*** a/contrib/file_fdw/file_fdw.c
--- b/contrib/file_fdw/file_fdw.c
***************
*** 408,414 **** get_file_fdw_attribute_options(Oid relid)
  
  	heap_close(rel, AccessShareLock);
  
! 	/* Return DefElem only when some column(s) have force_not_null */
  	if (fnncolumns != NIL)
  		return list_make1(makeDefElem("force_not_null", (Node *) fnncolumns));
  	else
--- 408,415 ----
  
  	heap_close(rel, AccessShareLock);
  
! 	/* Return a list of a single DefElem only when some column(s) have
! 	 * force_not_null */
  	if (fnncolumns != NIL)
  		return list_make1(makeDefElem("force_not_null", (Node *) fnncolumns));
  	else