Handle STI models where the resource is generated for the superclass

app/views/madmin/fields/belongs_to/_index.html.erb

@@ -1,3 +1,4 @@
 <% if (object = field.value(record)) %>
-  <%= link_to Madmin.resource_for(object).display_name(object), Madmin.resource_for(object).show_path(object) %>
+  <% object_resource = Madmin.resource_for(object) %>
+  <%= link_to object_resource.display_name(object), object_resource.show_path(object) %>
 <% end %>

lib/madmin.rb

@@ -39,7 +39,16 @@ def resource_for(object)
       if object.is_a? ::ActiveStorage::Attached
         "ActiveStorage::AttachmentResource".constantize
       else
-        "#{object.class.name}Resource".constantize
+        begin
+          "#{object.class.name}Resource".constantize
+        rescue
+          # For STI models, see if there's a superclass resource available
+          if object.class.inheritance_column.present?
+            "#{object.class.superclass.name}Resource".constantize
+          else
+            raise
+          end
+        end
       end
     end
 

lib/madmin/resource.rb

@@ -14,12 +14,17 @@ def inherited(base)
         super
       end
 
-      def model
-        @model ||= model_name.constantize
+      def model(value=nil)
+        if value
+          @model = value
+        else
+          @model ||= model_name.constantize
+        end
       end
 
       def model_find(id)
-        friendly_model? ? model.friendly.find(id) : model.find(id)
+        record = friendly_model? ? model.friendly.find(id) : model.find(id)
+        becomes(record)
       end
 
       def model_name
@@ -95,11 +100,15 @@ def new_path
       end
 
       def show_path(record)
-        url_helpers.polymorphic_path([:madmin, route_namespace, record])
+        url_helpers.polymorphic_path([:madmin, route_namespace, becomes(record)])
       end
 
       def edit_path(record)
-        url_helpers.polymorphic_path([:madmin, route_namespace, record], action: :edit)
+        url_helpers.polymorphic_path([:madmin, route_namespace, becomes(record)], action: :edit)
+      end
+
+      def becomes(record)
+        record.class == model ? record : record.becomes(model)
       end
 
       def param_key