Add defenses against trying to attach qual conditions to a setOperation

query node, since that won't work unless the planner is upgraded.
Someday we should try to support at least some cases of this, but for
now just plug the hole in the dike.  Per discussion with Dmitry Tkach.

Author: tglsfdc

src/backend/optimizer/prep/prepunion.c

@@ -14,7 +14,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/optimizer/prep/prepunion.c,v 1.97 2003/06/29 23:05:04 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/optimizer/prep/prepunion.c,v 1.98 2003/07/16 17:25:48 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -85,6 +85,14 @@ plan_set_operations(Query *parse)
 
 	Assert(topop && IsA(topop, SetOperationStmt));
 
+	/* check for unsupported stuff */
+	Assert(parse->utilityStmt == NULL);
+	Assert(parse->jointree->fromlist == NIL);
+	Assert(parse->jointree->quals == NULL);
+	Assert(parse->groupClause == NIL);
+	Assert(parse->havingQual == NULL);
+	Assert(parse->distinctClause == NIL);
+
 	/*
 	 * Find the leftmost component Query.  We need to use its column names
 	 * for all generated tlists (else SELECT INTO won't work right).

src/backend/parser/analyze.c

@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- *	$Header: /cvsroot/pgsql/src/backend/parser/analyze.c,v 1.278 2003/07/03 19:07:30 tgl Exp $
+ *	$Header: /cvsroot/pgsql/src/backend/parser/analyze.c,v 1.279 2003/07/16 17:25:48 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1787,6 +1787,15 @@ transformRuleStmt(ParseState *pstate, RuleStmt *stmt,
 			 */
 			sub_qry = getInsertSelectQuery(top_subqry, NULL);
 
+			/*
+			 * If the sub_qry is a setop, we cannot attach any qualifications
+			 * to it, because the planner won't notice them.  This could
+			 * perhaps be relaxed someday, but for now, we may as well reject
+			 * such a rule immediately.
+			 */
+			if (sub_qry->setOperations != NULL && stmt->whereClause != NULL)
+				elog(ERROR, "Conditional UNION/INTERSECT/EXCEPT statements are not implemented");
+
 			/*
 			 * Validate action's use of OLD/NEW, qual too
 			 */
@@ -1841,6 +1850,13 @@ transformRuleStmt(ParseState *pstate, RuleStmt *stmt,
 			 */
 			if (has_old || (has_new && stmt->event == CMD_UPDATE))
 			{
+				/*
+				 * If sub_qry is a setop, manipulating its jointree will do
+				 * no good at all, because the jointree is dummy.  (This
+				 * should be a can't-happen case because of prior tests.)
+				 */
+				if (sub_qry->setOperations != NULL)
+					elog(ERROR, "Conditional UNION/INTERSECT/EXCEPT statements are not implemented");
 				/* hack so we can use addRTEtoQuery() */
 				sub_pstate->p_rtable = sub_qry->rtable;
 				sub_pstate->p_joinlist = sub_qry->jointree->fromlist;

src/backend/rewrite/rewriteHandler.c

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteHandler.c,v 1.122 2003/07/03 16:34:25 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteHandler.c,v 1.123 2003/07/16 17:25:48 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -148,18 +148,31 @@ rewriteRuleAction(Query *parsetree,
 	 * As above, the action's jointree must not share substructure with the
 	 * main parsetree's.
 	 */
-	if (sub_action->jointree != NULL)
+	if (sub_action->commandType != CMD_UTILITY)
 	{
 		bool		keeporig;
 		List	   *newjointree;
 
+		Assert(sub_action->jointree != NULL);
 		keeporig = (!rangeTableEntry_used((Node *) sub_action->jointree,
 										  rt_index, 0)) &&
 			(rangeTableEntry_used(rule_qual, rt_index, 0) ||
 		  rangeTableEntry_used(parsetree->jointree->quals, rt_index, 0));
 		newjointree = adjustJoinTreeList(parsetree, !keeporig, rt_index);
-		sub_action->jointree->fromlist =
-			nconc(newjointree, sub_action->jointree->fromlist);
+		if (newjointree != NIL)
+		{
+			/*
+			 * If sub_action is a setop, manipulating its jointree will do
+			 * no good at all, because the jointree is dummy.  (Perhaps
+			 * someday we could push the joining and quals down to the
+			 * member statements of the setop?)
+			 */
+			if (sub_action->setOperations != NULL)
+				elog(ERROR, "Conditional UNION/INTERSECT/EXCEPT statements are not implemented");
+
+			sub_action->jointree->fromlist =
+				nconc(newjointree, sub_action->jointree->fromlist);
+		}
 	}
 
 	/*

src/backend/rewrite/rewriteManip.c

@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteManip.c,v 1.72 2003/06/06 15:04:02 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteManip.c,v 1.73 2003/07/16 17:25:48 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -733,6 +733,16 @@ AddQual(Query *parsetree, Node *qual)
 			elog(ERROR, "Conditional utility statements are not implemented");
 	}
 
+	if (parsetree->setOperations != NULL)
+	{
+		/*
+		 * There's noplace to put the qual on a setop statement, either.
+		 * (This could be fixed, but right now the planner simply ignores
+		 * any qual condition on a setop query.)
+		 */
+		elog(ERROR, "Conditional UNION/INTERSECT/EXCEPT statements are not implemented");
+	}
+
 	/* INTERSECT want's the original, but we need to copy - Jan */
 	copy = copyObject(qual);
 
@@ -773,6 +783,16 @@ AddHavingQual(Query *parsetree, Node *havingQual)
 			elog(ERROR, "Conditional utility statements are not implemented");
 	}
 
+	if (parsetree->setOperations != NULL)
+	{
+		/*
+		 * There's noplace to put the qual on a setop statement, either.
+		 * (This could be fixed, but right now the planner simply ignores
+		 * any qual condition on a setop query.)
+		 */
+		elog(ERROR, "Conditional UNION/INTERSECT/EXCEPT statements are not implemented");
+	}
+
 	/* INTERSECT want's the original, but we need to copy - Jan */
 	copy = copyObject(havingQual);