Merge pull request #1926 from Bond-009/auth

Add clearer exceptions, warnings and docs

MediaBrowser.Controller/Entities/Folder.cs

@@ -1152,6 +1152,11 @@ namespace MediaBrowser.Controller.Entities
 
         public List<BaseItem> GetChildren(User user, bool includeLinkedChildren)
         {
+            if (user == null)
+            {
+                throw new ArgumentNullException(nameof(user));
+            }
+
             return GetChildren(user, includeLinkedChildren, null);
         }
 
@@ -1163,7 +1168,10 @@ namespace MediaBrowser.Controller.Entities
             }
 
             //the true root should return our users root folder children
-            if (IsPhysicalRoot) return LibraryManager.GetUserRootFolder().GetChildren(user, includeLinkedChildren);
+            if (IsPhysicalRoot)
+            {
+                return LibraryManager.GetUserRootFolder().GetChildren(user, includeLinkedChildren);
+            }
 
             var result = new Dictionary<Guid, BaseItem>();
 

MediaBrowser.Controller/Library/IUserManager.cs

@@ -39,17 +39,21 @@ namespace MediaBrowser.Controller.Library
         event EventHandler<GenericEventArgs<User>> UserDeleted;
 
         event EventHandler<GenericEventArgs<User>> UserCreated;
+
         event EventHandler<GenericEventArgs<User>> UserPolicyUpdated;
+
         event EventHandler<GenericEventArgs<User>> UserConfigurationUpdated;
+
         event EventHandler<GenericEventArgs<User>> UserPasswordChanged;
+
         event EventHandler<GenericEventArgs<User>> UserLockedOut;
 
         /// <summary>
-        /// Gets a User by Id
+        /// Gets a User by Id.
         /// </summary>
         /// <param name="id">The id.</param>
-        /// <returns>User.</returns>
-        /// <exception cref="ArgumentNullException"></exception>
+        /// <returns>The user with the specified Id, or <c>null</c> if the user doesn't exist.</returns>
+        /// <exception cref="ArgumentException"><c>id</c> is an empty Guid.</exception>
         User GetUserById(Guid id);
 
         /// <summary>