Use of backslash in tsearch2 - Mailing list pgsql-patches

Bruce Momjian wrote:
>
> I backed out the patch, attached, and it has fixed the regression
> problem.  What has me confused is that is looks like it is checking for
> ', then putting \, which doesn't make a lot of sense, but the regression
> output is corrected, so I just don't get it.  Here is an example:
>
>     test=> SELECT E'''1 \\''2''';
>      ?column?
>     ----------
>      '1 \'2'
>
> My only guess is that the output is somehow a single-quoted string
> itself, and in fact \' should become ''.  Is that right?  Basically they
> are doing \' in their output, and it should be doing '', but then the
> query above would be wrong and shouldn't be using \'.

As part of the move to support standard-conforming strings and treat
backslash literally, I reviewed the tsearch2 code and found two place
that seemed to use \' rather than '', and generated the attached patch.
('' is standards conforming.)  However, when I fixed the code, the
regression tests failed.

Teodor, are the new attached regression results correct?  If so, I will
apply the patch and update the expected file.

--
  Bruce Momjian   bruce@momjian.us
  EnterpriseDB    http://www.enterprisedb.com

  + If your life is a hard drive, Christ can be your backup. +
Index: contrib/tsearch2/query.c
===================================================================
RCS file: /cvsroot/pgsql/contrib/tsearch2/query.c,v
retrieving revision 1.25
diff -c -c -r1.25 query.c
*** contrib/tsearch2/query.c    19 May 2006 02:38:47 -0000    1.25
--- contrib/tsearch2/query.c    19 May 2006 04:37:35 -0000
***************
*** 748,754 ****
          {
              if ( t_iseq(op, '\'') )
              {
!                 *(in->cur) = '\'';
                  in->cur++;
              }
              COPYCHAR(in->cur,op);
--- 748,754 ----
          {
              if ( t_iseq(op, '\'') )
              {
!                 *(in->cur) = '\\';
                  in->cur++;
              }
              COPYCHAR(in->cur,op);
Index: contrib/tsearch2/tsvector.c
===================================================================
RCS file: /cvsroot/pgsql/contrib/tsearch2/tsvector.c,v
retrieving revision 1.18
diff -c -c -r1.18 tsvector.c
*** contrib/tsearch2/tsvector.c    19 May 2006 02:38:47 -0000    1.18
--- contrib/tsearch2/tsvector.c    19 May 2006 04:37:39 -0000
***************
*** 529,535 ****

                  outbuf = (char *) repalloc((void *) outbuf, ++lenbuf);
                  curout = outbuf + pos;
!                 *curout++ = '\'';
              }
              while(len--)
                  *curout++ = *curin++;
--- 529,535 ----

                  outbuf = (char *) repalloc((void *) outbuf, ++lenbuf);
                  curout = outbuf + pos;
!                 *curout++ = '\\';
              }
              while(len--)
                  *curout++ = *curin++;
*** ./expected/tsearch2.out    Wed May 31 10:05:31 2006
--- ./results/tsearch2.out    Mon Aug 21 20:01:12 2006
***************
*** 59,83 ****
  SELECT E'''1 \\''2'''::tsvector;
   tsvector
  ----------
!  '1 \'2'
  (1 row)

  SELECT E'''1 \\''2''3'::tsvector;
    tsvector
  -------------
!  '3' '1 \'2'
  (1 row)

  SELECT E'''1 \\''2'' 3'::tsvector;
    tsvector
  -------------
!  '3' '1 \'2'
  (1 row)

  SELECT E'''1 \\''2'' '' 3'' 4 '::tsvector;
       tsvector
  ------------------
!  '4' ' 3' '1 \'2'
  (1 row)

  select '''w'':4A,3B,2C,1D,5 a:8';
--- 59,83 ----
  SELECT E'''1 \\''2'''::tsvector;
   tsvector
  ----------
!  '1 ''2'
  (1 row)

  SELECT E'''1 \\''2''3'::tsvector;
    tsvector
  -------------
!  '3' '1 ''2'
  (1 row)

  SELECT E'''1 \\''2'' 3'::tsvector;
    tsvector
  -------------
!  '3' '1 ''2'
  (1 row)

  SELECT E'''1 \\''2'' '' 3'' 4 '::tsvector;
       tsvector
  ------------------
!  '4' ' 3' '1 ''2'
  (1 row)

  select '''w'':4A,3B,2C,1D,5 a:8';
***************
*** 138,144 ****
  SELECT E'''1 \\''2'''::tsquery;
   tsquery
  ---------
!  '1 \'2'
  (1 row)

  SELECT '!1'::tsquery;
--- 138,144 ----
  SELECT E'''1 \\''2'''::tsquery;
   tsquery
  ---------
!  '1 ''2'
  (1 row)

  SELECT '!1'::tsquery;
***************
*** 336,342 ****
  SELECT E'1&(''2''&('' 4''&(\\|5 | ''6 \\'' !|&'')))'::tsquery;
                   tsquery
  ------------------------------------------
!  '1' & '2' & ' 4' & ( '|5' | '6 \' !|&' )
  (1 row)

  SELECT '''the wether'':dc & '' sKies '':BC & a:d b:a';
--- 336,342 ----
  SELECT E'1&(''2''&('' 4''&(\\|5 | ''6 \\'' !|&'')))'::tsquery;
                   tsquery
  ------------------------------------------
!  '1' & '2' & ' 4' & ( '|5' | '6 '' !|&' )
  (1 row)

  SELECT '''the wether'':dc & '' sKies '':BC & a:d b:a';

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