/FluentAssertions/Equivalency/EquivalencyAssertionOptions.cs

@@ -68,7 +68,7 @@ public EquivalencyAssertionOptions<TExpectation> Including(Expression<Func<IMemb
         public EquivalencyAssertionOptions<TExpectation> WithStrictOrderingFor(
             Expression<Func<TExpectation, object>> expression)
         {
-            string expressionMemberPath = expression.GetMemberPath();
+            string expressionMemberPath = expression.GetMemberPath().ToString();
             orderingRules.Add(new PathBasedOrderingRule(expressionMemberPath));
             return this;
         }

Src/FluentAssertions/Equivalency/Selection/ExcludeMemberByPathSelectionRule.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using FluentAssertions.Common;
@@ -9,23 +10,25 @@ namespace FluentAssertions.Equivalency.Selection
     /// </summary>
     internal class ExcludeMemberByPathSelectionRule : SelectMemberByPathSelectionRule
     {
-        private readonly string pathToExclude;
+        private readonly MemberPath memberToExclude;
 
-        public ExcludeMemberByPathSelectionRule(string pathToExclude)
-            : base(pathToExclude)
+        public ExcludeMemberByPathSelectionRule(MemberPath pathToExclude)
+            : base(pathToExclude.ToString())
         {
-            this.pathToExclude = pathToExclude;
+            this.memberToExclude = pathToExclude;
         }
 
         protected override IEnumerable<SelectedMemberInfo> OnSelectMembers(IEnumerable<SelectedMemberInfo> selectedMembers,
             string currentPath, IMemberInfo context)
         {
-            return selectedMembers.Where(memberInfo => currentPath.Combine(memberInfo.Name) != pathToExclude).ToArray();
+            return selectedMembers
+                .Where(memberInfo => !memberToExclude.IsSameAs(currentPath.Combine(memberInfo.Name), memberInfo.DeclaringType))
+                .ToArray();
         }
 
         public override string ToString()
         {
-            return "Exclude member root." + pathToExclude;
+            return "Exclude member root." + memberToExclude;
         }
     }
 }

Src/FluentAssertions/Equivalency/Selection/IncludeMemberByPathSelectionRule.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using FluentAssertions.Common;
@@ -9,12 +10,12 @@ namespace FluentAssertions.Equivalency.Selection
     /// </summary>
     internal class IncludeMemberByPathSelectionRule : SelectMemberByPathSelectionRule
     {
-        private readonly MemberPath pathToInclude;
+        private readonly MemberPath memberToInclude;
 
-        public IncludeMemberByPathSelectionRule(string pathToInclude)
-            : base(pathToInclude)
+        public IncludeMemberByPathSelectionRule(MemberPath pathToInclude)
+            : base(pathToInclude.ToString())
         {
-            this.pathToInclude = new MemberPath(pathToInclude);
+            memberToInclude = pathToInclude;
         }
 
         public override bool IncludesMembers => true;
@@ -24,15 +25,17 @@ public IncludeMemberByPathSelectionRule(string pathToInclude)
         {
             var matchingMembers =
                 from member in context.RuntimeType.GetNonPrivateMembers()
-                where pathToInclude.IsParentOrChildOf(currentPath.Combine(member.Name))
+                let memberPath = currentPath.Combine(member.Name)
+                where memberToInclude.IsSameAs(memberPath, member.DeclaringType) ||
+                    memberToInclude.IsParentOrChildOf(memberPath)
                 select member;
 
             return selectedMembers.Concat(matchingMembers).ToArray();
         }
 
         public override string ToString()
         {
-            return "Include member root." + pathToInclude;
+            return "Include member root." + memberToInclude;
         }
     }
 }

Tests/Shared.Specs/BasicEquivalencySpecs.cs

@@ -1191,6 +1191,51 @@ public void When_a_property_is_hidden_in_a_derived_class_it_should_ignore_it()
             action.Should().NotThrow();
         }
 
+        [Fact]
+        public void When_including_a_property_that_is_hidden_in_a_derived_class_it_should_select_the_correct_one()
+        {
+            //-----------------------------------------------------------------------------------------------------------
+            // Arrange
+            //-----------------------------------------------------------------------------------------------------------
+            var b1 = new ClassThatHidesBaseClassProperty();
+            var b2 = new ClassThatHidesBaseClassProperty();
+
+            //-----------------------------------------------------------------------------------------------------------
+            // Act / Assert
+            //-----------------------------------------------------------------------------------------------------------
+            b1.Should().BeEquivalentTo(b2, config => config.Including(b => b.Property));
+        }
+
+        [Fact]
+        public void When_excluding_a_property_that_is_hidden_in_a_derived_class_it_should_select_the_correct_one()
+        {
+            //-----------------------------------------------------------------------------------------------------------
+            // Arrange
+            //-----------------------------------------------------------------------------------------------------------
+            var b1 = new ClassThatHidesBaseClassProperty();
+            var b2 = new ClassThatHidesBaseClassProperty();
+
+            //-----------------------------------------------------------------------------------------------------------
+            // Act
+            //-----------------------------------------------------------------------------------------------------------
+            Action act = () => b1.Should().BeEquivalentTo(b2, config => config.Excluding(b => b.Property));
+
+            //-----------------------------------------------------------------------------------------------------------
+            // Assert
+            //-----------------------------------------------------------------------------------------------------------
+            act.Should().Throw<XunitException>().WithMessage("Expected member Property*-*-*-*-*but*");
+        }
+
+        class ClassWithGuidProperty
+        {
+            public string Property { get; set; } = Guid.NewGuid().ToString();
+        }
+
+        class ClassThatHidesBaseClassProperty: ClassWithGuidProperty
+        {
+            public new string[] Property { get; set; }
+        }
+
         [Fact]
         public void When_a_property_is_an_indexer_it_should_be_ignored()
         {