ORA-01403: no data found on ctxposup.sql while upgrading from 11g to 12.2

From: Oracle Database - Enterprise Edition - Version 11.2.0.3 + PSU 11.2.0.3.5 (14727310)
To:   Oracle Database - Enterprise Edition - Version 12.2.0.1.0
Operation System -  Solaris 10 1/13 s10s_u11wos_24a SPARC

It failed to upgrade database from 11.2.3 to 12.2 with error 'ORA-01403: no data found', and following message is found from log file 'Oracle_Server.log',

REASON:
      ERRORS FOUND: During Upgrade
         FILENAME: /u01/app/oracle/cfgtoollogs/dbua/upgrade2018-01-17_11-42-08-AM/DB01/catupgrd0.log AT LINE NUMBER: 825076
------------------------------------------------------
Identifier CONTEXT 18-01-17 12:37:20
SCRIPT      = [/u01/app/oracle/product/12.2.0/dbhome_1/ctx/admin/ctxposup.sql] <===== STATEMENT 1
ERROR      = [ORA-01403: no data found ORA-06512: at line 28
ORA-06512: at line 8
]
STATEMENT = [declare
  l_owner#  number;
  l_errnum  number;
  l_count   number;

begin
  select user# into l_owner# from sys."_BASE_USER" where name='CTXSYS';
  select idx_id into l_count from dr$index where        <===== STATEMENT 2
    idx_name = 'ENT_EXT_DICT_OBJ' and          
    idx_owner# = l_owner#;                       

  /* if this object does not exist yet, create it. */  
  if (0 = l_count) then
    CTX_DDL.create_policy('CTXSYS.ENT_EXT_DICT_OBJ',    <===== STATEMENT 3
      filter        => 'CTXSYS.NULL_FILTER',
      section_group => 'CTXSYS.NULL_SECTION_GROUP',
      lexer        => 'CTXSYS.BASIC_LEXER',
      stoplist        => 'CTXSYS.EMPTY_STOPLIST',
      wordlist        => 'CTXSYS.BASIC_WORDLIST'
  );
  end if;
exception
  when others then
    l_errnum := SQLCODE;
    if (l_errnum = -20000) then
      null;
    else
      raise;
    end if;
end;]

Script ctxposup.sql (STATEMENT 1) which upgrades Oracle Text raised ORA-01403 while running PL/SQL block listed in the above. Testing individual statements in the block as following:

sys@DB01> select user#  from sys."_BASE_USER" where name='CTXSYS';

     USER#
----------
       100

sys@DB01> ALTER SESSION SET CURRENT_SCHEMA = CTXSYS;

Session altered.

sys@DB01> select idx_id from dr$index where
  2    idx_name = 'ENT_EXT_DICT_OBJ' and
  3    idx_owner# = 100;

no rows selected

The object CTXSYS.ENT_EXT_DICT_OBJ (a policy of Oracle Text) does not exist in the database. Therefore, STATEMENT 2 (select ... into ... from) returned ORA-01403. Apparently, The purpose of STATEMENT 2 is to test whether CTXSYS.ENT_EXT_DICT_OBJ exists, but listing records is not a better choice for exist-testing than counting the number of records. Let's try to replace STATEMENT 2 in script filectxposup.sql with following code

 select count(idx_id) into l_count from dr$index where

Start the upgrade again, it succeeded!