Fix setting property with private setter on base type (#390)

* Fix setting property with private setter on base type

* Small refactoring: Breakup LINQ statement for debugability and better readability.

Co-authored-by: Thomas Levesque <[email protected]>
Co-authored-by: bchavez <[email protected]>

Author: thomaslevesque

Source/Bogus.Tests/GitHubIssues/Issue389.cs

@@ -0,0 +1,49 @@
+using FluentAssertions;
+using Xunit;
+
+namespace Bogus.Tests.GitHubIssues
+{
+   public class Issue389
+   {
+      [Fact]
+      public void property_with_private_setter_in_base_class_is_assigned()
+      {
+         var foo = new Faker<Foo>()
+           .RuleFor(f => f.PropInFoo, _ => 42)
+           .RuleFor(f => f.PropInFooBase, _ => 123)
+           .Generate();
+
+         foo.PropInFoo.Should().Be(42);
+         foo.PropInFooBase.Should().Be(123);
+      }
+
+      public class FooBase
+      {
+         public int PropInFooBase { get; private set; }
+      }
+
+      public class Foo : FooBase
+      {
+         public int PropInFoo { get; private set; }
+      }
+
+      public class Zoo : Foo
+      {
+         public int PropInZoo { get; private set; }
+      }
+
+      [Fact]
+      public void property_with_private_setter_inheritance_chain_is_assigned()
+      {
+         var zoo = new Faker<Zoo>()
+            .RuleFor(f => f.PropInFoo, _ => 42)
+            .RuleFor(f => f.PropInFooBase, _ => 123)
+            .RuleFor(f => f.PropInZoo, _ => 77)
+            .Generate();
+
+         zoo.PropInFoo.Should().Be(42);
+         zoo.PropInFooBase.Should().Be(123);
+         zoo.PropInZoo.Should().Be(77);
+      }
+   }
+}

Source/Bogus/Binder.cs

@@ -49,6 +49,7 @@ public Binder(BindingFlags bindingFlags)
       {
          BindingFlags = bindingFlags;
       }
+      
 
       /// <summary>
       /// Given T, the method will return a Dictionary[string,MemberInfo] where
@@ -60,27 +61,34 @@ public Binder(BindingFlags bindingFlags)
       /// <returns>The full set of MemberInfos for injection.</returns>
       public virtual Dictionary<string, MemberInfo> GetMembers(Type t)
       {
-         var group = t.GetAllMembers(BindingFlags)
+         var allReflectedMembers = t.GetAllMembers(this.BindingFlags)
+                                    .Select(m => UseBaseTypeDeclaredPropertyInfo(t, m));
+
+         var settableMembers = allReflectedMembers
             .Where(m =>
                {
                   if( m.GetCustomAttributes(typeof(CompilerGeneratedAttribute), true).Any() )
                   {
                      //no compiler generated stuff
                      return false;
                   }
+
                   if( m is PropertyInfo pi )
                   {
                      return pi.CanWrite;
                   }
+
                   if( m is FieldInfo fi )
                   {
                      //No private fields.
                      //GitHub Issue #13
                      return !fi.IsPrivate;
                   }
+
                   return false;
-               })
-            .GroupBy(mi => mi.Name);
+               });
+
+         var settableMembersByName = settableMembers.GroupBy(mi => mi.Name);
 
          //Issue #70 we could get back multiple keys
          //when reflecting over a type. Consider:
@@ -92,7 +100,22 @@ public virtual Dictionary<string, MemberInfo> GetMembers(Type t)
          //reflected MemberInfo that was returned from
          //reflection; the second one was the inherited
          //ClassA.Value.
-         return group.ToDictionary(k => k.Key, g => g.First());
+         return settableMembersByName.ToDictionary(k => k.Key, g => g.First());
+      }
+
+      //Issue #389 - Use Declaring Base Type PropertyInfo instead of a DerivedA's 
+      //PropertyInfo because DerivedA's PropertyInfo could say property is not
+      //write-able.
+      protected virtual MemberInfo UseBaseTypeDeclaredPropertyInfo(Type t, MemberInfo m)
+      {
+         if( m is PropertyInfo {CanWrite: false} && m.DeclaringType is not null && m.DeclaringType != t )
+         {
+            var newPropInfo = m.DeclaringType.GetProperty(m.Name, this.BindingFlags);
+            if( newPropInfo is not null )
+               return newPropInfo;
+         }
+
+         return m;
       }
    }
 }