Merge pull request #1369 from autofac/feature/ignore-required-props-i…

…n-prop-autowiring

Ignore required properties in the default autowiring property selector.

src/Autofac/Core/Activators/DefaultPropertySelector.cs

@@ -2,6 +2,7 @@
 // Licensed under the MIT License. See LICENSE in the project root for license information.
 
 using System.Reflection;
+using System.Runtime.CompilerServices;
 
 namespace Autofac.Core;
 
@@ -55,6 +56,18 @@ public virtual bool InjectProperty(PropertyInfo propertyInfo, object instance)
             return false;
         }
 
+#if NET7_0_OR_GREATER
+        if (propertyInfo.GetCustomAttribute<RequiredMemberAttribute>() is not null)
+        {
+            // The default property selector should not inject required properties,
+            // to avoid duplication with the injection automatically applied inside the
+            // ReflectionActivator.
+            // Any other form of activator (lambda, instance) would generally already be required to
+            // set the required properties in order to create the instance.
+            return false;
+        }
+#endif
+
         if (PreserveSetValues && propertyInfo.CanRead)
         {
             try

test/Autofac.Test/Core/DefaultPropertySelectorTests.cs

@@ -18,12 +18,20 @@ public class DefaultPropertySelectorTests
     [InlineData(true, "PublicPropertyNoSet", false)]
     [InlineData(true, "PublicPropertyThrowsOnGet", false)]
     [InlineData(false, "PublicPropertyThrowsOnGet", true)]
+#if NET7_0_OR_GREATER
+    [InlineData(false, "PublicRequiredProperty", false)]
+#endif
     [Theory]
     public void DefaultTests(bool preserveSetValue, string propertyName, bool expected)
     {
         var finder = new DefaultPropertySelector(preserveSetValue);
 
-        var instance = new HasProperties();
+        var instance = new HasProperties
+        {
+#if NET7_0_OR_GREATER
+            PublicRequiredProperty = new(),
+#endif
+        };
         var property = instance.GetType().GetProperty(propertyName, BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance);
 
         Assert.Equal(expected, finder.InjectProperty(property, instance));
@@ -53,6 +61,10 @@ public Test PublicPropertyThrowsOnGet
             }
         }
 
+#if NET7_0_OR_GREATER
+        required public Test PublicRequiredProperty { get; set; }
+#endif
+
         public Test PublicPropertyWithDefault { get; set; } = new Test();
 
         private Test PrivatePropertyWithDefault { get; set; } = new Test();