Consolidate account scopes for LOWER (index using) username/domain queries (#30451)

app/models/concerns/account/finder_concern.rb

@@ -25,42 +25,11 @@ module Account::FinderConcern
     end
 
     def find_remote(username, domain)
-      AccountFinder.new(username, domain).account
-    end
-  end
-
-  class AccountFinder
-    attr_reader :username, :domain
-
-    def initialize(username, domain)
-      @username = username
-      @domain = domain
-    end
-
-    def account
-      scoped_accounts.order(id: :asc).take
-    end
-
-    private
-
-    def scoped_accounts
-      Account.unscoped.tap do |scope|
-        scope.merge! with_usernames
-        scope.merge! matching_username
-        scope.merge! matching_domain
-      end
-    end
-
-    def with_usernames
-      Account.where.not(Account.arel_table[:username].lower.eq '')
-    end
-
-    def matching_username
-      Account.where(Account.arel_table[:username].lower.eq username.to_s.downcase)
-    end
-
-    def matching_domain
-      Account.where(Account.arel_table[:domain].lower.eq(domain.nil? ? nil : domain.to_s.downcase))
+      Account
+        .with_username(username)
+        .with_domain(domain)
+        .order(id: :asc)
+        .take
     end
   end
 end

app/models/concerns/user/ldap_authenticable.rb

@@ -22,7 +22,7 @@ module User::LdapAuthenticable
         safe_username = safe_username.gsub(keys, replacement)
       end
 
-      resource = joins(:account).merge(Account.where(Account.arel_table[:username].lower.eq safe_username.downcase)).take
+      resource = joins(:account).merge(Account.with_username(safe_username)).take
 
       if resource.blank?
         resource = new(