Merge pull request #25849 from suginoy/fix_merge_in_scope

Fix the calling `merge` method at first in a scope

activerecord/CHANGELOG.md

+*   Support calling the method `merge` in `scope`'s lambda.
+
+    *Yasuhiro Sugino*
+
 *   Fixes multi-parameter attributes conversion with invalid params.
 
     *Hiroyuki Ishii*

activerecord/lib/active_record/querying.rb

@@ -9,7 +9,7 @@ module Querying
     delegate :find_each, :find_in_batches, :in_batches, to: :all
     delegate :select, :group, :order, :except, :reorder, :limit, :offset, :joins, :left_joins, :left_outer_joins, :or,
              :where, :rewhere, :preload, :eager_load, :includes, :from, :lock, :readonly,
-             :having, :create_with, :uniq, :distinct, :references, :none, :unscope, to: :all
+             :having, :create_with, :uniq, :distinct, :references, :none, :unscope, :merge, to: :all
     delegate :count, :average, :minimum, :maximum, :sum, :calculate, to: :all
     delegate :pluck, :ids, to: :all
 

activerecord/test/cases/scoping/named_scoping_test.rb

@@ -46,6 +46,13 @@ def test_delegates_finds_and_calculations_to_the_base_class
     assert_equal Topic.average(:replies_count), Topic.base.average(:replies_count)
   end
 
+  def test_calling_merge_at_first_in_scope
+    Topic.class_eval do
+      scope :calling_merge_at_first_in_scope, Proc.new { merge(Topic.replied) }
+    end
+    assert_equal Topic.calling_merge_at_first_in_scope.to_a, Topic.replied.to_a
+  end
+
   def test_method_missing_priority_when_delegating
     klazz = Class.new(ActiveRecord::Base) do
       self.table_name = "topics"