Relocate a badly placed Assert in COPY FROM code

david-rowley · david-rowley · commit bd8fe12ef3f7 · 2024-08-17T10:36:23.000+12:00
There's not much point in asserting a pointer isn't NULL after some code has already dereferenced that pointer. Adjust the code so that the Assert occurs before the pointer dereference. The Assert probably has questionable value in the first place, but it seems worth keeping around to document the contract between CopyMultiInsertInfoNextFreeSlot() and its callers. Author: Amul Sul <sulamul@gmail.com> Discussion: https://postgr.es/m/CAAJ_b94hXQzXaJxTLShkxQUgezf_SUxhzX9TH2f-g6gP7bne7g@mail.gmail.com
diff --git a/src/backend/commands/copyfrom.c b/src/backend/commands/copyfrom.c
@@ -597,10 +597,12 @@ CopyMultiInsertInfoNextFreeSlot(CopyMultiInsertInfo *miinfo,
 								ResultRelInfo *rri)
 {
 	CopyMultiInsertBuffer *buffer = rri->ri_CopyMultiInsertBuffer;
-	int			nused = buffer->nused;
+	int			nused;
 
 	Assert(buffer != NULL);
-	Assert(nused < MAX_BUFFERED_TUPLES);
+	Assert(buffer->nused < MAX_BUFFERED_TUPLES);
+
+	nused = buffer->nused;
 
 	if (buffer->slots[nused] == NULL)
 		buffer->slots[nused] = table_slot_create(rri->ri_RelationDesc, NULL);
