Enumerate columns to address db query cache issues on column change

app/finders/members_finder.rb

@@ -83,7 +83,10 @@ class MembersFinder
     union = Gitlab::SQL::Union.new(union_members, remove_duplicates: false) # rubocop: disable Gitlab/Union
     sql = distinct_on(union)
 
-    Member.includes(:user).from([Arel.sql("(#{sql}) AS #{Member.table_name}")]) # rubocop: disable CodeReuse/ActiveRecord
+    # enumerate the columns here since we are enumerating them in the union and want to be immune to
+    # column caching issues when adding/removing columns
+    Member.select(*Member.column_names)
+          .includes(:user).from([Arel.sql("(#{sql}) AS #{Member.table_name}")]) # rubocop: disable CodeReuse/ActiveRecord
   end
 
   def distinct_on(union)

app/models/members/group_member.rb

@@ -28,6 +28,8 @@ class GroupMember < Member
 
   attr_accessor :last_owner, :last_blocked_owner
 
+  self.enumerate_columns_in_select_statements = true
+
   def self.access_level_roles
     Gitlab::Access.options_with_owner
   end

app/services/jira_import/users_mapper_service.rb

@@ -77,7 +77,7 @@ module JiraImport
     end
 
     def project_member_ids
-      @project_member_ids ||= MembersFinder.new(project, current_user).execute.select(:user_id)
+      @project_member_ids ||= MembersFinder.new(project, current_user).execute.reselect(:user_id)
     end
   end
 end

config/initializers/active_record_build_select.rb

@@ -9,6 +9,10 @@
 # statement cache. If a different migration is then run and one of these columns is
 # removed in the meantime, the query is invalid.
 
+ActiveRecord::Base.class_eval do
+  class_attribute :enumerate_columns_in_select_statements
+end
+
 module ActiveRecord
   module QueryMethods
     private
@@ -16,6 +20,8 @@ module ActiveRecord
     def build_select(arel)
       if select_values.any?
         arel.project(*arel_columns(select_values.uniq))
+      elsif klass.enumerate_columns_in_select_statements
+        arel.project(*klass.column_names.map { |field| table[field] })
       else
         arel.project(@klass.arel_table[Arel.star])
       end

ee/app/services/ee/boards/lists/create_service.rb

@@ -89,8 +89,8 @@ module EE
 
         # rubocop: disable CodeReuse/ActiveRecord
         def find_user(board)
-          user_ids = user_finder(board).execute.select(:user_id)
-          ::User.where(id: user_ids).find_by(id: params['assignee_id'])
+          user_ids = user_finder(board).execute.reselect(:user_id)
+          ::User.id_in(user_ids).find_by(id: params['assignee_id'])
         end
         # rubocop: enable CodeReuse/ActiveRecord
 

ee/lib/ee/gitlab/background_migration/remove_inaccessible_epic_todos.rb

@@ -19,6 +19,7 @@ module EE
           include FromUnion
 
           self.inheritance_column = :_type_disabled
+          self.enumerate_columns_in_select_statements = true
         end
 
         class GroupGroupLink < ActiveRecord::Base