Fix: OpenAPI attributes are not getting picked up if they are in a referenced class library project #298 (#301)

Author: PanosKousidis

src/Microsoft.Azure.Functions.Worker.Extensions.OpenApi/Extensions/DocumentHelperExtensions.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Reflection;

src/Microsoft.Azure.WebJobs.Extensions.OpenApi.Core/Extensions/AssemblyExtensions.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Linq;
 using System.Reflection;
 
@@ -10,15 +10,23 @@ namespace Microsoft.Azure.WebJobs.Extensions.OpenApi.Core.Extensions
     public static class AssemblyExtensions
     {
         /// <summary>
-        /// Loads the <see cref="Assembly"/>'s <see cref="Type"/>s that can be loaded ignoring others.
+        /// Loads the <see cref="Assembly"/>'s <see cref="Type"/>s that can be loaded ignoring others (includes referenced assemblies).
         /// </summary>
         /// <param name="assembly"><see cref="Assembly"/> instance.</param>
         /// <returns>Returns the list of <see cref="Type"/>s that can be loaded.</returns>
         public static Type[] GetLoadableTypes(this Assembly assembly)
         {
             try
             {
-                return assembly.GetTypes();
+                return assembly.GetTypes()
+                    .Union(assembly
+                        .GetReferencedAssemblies()
+                        .Where(x =>
+                            !x.FullName.StartsWith("Microsoft.Azure.WebJobs.Extensions.OpenApi") &&
+                            !x.FullName.StartsWith("Microsoft.Azure.Functions.Worker.Extensions.OpenApi"))
+                        .SelectMany(x => Assembly.Load(x).GetTypes()))
+                    .Distinct()
+                    .ToArray();
             }
             catch (ReflectionTypeLoadException exception)
             {

src/Microsoft.Azure.WebJobs.Extensions.OpenApi.Core/Visitors/VisitorCollection.cs

@@ -49,7 +49,7 @@ public static VisitorCollection CreateInstance()
             var collection = new VisitorCollection();
             collection.Visitors = typeof(IVisitor).Assembly
                                            .GetLoadableTypes()
-                                           .Where(p => p.Name.EndsWith("Visitor") && p.IsClass && !p.IsAbstract)
+                                           .Where(p => p.HasInterface<IVisitor>() && p.IsClass && !p.IsAbstract)
                                            .Select(p => (IVisitor)Activator.CreateInstance(p, collection)).ToList(); // NOTE: there is no direct enforcement on the constructor arguments of the visitors
             return collection;
         }