From e4d5b2f3bece0f5f3e5f588e20e52031ad33e124 Mon Sep 17 00:00:00 2001
From: "M.Shibuya" <mit.shibuya@gmail.com>
Date: Fri, 22 Oct 2021 17:44:01 +0900
Subject: [PATCH] Fix N+1 queries for ActiveStorage attachments

Closes #3282
---
 lib/rails_admin/config/fields/types/active_storage.rb       | 4 ++++
 .../config/fields/types/multiple_active_storage.rb          | 4 ++++
 spec/rails_admin/config/fields/types/active_storage_spec.rb | 6 ++++++
 .../config/fields/types/multiple_active_storage_spec.rb     | 6 ++++++
 4 files changed, 20 insertions(+)

diff --git a/lib/rails_admin/config/fields/types/active_storage.rb b/lib/rails_admin/config/fields/types/active_storage.rb
index d0ce0966c2..affb6da485 100644
--- a/lib/rails_admin/config/fields/types/active_storage.rb
+++ b/lib/rails_admin/config/fields/types/active_storage.rb
@@ -22,6 +22,10 @@ class ActiveStorage < RailsAdmin::Config::Fields::Types::FileUpload
             end
           end
 
+          register_instance_option :eager_load do
+            {"#{name}_attachment": :blob}
+          end
+
           def resource_url(thumb = false)
             return nil unless value
             if thumb && value.variable?
diff --git a/lib/rails_admin/config/fields/types/multiple_active_storage.rb b/lib/rails_admin/config/fields/types/multiple_active_storage.rb
index d049d2868f..7157adf8b9 100644
--- a/lib/rails_admin/config/fields/types/multiple_active_storage.rb
+++ b/lib/rails_admin/config/fields/types/multiple_active_storage.rb
@@ -43,6 +43,10 @@ def resource_url(thumb = false)
           register_instance_option :delete_method do
             "remove_#{name}" if bindings[:object].respond_to?("remove_#{name}")
           end
+
+          register_instance_option :eager_load do
+            {"#{name}_attachments": :blob}
+          end
         end
       end
     end
diff --git a/spec/rails_admin/config/fields/types/active_storage_spec.rb b/spec/rails_admin/config/fields/types/active_storage_spec.rb
index 47ff5feff9..c582290945 100644
--- a/spec/rails_admin/config/fields/types/active_storage_spec.rb
+++ b/spec/rails_admin/config/fields/types/active_storage_spec.rb
@@ -84,4 +84,10 @@
       end
     end
   end
+
+  describe '#eager_load' do
+    it 'points to associations to be eager-loaded' do
+      expect(field.eager_load).to eq({active_storage_asset_attachment: :blob})
+    end
+  end
 end if defined?(ActiveStorage)
diff --git a/spec/rails_admin/config/fields/types/multiple_active_storage_spec.rb b/spec/rails_admin/config/fields/types/multiple_active_storage_spec.rb
index 6afb772319..c5c1e4d098 100644
--- a/spec/rails_admin/config/fields/types/multiple_active_storage_spec.rb
+++ b/spec/rails_admin/config/fields/types/multiple_active_storage_spec.rb
@@ -88,4 +88,10 @@
       end
     end
   end
+
+  describe '#eager_load' do
+    it 'points to associations to be eager-loaded' do
+      expect(field.eager_load).to eq({active_storage_assets_attachments: :blob})
+    end
+  end
 end if defined?(ActiveStorage)