Revert "Get rid of the "new" and "old" entries in a view's rangetable."

This reverts commit 1b4d280ea1eb7ddb2e16654d5fa16960bb959566.
It's broken the buildfarm members that run cross-version-upgrade tests,
because they're not prepared to deal with cosmetic differences between
CREATE VIEW commands emitted by older servers and HEAD.  Even if we had
a solution to that, which we don't, it'd take some time to roll it out
to the affected animals.  This improvement isn't valuable enough to
justify addressing that problem on an emergency basis, so revert it
for now.

9 files changed, 165 insertions, 41 deletions

diff --git a/src/backend/commands/lockcmds.c b/src/backend/commands/lockcmds.c
index 9755d6ed13f..99e68bff85d 100644
--- a/src/backend/commands/lockcmds.c
+++ b/src/backend/commands/lockcmds.c
@@ -194,6 +194,15 @@ LockViewRecurse_walker(Node *node, LockViewRecurse_context *context)
 			char		relkind = rte->relkind;
 			char	   *relname = get_rel_name(relid);
 
+			/*
+			 * The OLD and NEW placeholder entries in the view's rtable are
+			 * skipped.
+			 */
+			if (relid == context->viewoid &&
+				(strcmp(rte->eref->aliasname, "old") == 0 ||
+				 strcmp(rte->eref->aliasname, "new") == 0))
+				continue;
+
 			/* Currently, we only allow plain tables or views to be locked. */
 			if (relkind != RELKIND_RELATION && relkind != RELKIND_PARTITIONED_TABLE &&
 				relkind != RELKIND_VIEW)
diff --git a/src/backend/commands/view.c b/src/backend/commands/view.c
index ff98c773f55..0bacb819e52 100644
--- a/src/backend/commands/view.c
+++ b/src/backend/commands/view.c
@@ -353,6 +353,107 @@ DefineViewRules(Oid viewOid, Query *viewParse, bool replace)
 	 */
 }
 
