A restriction by list is chosen by which mistake would go unnoticed
Where a rule restricts something by a list, it says whether the list names what is allowed or what is forbidden, and chooses by which mistake would go unnoticed: where something left out would go unnoticed, the list names what is forbidden, as the records a backup leaves out; where something let in would go unnoticed, it names what is allowed, as the fields a public API returns.
A list goes wrong on whatever nobody thought of when it was written: one naming what is allowed shuts out every newcomer, one naming what is forbidden lets every newcomer in, and for a given restriction only one of those two mistakes is noticed.
The links it makes
The decisions taken on it
- Problem
Its examples were drawn from one project a reader of the method does not know.
- Ruling
The owner: the examples name what any system has — a user, an operator, a record, a request — and nothing of one implementation; the worked example's subject stays in the example.
- Problem
The rule spoke of sets, where what a rule does is restrict something by a list, and spent its words on what everyone knows of allow-lists and deny-lists rather than on how to choose between them.
- