Modify the parser's error reporting to include a specific hint for the case

of referencing a WITH item that's not yet in scope according to the SQL
spec's semantics.  This seems to be an easy error to make, and the bare
"relation doesn't exist" message doesn't lead one's mind in the correct
direction to fix it.

1 files changed, 71 insertions, 1 deletions

diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index 0fd61fe9cec..79b92b329e1 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/access/heap/heapam.c,v 1.264 2008/09/30 10:52:10 heikki Exp $
+ *	  $PostgreSQL: pgsql/src/backend/access/heap/heapam.c,v 1.265 2008/10/08 01:14:44 tgl Exp $
  *
  *
  * INTERFACE ROUTINES
@@ -1017,6 +1017,45 @@ relation_openrv(const RangeVar *relation, LOCKMODE lockmode)
 }
 
 /* ----------------
+ *		try_relation_openrv - open any relation specified by a RangeVar
+ *
+ *		Same as relation_openrv, but return NULL instead of failing for
+ *		relation-not-found.  (Note that some other causes, such as
+ *		permissions problems, will still result in an ereport.)
+ * ----------------
+ */
+Relation
+try_relation_openrv(const RangeVar *relation, LOCKMODE lockmode)
+{
+	Oid			relOid;
+
+	/*
+	 * Check for shared-cache-inval messages before trying to open the
+	 * relation.  This is needed to cover the case where the name identifies a
+	 * rel that has been dropped and recreated since the start of our
+	 * transaction: if we don't flush the old syscache entry then we'll latch
+	 * onto that entry and suffer an error when we do RelationIdGetRelation.
+	 * Note that relation_open does not need to do this, since a relation's
+	 * OID never changes.
+	 *
+	 * We skip this if asked for NoLock, on the assumption that the caller has
+	 * already ensured some appropriate lock is held.
+	 */
+	if (lockmode != NoLock)
+		AcceptInvalidationMessages();
+
+	/* Look up the appropriate relation using namespace search */
+	relOid = RangeVarGetRelid(relation, true);
+
+	/* Return NULL on not-found */
+	if (!OidIsValid(relOid))
+		return NULL;
+
+	/* Let relation_open do the rest */
+	return relation_open(relOid, lockmode);
+}
+
+/* ----------------
  *		relation_close - close any relation
  *
  *		If lockmode is not "NoLock", we then release the specified lock.
@@ -1097,6 +1136,37 @@ heap_openrv(const RangeVar *relation, LOCKMODE lockmode)
 	return r;
 }
 
+/* ----------------
+ *		try_heap_openrv - open a heap relation specified
+ *		by a RangeVar node
+ *
+ *		As above, but return NULL instead of failing for relation-not-found.
+ * ----------------
+ */
+Relation
+try_heap_openrv(const RangeVar *relation, LOCKMODE lockmode)
+{
+	Relation	r;
+
+	r = try_relation_openrv(relation, lockmode);
+
+	if (r)
+	{
+		if (r->rd_rel->relkind == RELKIND_INDEX)
+			ereport(ERROR,
+					(errcode(ERRCODE_WRONG_OBJECT_TYPE),
+					 errmsg("\"%s\" is an index",
+							RelationGetRelationName(r))));
+		else if (r->rd_rel->relkind == RELKIND_COMPOSITE_TYPE)
+			ereport(ERROR,
+					(errcode(ERRCODE_WRONG_OBJECT_TYPE),
+					 errmsg("\"%s\" is a composite type",
+							RelationGetRelationName(r))));
+	}
+
+	return r;
+}
+
 
 /* ----------------
  *		heap_beginscan	- begin relation scan