+/*---------------------------------------------------------------
+ * UpdateRangeTableOfViewParse
+ *
+ * Update the range table of the given parsetree.
+ * This update consists of adding two new entries IN THE BEGINNING
+ * of the range table (otherwise the rule system will die a slow,
+ * horrible and painful death, and we do not want that now, do we?)
+ * one for the OLD relation and one for the NEW one (both of
+ * them refer in fact to the "view" relation).
+ *
+ * Of course we must also increase the 'varnos' of all the Var nodes
+ * by 2...
+ *
+ * These extra RT entries are not actually used in the query,
+ * except for run-time locking.
+ *---------------------------------------------------------------
+ */
+static Query *
+UpdateRangeTableOfViewParse(Oid viewOid, Query *viewParse)
+{
+	Relation	viewRel;
+	List	   *new_rt;
+	ParseNamespaceItem *nsitem;
+	RangeTblEntry *rt_entry1,
+			   *rt_entry2;
+	RTEPermissionInfo *rte_perminfo1;
+	ParseState *pstate;
+	ListCell   *lc;
+
+	/*
+	 * Make a copy of the given parsetree.  It's not so much that we don't
+	 * want to scribble on our input, it's that the parser has a bad habit of
+	 * outputting multiple links to the same subtree for constructs like
+	 * BETWEEN, and we mustn't have OffsetVarNodes increment the varno of a
+	 * Var node twice.  copyObject will expand any multiply-referenced subtree
+	 * into multiple copies.
+	 */
+	viewParse = copyObject(viewParse);
+
+	/* Create a dummy ParseState for addRangeTableEntryForRelation */
+	pstate = make_parsestate(NULL);
+
+	/* need to open the rel for addRangeTableEntryForRelation */
+	viewRel = relation_open(viewOid, AccessShareLock);
+
+	/*
+	 * Create the 2 new range table entries and form the new range table...
+	 * OLD first, then NEW....
+	 */
+	nsitem = addRangeTableEntryForRelation(pstate, viewRel,
+										   AccessShareLock,
+										   makeAlias("old", NIL),
+										   false, false);
+	rt_entry1 = nsitem->p_rte;
+	rte_perminfo1 = nsitem->p_perminfo;
+	nsitem = addRangeTableEntryForRelation(pstate, viewRel,
+										   AccessShareLock,
+										   makeAlias("new", NIL),
+										   false, false);
+	rt_entry2 = nsitem->p_rte;
+
+	/*
+	 * Add only the "old" RTEPermissionInfo at the head of view query's list
+	 * and update the other RTEs' perminfoindex accordingly.  When rewriting a
+	 * query on the view, ApplyRetrieveRule() will transfer the view
+	 * relation's permission details into this RTEPermissionInfo.  That's
+	 * needed because the view's RTE itself will be transposed into a subquery
+	 * RTE that can't carry the permission details; see the code stanza toward
+	 * the end of ApplyRetrieveRule() for how that's done.
+	 */
+	viewParse->rteperminfos = lcons(rte_perminfo1, viewParse->rteperminfos);
+	foreach(lc, viewParse->rtable)
+	{
+		RangeTblEntry *rte = lfirst(lc);
+
+		if (rte->perminfoindex > 0)
+			rte->perminfoindex += 1;
+	}
+
+	/*
+	 * Also make the "new" RTE's RTEPermissionInfo undiscoverable.  This is a
+	 * bit of a hack given that all the non-child RTE_RELATION entries really
+	 * should have a RTEPermissionInfo, but this dummy "new" RTE is going to
+	 * go away anyway in the very near future.
+	 */
+	rt_entry2->perminfoindex = 0;
+
+	new_rt = lcons(rt_entry1, lcons(rt_entry2, viewParse->rtable));
+
+	viewParse->rtable = new_rt;
+
+	/*
+	 * Now offset all var nodes by 2, and jointree RT indexes too.
+	 */
+	OffsetVarNodes((Node *) viewParse, 2, 0);
+
+	relation_close(viewRel, AccessShareLock);
+
+	return viewParse;
+}
+
 /*
  * DefineView
  *		Execute a CREATE VIEW command.
@@ -516,6 +617,12 @@ void
 StoreViewQuery(Oid viewOid, Query *viewParse, bool replace)
 {
 	/*
+	 * The range table of 'viewParse' does not contain entries for the "OLD"
+	 * and "NEW" relations. So... add them!
+	 */
+	viewParse = UpdateRangeTableOfViewParse(viewOid, viewParse);
+
+	/*
 	 * Now create the rules associated with the view.
 	 */
 	DefineViewRules(viewOid, viewParse, replace);
diff --git a/src/backend/nodes/outfuncs.c b/src/backend/nodes/outfuncs.c
index 6b368b08b21..69324d5a9aa 100644
--- a/src/backend/nodes/outfuncs.c
+++ b/src/backend/nodes/outfuncs.c
@@ -512,10 +512,6 @@ _outRangeTblEntry(StringInfo str, const RangeTblEntry *node)
 		case RTE_SUBQUERY:
 			WRITE_NODE_FIELD(subquery);
 			WRITE_BOOL_FIELD(security_barrier);
-			/* we re-use these RELATION fields, too: */
-			WRITE_OID_FIELD(relid);
-			WRITE_INT_FIELD(rellockmode);
-			WRITE_UINT_FIELD(perminfoindex);
 			break;
 		case RTE_JOIN:
 			WRITE_ENUM_FIELD(jointype, JoinType);
@@ -549,11 +545,10 @@ _outRangeTblEntry(StringInfo str, const RangeTblEntry *node)
 		case RTE_NAMEDTUPLESTORE:
 			WRITE_STRING_FIELD(enrname);
 			WRITE_FLOAT_FIELD(enrtuples);
+			WRITE_OID_FIELD(relid);
 			WRITE_NODE_FIELD(coltypes);
 			WRITE_NODE_FIELD(coltypmods);
 			WRITE_NODE_FIELD(colcollations);
-			/* we re-use these RELATION fields, too: */
-			WRITE_OID_FIELD(relid);
 			break;
 		case RTE_RESULT:
 			/* no extra fields */
diff --git a/src/backend/nodes/readfuncs.c b/src/backend/nodes/readfuncs.c
index f3629cdfd14..30cd7a0da6b 100644
--- a/src/backend/nodes/readfuncs.c
+++ b/src/backend/nodes/readfuncs.c
@@ -478,10 +478,6 @@ _readRangeTblEntry(void)
 		case RTE_SUBQUERY:
 			READ_NODE_FIELD(subquery);
 			READ_BOOL_FIELD(security_barrier);
-			/* we re-use these RELATION fields, too: */
-			READ_OID_FIELD(relid);
-			READ_INT_FIELD(rellockmode);
-			READ_UINT_FIELD(perminfoindex);
 			break;
 		case RTE_JOIN:
 			READ_ENUM_FIELD(jointype, JoinType);
@@ -524,11 +520,10 @@ _readRangeTblEntry(void)
 		case RTE_NAMEDTUPLESTORE:
 			READ_STRING_FIELD(enrname);
 			READ_FLOAT_FIELD(enrtuples);
+			READ_OID_FIELD(relid);
 			READ_NODE_FIELD(coltypes);
 			READ_NODE_FIELD(coltypmods);
 			READ_NODE_FIELD(colcollations);
-			/* we re-use these RELATION fields, too: */
-			READ_OID_FIELD(relid);
 			break;
 		case RTE_RESULT:
 			/* no extra fields */
diff --git a/src/backend/optimizer/plan/setrefs.c b/src/backend/optimizer/plan/setrefs.c
index 85ba9d1ca1e..ed9c1e61876 100644
--- a/src/backend/optimizer/plan/setrefs.c
+++ b/src/backend/optimizer/plan/setrefs.c
@@ -405,15 +405,13 @@ add_rtes_to_flat_rtable(PlannerInfo *root, bool recursing)
 	 *
 	 * At top level, we must add all RTEs so that their indexes in the
 	 * flattened rangetable match up with their original indexes.  When
-	 * recursing, we only care about extracting relation RTEs (and subquery
-	 * RTEs that were once relation RTEs).
+	 * recursing, we only care about extracting relation RTEs.
 	 */
 	foreach(lc, root->parse->rtable)
 	{
 		RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
 
