Fix RelationIdGetRelation calls that weren't bothering with error checks.

tglsfdc · tglsfdc · commit deba7c6fc3cc · 2019-09-08T17:00:54.000-04:00
Some of these are quite old, but that doesn't make them not bugs.
We'd rather report a failure via elog than SIGSEGV.

While at it, uniformly spell the error check as !RelationIsValid(rel)
rather than a bare rel == NULL test.  The machine code is the same
but it seems better to be consistent.

Coverity complained about this today, not sure why, because the
mistake is in fact old.
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
@@ -7976,6 +7976,10 @@ ExtractReplicaIdentity(Relation relation, HeapTuple tp, bool key_changed, bool *
 	}
 
 	idx_rel = RelationIdGetRelation(replidindex);
+
+	if (!RelationIsValid(idx_rel))
+		elog(ERROR, "could not open relation with OID %u", replidindex);
+
 	idx_desc = RelationGetDescr(idx_rel);
 
 	/* deform tuple, so we have fast access to columns */
diff --git a/src/backend/replication/logical/reorderbuffer.c b/src/backend/replication/logical/reorderbuffer.c
@@ -1561,7 +1561,7 @@ ReorderBufferCommit(ReorderBuffer *rb, TransactionId xid,
 
 					relation = RelationIdGetRelation(reloid);
 
-					if (relation == NULL)
+					if (!RelationIsValid(relation))
 						elog(ERROR, "could not open relation with OID %u (for filenode \"%s\")",
 							 reloid,
 							 relpathperm(change->data.tp.relnode,
@@ -2969,6 +2969,10 @@ ReorderBufferToastReplace(ReorderBuffer *rb, ReorderBufferTXN *txn,
 	desc = RelationGetDescr(relation);
 
 	toast_rel = RelationIdGetRelation(relation->rd_rel->reltoastrelid);
+	if (!RelationIsValid(toast_rel))
+		elog(ERROR, "could not open relation with OID %u",
+			 relation->rd_rel->reltoastrelid);
+
 	toast_desc = RelationGetDescr(toast_rel);
 
 	/* should we allocate from stack instead? */

Original file line number	Diff line number	Diff line change
`@@ -7976,6 +7976,10 @@ ExtractReplicaIdentity(Relation relation, HeapTuple tp, bool key_changed, bool *`
`7976`	`7976`	`}`
`7977`	`7977`
`7978`	`7978`	`idx_rel = RelationIdGetRelation(replidindex);`
	`7979`	`+`
	`7980`	`+ if (!RelationIsValid(idx_rel))`
	`7981`	`+ elog(ERROR, "could not open relation with OID %u", replidindex);`
	`7982`	`+`
`7979`	`7983`	`idx_desc = RelationGetDescr(idx_rel);`
`7980`	`7984`
`7981`	`7985`	`/* deform tuple, so we have fast access to columns */`