Re: [BUGS] BUG #2171: Differences compiling plpgsql in ecpg and psql

Here is an updated patch. It fixes things in the places it should be
fixed by handling \n at the time we double-quote, and double single
quotes at the place we are building the $$ string.

I am going to apply this to HEAD. It is a fix, but I am worried it
might affect ecpg users who might have worked-around these problems and
this might break their work-around. I am looking for opinions on
applying this to back releases.

---------------------------------------------------------------------------

Andrew Klosterman wrote:
> On Wed, 1 Feb 2006, Bruce Momjian wrote:
>
> >
> > I have researched your report, and you are right, there are two ecpg
> > bugs here. First, dollar quoting uses single-quotes internally to do
> > the quoting, but it does not double any single-quotes in the
> > dollar-quoted string.
> >
> > Second, when a dollar quoted string or single-quoted string spans
> > multiple lines, ecpg does not escape the newline that is part of the
> > string. Some compilers will accept an unescaped newline in a string,
> > while others will not:
> >
> > $ gcc -pedantic -c -g -Wall tst1.c
> > tst1.c:5: warning: string constant runs past end of line
> >
> > It isn't standard so I think we need to replace newline in a string with
> > "\n\".
> >
> > Attached is a patch which fixes both of these issues. This changes ecpg
> > behavior so I am thinking this patch would only appear in 8.2.
> >
> > I am unclear if I fixed the \r case properly.
> >
> > ---------------------------------------------------------------------------
> >
> > andrew5(at)ece(dot)cmu(dot)edu wrote:
> > >
> > > The following bug has been logged online:
> > >
> > > Bug reference: 2171
> > > Logged by:
> > > Email address: andrew5(at)ece(dot)cmu(dot)edu
> > > PostgreSQL version: 8.1.2
> > > Operating system: Linux (Debian)
> > > Description: Differences compiling plpgsql in ecpg and psql
> > > Details:
> > >
> > > There appear to be parsing problems with ecpg. The following example
> > > program shows code snippets that allow for the successful creation of a
> > > function (CREATE FUNCTION) only using two different syntaxes: one when
> > > entered through psql, and another when compiling with ecpg.
> > >
> > > The expectation (and hints from the documentation) indicate that the exact
> > > same method of defining a function should succeed in both cases, but such is
> > > not the case.
> > >
> > > Different quoting and line-wrap behavior is observed between psql and ecpg.
> > >
> > > (Thanks for the attention, I hope this is useful!)
> > >
> > > BEGIN CODE---------------
> > > /* This file is bug.pgc. */
> > > /* Compile as shown:
> > > ecpg bug.pgc -o bug.c
> > > gcc -c -g -std=c99 -I/usr/local/pgsql/include -L/usr/local/pgsql/lib
> > > bug.c -o bug.o
> > > gcc -I/usr/local/pgsql/include -L/usr/local/pgsql/lib -lecpg bug.o -o bug
> > > */
> > > /* Run as: ./bug */
> > > #include <stdio.h>
> > > #include <stdlib.h>
> > > #include <string.h>
> > >
> > > int main(int argc, char* argv[]) {
> > >
> > > EXEC SQL CONNECT TO DEFAULT;
> > >
> > > EXEC SQL SET AUTOCOMMIT TO ON;
> > > EXEC SQL WHENEVER SQLWARNING SQLPRINT;
> > > EXEC SQL WHENEVER SQLERROR SQLPRINT;
> > >
> > > EXEC SQL CREATE TABLE My_Table ( Item1 int, Item2 text );
> > >
> > > /* Documentation appears to indicate that only single quotes (') are
> > > needed, but this will not ecpg-compile without double-single ('')
> > > quotes. When entered through psql, only the single quotes (')
> > > are needed. */
> > > /* doc/html/sql-syntax.html#SQL-SYNTAX-DOLLAR-QUOTING: "It is
> > > particularly useful when representing string constants inside
> > > other constants, as is often needed in procedural function
> > > definitions." */
> > > /* doc/html/sql-createfunction.html: "Without dollar quoting, any
> > > single quotes or backslashes in the function definition must be
> > > escaped by doubling them." */
> > >
> > > /* Documentation appears to indicate that the body of the funtion
> > > can be extended across multiple lines in the input file (this
> > > file) but it will not compile (ecpg) without keeping the function
> > > body on one line. Multiple line input works through psql, but
> > > not here.*/
> > > //bad ecpg,good psql: EXEC SQL CREATE FUNCTION My_Table_Check() RETURNS
> > > trigger
> > > //bad ecpg,good psql: AS $My_Table_Check$
> > > //bad ecpg,good psql: BEGIN RAISE NOTICE 'TG_NAME=%, TG WHEN=%', TG_NAME,
> > > TG_WHEN;
> > > //bad ecpg,good psql: RETURN NEW;
> > > //bad ecpg,good psql: END;
> > > //bad ecpg,good psql: $My_Table_Check$
> > > //bad ecpg,good psql: LANGUAGE 'plpgsql';
> > > EXEC SQL CREATE FUNCTION My_Table_Check() RETURNS trigger
> > > AS $My_Table_Check$ BEGIN RAISE NOTICE ''TG_NAME=%, TG WHEN=%'',
> > > TG_NAME, TG_WHEN; RETURN NEW; END; $My_Table_Check$
> > > LANGUAGE 'plpgsql';
> > >
> > > EXEC SQL CREATE TRIGGER My_Table_Check_Trigger
> > > BEFORE INSERT
> > > ON My_Table
> > > FOR EACH ROW
> > > EXECUTE PROCEDURE My_Table_Check();
> > >
> > > EXEC SQL INSERT INTO My_Table VALUES (1234, 'Some random text');
> > > EXEC SQL INSERT INTO My_Table VALUES (5678, 'The Quick Brown');
> > >
> > > EXEC SQL DROP TRIGGER My_Table_Check_Trigger ON My_Table;
> > > EXEC SQL DROP FUNCTION My_Table_Check();
> > > EXEC SQL DROP TABLE My_Table;
> > >
> > > EXEC SQL DISCONNECT ALL;
> > >
> > > return 0;
> > > }
> > >
> > > END CODE------------------
> > >
> > > ---------------------------(end of broadcast)---------------------------
> > > TIP 9: In versions below 8.0, the planner will ignore your desire to
> > > choose an index scan if your joining column's datatypes do not
> > > match
> > >
> >
> > --
> > Bruce Momjian | http://candle.pha.pa.us
> > pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 359-1001
> > + If your life is a hard drive, | 13 Roberts Road
> > + Christ can be your backup. | Newtown Square, Pennsylvania 19073
> >
>
>
> --Andrew J. Klosterman
> andrew5(at)ece(dot)cmu(dot)edu
>

--
Bruce Momjian | http://candle.pha.pa.us
pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 359-1001
+ If your life is a hard drive, | 13 Roberts Road
+ Christ can be your backup. | Newtown Square, Pennsylvania 19073