-		if (!recursing || rte->rtekind == RTE_RELATION ||
-			(rte->rtekind == RTE_SUBQUERY && OidIsValid(rte->relid)))
+		if (!recursing || rte->rtekind == RTE_RELATION)
 			add_rte_to_flat_rtable(glob, root->parse->rteperminfos, rte);
 	}
 
@@ -503,9 +501,8 @@ flatten_rtes_walker(Node *node, flatten_rtes_walker_context *cxt)
 	{
 		RangeTblEntry *rte = (RangeTblEntry *) node;
 
-		/* As above, we need only save relation RTEs and former relations */
-		if (rte->rtekind == RTE_RELATION ||
-			(rte->rtekind == RTE_SUBQUERY && OidIsValid(rte->relid)))
+		/* As above, we need only save relation RTEs */
+		if (rte->rtekind == RTE_RELATION)
 			add_rte_to_flat_rtable(cxt->glob, cxt->query->rteperminfos, rte);
 		return false;
 	}
@@ -563,8 +560,7 @@ add_rte_to_flat_rtable(PlannerGlobal *glob, List *rteperminfos,
 	glob->finalrtable = lappend(glob->finalrtable, newrte);
 
 	/*
-	 * If it's a plain relation RTE (or a subquery that was once a view
-	 * reference), add the relation OID to relationOids.
+	 * If it's a plain relation RTE, add the table to relationOids.
 	 *
 	 * We do this even though the RTE might be unreferenced in the plan tree;
 	 * this would correspond to cases such as views that were expanded, child
@@ -574,8 +570,7 @@ add_rte_to_flat_rtable(PlannerGlobal *glob, List *rteperminfos,
 	 * Note we don't bother to avoid making duplicate list entries.  We could,
 	 * but it would probably cost more cycles than it would save.
 	 */
-	if (newrte->rtekind == RTE_RELATION ||
-		(newrte->rtekind == RTE_SUBQUERY && OidIsValid(newrte->relid)))
+	if (newrte->rtekind == RTE_RELATION)
 		glob->relationOids = lappend_oid(glob->relationOids, newrte->relid);
 
 	/*
@@ -3408,11 +3403,14 @@ extract_query_dependencies_walker(Node *node, PlannerInfo *context)
 		{
 			RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
 
-			if (rte->rtekind == RTE_RELATION ||
-				(rte->rtekind == RTE_SUBQUERY && OidIsValid(rte->relid)) ||
-				(rte->rtekind == RTE_NAMEDTUPLESTORE && OidIsValid(rte->relid)))
+			if (rte->rtekind == RTE_RELATION)
 				context->glob->relationOids =
 					lappend_oid(context->glob->relationOids, rte->relid);
+			else if (rte->rtekind == RTE_NAMEDTUPLESTORE &&
+					 OidIsValid(rte->relid))
+				context->glob->relationOids =
+					lappend_oid(context->glob->relationOids,
+								rte->relid);
 		}
 
 		/* And recurse into the query's subexpressions */
diff --git a/src/backend/parser/parse_relation.c b/src/backend/parser/parse_relation.c
index b490541f03d..5389a0eddb6 100644
--- a/src/backend/parser/parse_relation.c
+++ b/src/backend/parser/parse_relation.c
@@ -3834,7 +3834,7 @@ addRTEPermissionInfo(List **rteperminfos, RangeTblEntry *rte)
 {
 	RTEPermissionInfo *perminfo;
 
-	Assert(OidIsValid(rte->relid));
+	Assert(rte->rtekind == RTE_RELATION);
 	Assert(rte->perminfoindex == 0);
 
