From d22e47dba8491133c3d5bc2192712dd0ef7de0f7 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Mon, 1 Sep 2008 22:30:48 +0000
Subject: [PATCH] Fix plpgsql's exec_move_row() to supply valid type OIDs to
 exec_assign_value() whenever possible, as per bug report from Oleg Serov. 
 While at it, reorder the operations in the RECORD case to avoid possible
 palloc failure while the variable update is only partly complete.

Back-patch as far as 8.1.  Although the code of the particular function is
similar in 8.0, 8.0's support for composite fields in rows is sufficiently
broken elsewhere that it doesn't seem worth fixing this.
---
 src/pl/plpgsql/src/pl_exec.c | 45 +++++++++++++++++++++---------------
 1 file changed, 27 insertions(+), 18 deletions(-)

diff --git a/src/pl/plpgsql/src/pl_exec.c b/src/pl/plpgsql/src/pl_exec.c
index 3bd3bbd3dd8..74fc6d60335 100644
--- a/src/pl/plpgsql/src/pl_exec.c
+++ b/src/pl/plpgsql/src/pl_exec.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/pl/plpgsql/src/pl_exec.c,v 1.180.2.5 2007/04/19 16:33:32 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/pl/plpgsql/src/pl_exec.c,v 1.180.2.6 2008/09/01 22:30:48 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -4103,13 +4103,27 @@ exec_move_row(PLpgSQL_execstate *estate,
 	if (rec != NULL)
 	{
 		/*
-		 * copy input first, just in case it is pointing at variable's value
+		 * Copy input first, just in case it is pointing at variable's value
 		 */
 		if (HeapTupleIsValid(tup))
 			tup = heap_copytuple(tup);
+		else if (tupdesc)
+		{
+			/* If we have a tupdesc but no data, form an all-nulls tuple */
+			char	   *nulls;
+
+			nulls = (char *) palloc(tupdesc->natts * sizeof(char));
+			memset(nulls, 'n', tupdesc->natts * sizeof(char));
+
+			tup = heap_formtuple(tupdesc, NULL, nulls);
+
+			pfree(nulls);
+		}
+
 		if (tupdesc)
 			tupdesc = CreateTupleDescCopy(tupdesc);
 
+		/* Free the old value ... */
 		if (rec->freetup)
 		{
 			heap_freetuple(rec->tup);
@@ -4121,24 +4135,12 @@ exec_move_row(PLpgSQL_execstate *estate,
 			rec->freetupdesc = false;
 		}
 
+		/* ... and install the new */
 		if (HeapTupleIsValid(tup))
 		{
 			rec->tup = tup;
 			rec->freetup = true;
 		}
-		else if (tupdesc)
-		{
-			/* If we have a tupdesc but no data, form an all-nulls tuple */
-			char	   *nulls;
-
-			nulls = (char *) palloc(tupdesc->natts * sizeof(char));
-			memset(nulls, 'n', tupdesc->natts * sizeof(char));
-
-			rec->tup = heap_formtuple(tupdesc, NULL, nulls);
-			rec->freetup = true;
-
-			pfree(nulls);
-		}
 		else
 			rec->tup = NULL;
 
@@ -4170,6 +4172,7 @@ exec_move_row(PLpgSQL_execstate *estate,
 	 */
 	if (row != NULL)
 	{
+		int			td_natts = tupdesc ? tupdesc->natts : 0;
 		int			t_natts;
 		int			fnum;
 		int			anum;
@@ -4192,12 +4195,18 @@ exec_move_row(PLpgSQL_execstate *estate,
 
 			var = (PLpgSQL_var *) (estate->datums[row->varnos[fnum]]);
 
-			while (anum < t_natts && tupdesc->attrs[anum]->attisdropped)
+			while (anum < td_natts && tupdesc->attrs[anum]->attisdropped)
 				anum++;			/* skip dropped column in tuple */
 
-			if (anum < t_natts)
+			if (anum < td_natts)
 			{
-				value = SPI_getbinval(tup, tupdesc, anum + 1, &isnull);
+				if (anum < t_natts)
+					value = SPI_getbinval(tup, tupdesc, anum + 1, &isnull);
+				else
+				{
+					value = (Datum) 0;
+					isnull = true;
+				}
 				valtype = SPI_gettypeid(tupdesc, anum + 1);
 				anum++;
 			}