From c08c8529e707ded90f5b3366a9c17fa7d435e978 Mon Sep 17 00:00:00 2001
From: Neil Conway <neilc@samurai.com>
Date: Tue, 10 Jan 2006 00:33:12 +0000
Subject: [PATCH] In PLy_function_build_args(), the code loops repeatedly,
 constructing one argument at a time and then inserting the argument into a
 Python list via PyList_SetItem(). This "steals" the reference to the
 argument: that is, the reference to the new list member is now held by the
 Python list itself. This works fine, except if an elog occurs. This causes
 the function's PG_CATCH() block to be invoked, which decrements the reference
 counts on both the current argument and the list of arguments. If the elog
 happens to occur during the second or subsequent iteration of the loop, the
 reference count on the current argument will be decremented twice.

The fix is simple: set the local pointer to the current argument to NULL
immediately after adding it to the argument list. This ensures that the
Py_XDECREF() in the PG_CATCH() block doesn't double-decrement.
---
 src/pl/plpython/plpython.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/pl/plpython/plpython.c b/src/pl/plpython/plpython.c
index 39acb47e69..2632e93493 100644
--- a/src/pl/plpython/plpython.c
+++ b/src/pl/plpython/plpython.c
@@ -29,7 +29,7 @@
  * MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
  *
  * IDENTIFICATION
- *	$PostgreSQL: pgsql/src/pl/plpython/plpython.c,v 1.69 2006/01/09 02:47:09 neilc Exp $
+ *	$PostgreSQL: pgsql/src/pl/plpython/plpython.c,v 1.70 2006/01/10 00:33:12 neilc Exp $
  *
  *********************************************************************
  */
@@ -895,6 +895,7 @@ PLy_function_build_args(FunctionCallInfo fcinfo, PLyProcedure * proc)
 			 * FIXME -- error check this
 			 */
 			PyList_SetItem(args, i, arg);
+			arg = NULL;
 		}
 	}
 	PG_CATCH();