 	/* Nope, so make one and add to the list. */
diff --git a/src/backend/rewrite/rewriteDefine.c b/src/backend/rewrite/rewriteDefine.c
index e36fc72e1ed..52272202881 100644
--- a/src/backend/rewrite/rewriteDefine.c
+++ b/src/backend/rewrite/rewriteDefine.c
@@ -633,6 +633,13 @@ checkRuleResultList(List *targetList, TupleDesc resultDesc, bool isSelect,
  * setRuleCheckAsUser
  *		Recursively scan a query or expression tree and set the checkAsUser
  *		field to the given userid in all RTEPermissionInfos of the query.
+ *
+ * Note: for a view (ON SELECT rule), the checkAsUser field of the OLD
+ * RTE entry's RTEPermissionInfo will be overridden when the view rule is
+ * expanded, and the checkAsUser for the NEW RTE entry's RTEPermissionInfo is
+ * irrelevant because its requiredPerms bits will always be zero.  However, for
+ * other types of rules it's important to set these fields to match the rule
+ * owner.  So we just set them always.
  */
 void
 setRuleCheckAsUser(Node *node, Oid userid)
diff --git a/src/backend/rewrite/rewriteHandler.c b/src/backend/rewrite/rewriteHandler.c
index c74bac20b13..1960dad7013 100644
--- a/src/backend/rewrite/rewriteHandler.c
+++ b/src/backend/rewrite/rewriteHandler.c
@@ -1715,7 +1715,10 @@ ApplyRetrieveRule(Query *parsetree,
 				  List *activeRIRs)
 {
 	Query	   *rule_action;
-	RangeTblEntry *rte;
+	RangeTblEntry *rte,
+			   *subrte;
+	RTEPermissionInfo *perminfo,
+			   *sub_perminfo;
 	RowMarkClause *rc;
 
 	if (list_length(rule->actions) != 1)
@@ -1827,21 +1830,33 @@ ApplyRetrieveRule(Query *parsetree,
 	 * original RTE to a subquery RTE.
 	 */
 	rte = rt_fetch(rt_index, parsetree->rtable);
+	perminfo = getRTEPermissionInfo(parsetree->rteperminfos, rte);
 
 	rte->rtekind = RTE_SUBQUERY;
 	rte->subquery = rule_action;
 	rte->security_barrier = RelationIsSecurityView(relation);
-
-	/*
-	 * Clear fields that should not be set in a subquery RTE.  Note that we
-	 * leave the relid, rellockmode, and perminfoindex fields set, so that the
-	 * view relation can be appropriately locked before execution and its
-	 * permissions checked.
-	 */
+	/* Clear fields that should not be set in a subquery RTE */
+	rte->relid = InvalidOid;
 	rte->relkind = 0;
+	rte->rellockmode = 0;
 	rte->tablesample = NULL;
+	rte->perminfoindex = 0;		/* no permission checking for this RTE */
 	rte->inh = false;			/* must not be set for a subquery */
 
+	/*
+	 * We move the view's permission check data down to its RTEPermissionInfo
+	 * contained in the view query, which the OLD entry in its range table
+	 * points to.
+	 */
+	subrte = rt_fetch(PRS2_OLD_VARNO, rule_action->rtable);
+	Assert(subrte->relid == relation->rd_id);
+	sub_perminfo = getRTEPermissionInfo(rule_action->rteperminfos, subrte);
+	sub_perminfo->requiredPerms = perminfo->requiredPerms;
+	sub_perminfo->checkAsUser = perminfo->checkAsUser;
+	sub_perminfo->selectedCols = perminfo->selectedCols;
+	sub_perminfo->insertedCols = perminfo->insertedCols;
+	sub_perminfo->updatedCols = perminfo->updatedCols;
+
 	return parsetree;
 }
 
@@ -1852,10 +1867,9 @@ ApplyRetrieveRule(Query *parsetree,
  * aggregate.  We leave it to the planner to detect that.
  *
  * NB: this must agree with the parser's transformLockingClause() routine.
- * However, we used to have to avoid marking a view's OLD and NEW rels for
- * updating, which motivated scanning the jointree to determine which rels
- * are used.  Possibly that could now be simplified into just scanning the
- * rangetable as the parser does.
+ * However, unlike the parser we have to be careful not to mark a view's
+ * OLD and NEW rels for updating.  The best way to handle that seems to be
+ * to scan the jointree to determine which rels are used.
  */
 static void
 markQueryForLocking(Query *qry, Node *jtnode,
diff --git a/src/backend/utils/cache/plancache.c b/src/backend/utils/cache/plancache.c
index 77c2ba3f8f4..92f6d5795fc 100644
--- a/src/backend/utils/cache/plancache.c
+++ b/src/backend/utils/cache/plancache.c
@@ -1769,8 +1769,7 @@ AcquireExecutorLocks(List *stmt_list, bool acquire)
 		{
 			RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc2);
 
-			if (!(rte->rtekind == RTE_RELATION ||
-				  (rte->rtekind == RTE_SUBQUERY && OidIsValid(rte->relid))))
+			if (rte->rtekind != RTE_RELATION)
 				continue;
 
 			/*