Repair bug #2839: the various ExecReScan functions need to reset

ps_TupFromTlist in plan nodes that make use of it.  This was being done
correctly in join nodes and Result nodes but not in any relation-scan nodes.
Bug would lead to bogus results if a set-returning function appeared in the
targetlist of a subquery that could be rescanned after partial execution,
for example a subquery within EXISTS().  Bug has been around forever :-(
... surprising it wasn't reported before.

src/backend/executor/nodeBitmapHeapscan.c

@@ -21,7 +21,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/executor/nodeBitmapHeapscan.c,v 1.14 2006/10/04 00:29:52 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/executor/nodeBitmapHeapscan.c,v 1.15 2006/12/26 19:26:45 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -364,6 +364,8 @@ ExecBitmapHeapReScan(BitmapHeapScanState *node, ExprContext *exprCtxt)
 	estate = node->ss.ps.state;
 	scanrelid = ((BitmapHeapScan *) node->ss.ps.plan)->scan.scanrelid;
 
+	node->ss.ps.ps_TupFromTlist = false;
+
 	/*
 	 * If we are being passed an outer tuple, link it into the "regular"
 	 * per-tuple econtext for possible qual eval.
@@ -488,6 +490,8 @@ ExecInitBitmapHeapScan(BitmapHeapScan *node, EState *estate, int eflags)
 	 */
 	ExecAssignExprContext(estate, &scanstate->ss.ps);
 
+	scanstate->ss.ps.ps_TupFromTlist = false;
+
 	/*
 	 * initialize child expressions
 	 */

src/backend/executor/nodeFunctionscan.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/executor/nodeFunctionscan.c,v 1.40 2006/06/27 02:51:39 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/executor/nodeFunctionscan.c,v 1.41 2006/12/26 19:26:45 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -317,6 +317,7 @@ void
 ExecFunctionReScan(FunctionScanState *node, ExprContext *exprCtxt)
 {
 	ExecClearTuple(node->ss.ps.ps_ResultTupleSlot);
+	node->ss.ps.ps_TupFromTlist = false;
 
 	/*
 	 * If we haven't materialized yet, just return.

src/backend/executor/nodeIndexscan.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/executor/nodeIndexscan.c,v 1.118 2006/12/23 00:43:09 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/executor/nodeIndexscan.c,v 1.119 2006/12/26 19:26:45 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -168,6 +168,8 @@ ExecIndexReScan(IndexScanState *node, ExprContext *exprCtxt)
 	econtext = node->iss_RuntimeContext;		/* context for runtime keys */
 	scanrelid = ((IndexScan *) node->ss.ps.plan)->scan.scanrelid;
 
+	node->ss.ps.ps_TupFromTlist = false;
+
 	if (econtext)
 	{
 		/*
@@ -476,6 +478,8 @@ ExecInitIndexScan(IndexScan *node, EState *estate, int eflags)
 	 */
 	ExecAssignExprContext(estate, &indexstate->ss.ps);
 
+	indexstate->ss.ps.ps_TupFromTlist = false;
+
 	/*
 	 * initialize child expressions
 	 *

src/backend/executor/nodeResult.c

@@ -38,7 +38,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/executor/nodeResult.c,v 1.34 2006/03/05 15:58:26 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/executor/nodeResult.c,v 1.35 2006/12/26 19:26:45 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -200,6 +200,8 @@ ExecInitResult(Result *node, EState *estate, int eflags)
 	 */
 	ExecAssignExprContext(estate, &resstate->ps);
 
+	resstate->ps.ps_TupFromTlist = false;
+
 #define RESULT_NSLOTS 1
 
 	/*

src/backend/executor/nodeSeqscan.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/executor/nodeSeqscan.c,v 1.61 2006/10/04 00:29:52 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/executor/nodeSeqscan.c,v 1.62 2006/12/26 19:26:46 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -295,6 +295,8 @@ ExecSeqReScan(SeqScanState *node, ExprContext *exprCtxt)
 	estate = node->ps.state;
 	scanrelid = ((SeqScan *) node->ps.plan)->scanrelid;
 
+	node->ps.ps_TupFromTlist = false;
+
 	/* If this is re-scanning of PlanQual ... */
 	if (estate->es_evTuple != NULL &&
 		estate->es_evTuple[scanrelid - 1] != NULL)

src/backend/executor/nodeSubqueryscan.c

@@ -12,7 +12,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/executor/nodeSubqueryscan.c,v 1.32 2006/10/04 00:29:53 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/executor/nodeSubqueryscan.c,v 1.33 2006/12/26 19:26:46 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -294,4 +294,5 @@ ExecSubqueryReScan(SubqueryScanState *node, ExprContext *exprCtxt)
 	MemoryContextSwitchTo(oldcontext);
 
 	node->ss.ss_ScanTupleSlot = NULL;
+	node->ss.ps.ps_TupFromTlist = false;
 }

src/backend/executor/nodeTidscan.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/executor/nodeTidscan.c,v 1.51 2006/10/04 00:29:53 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/executor/nodeTidscan.c,v 1.52 2006/12/26 19:26:46 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -376,6 +376,8 @@ ExecTidReScan(TidScanState *node, ExprContext *exprCtxt)
 	estate = node->ss.ps.state;
 	scanrelid = ((TidScan *) node->ss.ps.plan)->scan.scanrelid;
 
+	node->ss.ps.ps_TupFromTlist = false;
+
 	/* If we are being passed an outer tuple, save it for runtime key calc */
 	if (exprCtxt != NULL)
 		node->ss.ps.ps_ExprContext->ecxt_outertuple =
@@ -482,6 +484,8 @@ ExecInitTidScan(TidScan *node, EState *estate, int eflags)
 	 */
 	ExecAssignExprContext(estate, &tidstate->ss.ps);
 
+	tidstate->ss.ps.ps_TupFromTlist = false;
+
 	/*
 	 * initialize child expressions
 	 */

src/backend/executor/nodeValuesscan.c

@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/executor/nodeValuesscan.c,v 1.3 2006/10/04 00:29:53 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/executor/nodeValuesscan.c,v 1.4 2006/12/26 19:26:46 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -334,6 +334,7 @@ void
 ExecValuesReScan(ValuesScanState *node, ExprContext *exprCtxt)
 {
 	ExecClearTuple(node->ss.ps.ps_ResultTupleSlot);
+	node->ss.ps.ps_TupFromTlist = false;
 
 	node->curr_idx = -1;
 }