Fix #1315: Use base type for open generic arg matching.

autofac · Mar 18, 2022 · 219ba41 · 219ba41
1 parent 82dedce
commit 219ba41
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Showing 2 changed files with 51 additions and 1 deletion.
diff --git a/src/Autofac/Features/OpenGenerics/OpenGenericServiceBinder.cs b/src/Autofac/Features/OpenGenerics/OpenGenericServiceBinder.cs
@@ -173,7 +173,18 @@ public static bool TryBindOpenGenericDelegateService(
 
         if (!serviceType.IsInterface)
         {
-            return TryFindServiceArgumentsForImplementation(implementationType, serviceGenericArguments, serviceTypeDefinition.GetGenericArguments());
+            var baseType = GetGenericBaseType(implementationType, serviceTypeDefinition);
+            if (baseType == null)
+            {
+                // If it's not an interface, the implementation type MUST have derived from
+                // the generic service type at some point or there's no way to cast.
+                return Array.Empty<Type>();
+            }
+
+            return TryFindServiceArgumentsForImplementation(
+                    implementationType,
+                    serviceGenericArguments,
+                    baseType.GenericTypeArguments);
         }
 
         var availableArguments = GetInterfaces(implementationType, serviceType)
@@ -199,6 +210,22 @@ public static bool TryBindOpenGenericDelegateService(
             .ToArray();
     }
 
+    private static Type? GetGenericBaseType(Type implementationType, Type serviceTypeDefinition)
+    {
+        var baseType = implementationType.BaseType;
+        while (baseType != null)
+        {
+            if (baseType.IsGenericType && baseType.GetGenericTypeDefinition() == serviceTypeDefinition)
+            {
+                break;
+            }
+
+            baseType = baseType.BaseType;
+        }
+
+        return baseType;
+    }
+
     private static Type[] GetInterfaces(Type implementationType, Type serviceType) =>
         implementationType.GetInterfaces()
             .Where(i => i.Name == serviceType.Name && i.Namespace == serviceType.Namespace)

diff --git a/test/Autofac.Specification.Test/Registration/OpenGenericTests.cs b/test/Autofac.Specification.Test/Registration/OpenGenericTests.cs
@@ -42,7 +42,30 @@ public void ResolveWithMultipleCandidatesLimitedByGenericConstraintsShouldSuccee
         Assert.NotNull(resolved);
     }
 
+    // Issue #1315: Class services fail to resolve if the names on the type
+    // arguments are changed.
+    [Fact]
+    public void ResolveClassWithRenamedTypeArguments()
+    {
+        var containerBuilder = new ContainerBuilder();
+        containerBuilder.RegisterGeneric(typeof(DerivedRepository<,>)).As(typeof(BaseRepository<,>));
+
+        var container = containerBuilder.Build();
+        var resolved = container.Resolve<BaseRepository<string, int>>();
+        Assert.IsType<DerivedRepository<int, string>>(resolved);
+    }
+
     private class SelfComponent<T> : IImplementedInterface<T>
     {
     }
+
+    private class BaseRepository<T1, T2>
+    {
+    }
+
+    // Issue #1315: Class services fail to resolve if the names on the type
+    // arguments are changed.
+    private class DerivedRepository<TSecond, TFirst> : BaseRepository<TFirst, TSecond>
+    {
+    }
 }