Fix frozen string errors

Author: DavidS

lib/puppet/provider/mysql.rb

@@ -145,7 +145,7 @@ def self.cmd_table(table)
     table_string = ''
 
     # We can't escape *.* so special case this.
-    table_string << if table == '*.*'
+    table_string += if table == '*.*'
                       '*.*'
                     # Special case also for FUNCTIONs and PROCEDUREs
                     elsif table.start_with?('FUNCTION ', 'PROCEDURE ')
@@ -160,7 +160,7 @@ def self.cmd_privs(privileges)
     return 'ALL PRIVILEGES' if privileges.include?('ALL')
     priv_string = ''
     privileges.each do |priv|
-      priv_string << "#{priv}, "
+      priv_string += "#{priv}, "
     end
     # Remove trailing , from the last element.
     priv_string.sub(%r{, $}, '')
@@ -170,7 +170,7 @@ def self.cmd_privs(privileges)
   def self.cmd_options(options)
     option_string = ''
     options.each do |opt|
-      option_string << ' WITH GRANT OPTION' if opt == 'GRANT'
+      option_string += ' WITH GRANT OPTION' if opt == 'GRANT'
     end
     option_string
   end

lib/puppet/provider/mysql_user/mysql.rb

@@ -159,8 +159,8 @@ def password_hash=(string)
       else
         concat_name = @resource[:name]
         sql = "UPDATE mysql.user SET password = '', plugin = 'ed25519'"
-        sql << ", authentication_string = '#{string}'"
-        sql << " where CONCAT(user, '@', host) = '#{concat_name}'; FLUSH PRIVILEGES"
+        sql += ", authentication_string = '#{string}'"
+        sql += " where CONCAT(user, '@', host) = '#{concat_name}'; FLUSH PRIVILEGES"
       end
       self.class.mysql_caller(sql, 'system')
     elsif newer_than('mysql' => '5.7.6', 'percona' => '5.7.6', 'mariadb' => '10.2.0')
@@ -210,17 +210,17 @@ def plugin=(string)
       else
         concat_name = @resource[:name]
         sql = "UPDATE mysql.user SET password = '', plugin = '#{string}'"
-        sql << ", authentication_string = '#{@resource[:password_hash]}'"
-        sql << " where CONCAT(user, '@', host) = '#{concat_name}'; FLUSH PRIVILEGES"
+        sql += ", authentication_string = '#{@resource[:password_hash]}'"
+        sql += " where CONCAT(user, '@', host) = '#{concat_name}'; FLUSH PRIVILEGES"
       end
     elsif newer_than('mysql' => '5.7.6', 'percona' => '5.7.6', 'mariadb' => '10.2.0')
       sql = "ALTER USER #{merged_name} IDENTIFIED WITH '#{string}'"
-      sql << " AS '#{@resource[:password_hash]}'" if string == 'mysql_native_password'
+      sql += " AS '#{@resource[:password_hash]}'" if string == 'mysql_native_password'
     else
       # See https://bugs.mysql.com/bug.php?id=67449
       sql = "UPDATE mysql.user SET plugin = '#{string}'"
-      sql << ((string == 'mysql_native_password') ? ", password = '#{@resource[:password_hash]}'" : ", password = ''")
-      sql << " WHERE CONCAT(user, '@', host) = '#{@resource[:name]}'"
+      sql += ((string == 'mysql_native_password') ? ", password = '#{@resource[:password_hash]}'" : ", password = ''")
+      sql += " WHERE CONCAT(user, '@', host) = '#{@resource[:name]}'"
     end
 
     self.class.mysql_caller(sql, 'system')