Merge pull request #36930 from eugeneius/active_record_base_connection_specification_name

Fix setting connection_specification_name on ActiveRecord::Base

activerecord/lib/active_record/connection_handling.rb

@@ -204,7 +204,7 @@ def connection
     # Return the specification name from the current class or its parent.
     def connection_specification_name
       if !defined?(@connection_specification_name) || @connection_specification_name.nil?
-        return primary_class? ? "primary" : superclass.connection_specification_name
+        return self == Base ? "primary" : superclass.connection_specification_name
       end
       @connection_specification_name
     end

activerecord/test/cases/connection_adapters/connection_handler_test.rb

@@ -375,6 +375,8 @@ class MyClass < ApplicationRecord
         end
 
         def test_connection_specification_name_should_fallback_to_parent
+          Object.send :const_set, :ApplicationRecord, ApplicationRecord
+
           klassA = Class.new(Base)
           klassB = Class.new(klassA)
           klassC = Class.new(MyClass)
@@ -387,6 +389,12 @@ def test_connection_specification_name_should_fallback_to_parent
 
           klassA.connection_specification_name = "readonly"
           assert_equal "readonly", klassB.connection_specification_name
+
+          ActiveRecord::Base.connection_specification_name = "readonly"
+          assert_equal "readonly", klassC.connection_specification_name
+        ensure
+          Object.send :remove_const, :ApplicationRecord
+          ActiveRecord::Base.connection_specification_name = "primary"
         end
 
         def test_remove_connection_should_not_remove_parent