Description:
------------
Using PHP 5.1.4 to connect to a postgresql 8.1.4 database, native
prepared statements.

When allocating a prepared statement and then trying to unset it, PDO
attemps to deallocate it even if it never been used (eg. when running a
query against an empty set).

PDO does not throw an exception in such case, but an error such as:
ERROR:  prepared statement "pdo_pgsql_stmt_085b2f2c" does not exist

Appers in the server log.

When running inside a transaction, such error aborts it.

Reproduce code:
---------------
$pdo->beginTransaction();

$stmt = $pdo->prepare("SELECT 'never executed'");
unset($stmt);

$res = $pdo->query('SELECT 123');

Actual result:
--------------
PHP Fatal error:  Uncaught exception 'PDOException' with message
'SQLSTATE[25P02]: In failed sql transaction: 7 ERROR:  current
transaction is aborted, commands ignored until end of transaction block'
in XXX:13
Stack trace:
#0 XXX: PDO->query('SELECT 123')

Please try using this CVS snapshot:

  http://snaps.php.net/php5.2-latest.tar.gz
 
For Windows:
 
  http://snaps.php.net/win32/php5.2-win32-latest.zip

Appears to work fine (at least for me) in latest CVS.

No feedback was provided for this bug for over a week, so it is
being suspended automatically. If you are able to provide the
information that was originally requested, please do so and change
the status of the bug back to "Open".

Same with the latest CVS version:

sagi@future:~/XXX/tmp$ /usr/local/php5-dev/bin/php -v
PHP 5.2.0RC3-dev (cli) (built: Aug 20 2006 12:46:20)
Copyright (c) 1997-2006 The PHP Group
Zend Engine v2.2.0, Copyright (c) 1998-2006 Zend Technologies
sagi@future:~/XXX/tmp$ /usr/local/php5-dev/bin/php preptest.php
PHP Fatal error:  Uncaught exception 'PDOException' with message
'SQLSTATE[25P02]: In failed sql transaction: 7 ERROR:  current
transaction is aborted, commands ignored until end of transaction block'
in /home/XXX/tmp/preptest.php:13
Stack trace:
#0 /home/XXX/tmp/preptest.php(13): PDO->query('SELECT 123')
#1 {main}
  thrown in /home/XXX/tmp/preptest.php on line 13

Fatal error: Uncaught exception 'PDOException' with message
'SQLSTATE[25P02]: In failed sql transaction: 7 ERROR:  current
transaction is aborted, commands ignored until end of transaction block'
in /home/XXX/tmp/preptest.php:13
Stack trace:
#0 /home/XXX/tmp/preptest.php(13): PDO->query('SELECT 123')
#1 {main}
  thrown in /home/XXX/tmp/preptest.php on line 13
sagi@future:~/XXX/tmp$

I would suggest the following patch:

--- pgsql_statement.c~  2006-08-30 10:54:31.000000000 +0300
+++ pgsql_statement.c   2006-08-30 10:54:31.000000000 +0300
@@ -60,10 +60,13 @@ static int pgsql_stmt_dtor(pdo_stmt_t *s
                char *q = NULL;
                PGresult *res;

-               spprintf(&q, 0, "DEALLOCATE %s", S->stmt_name);
-               res = PQexec(H->server, q);
-               efree(q);
-               if (res) PQclear(res);
+                if (S->is_prepared)
+                {
+                  spprintf(&q, 0, "DEALLOCATE %s", S->stmt_name);
+                  res = PQexec(H->server, q);
+                  efree(q);
+                  if (res) PQclear(res);
+                }
                efree(S->stmt_name);
                S->stmt_name = NULL;
        }

Transaction failing quietly for no reason is a pretty nasty bug. We have
just spent several hours troubleshooting this problem, and I can confirm
that the bug is 100% on target. If a prepared transaction is never
executed, the transaction will quietly fail.

This bug has been fixed in CVS.

Snapshots of the sources are packaged every three hours; this change
will be in the next snapshot. You can grab the snapshot at
http://snaps.php.net/.
 
Thank you for the report, and for helping us make PHP better.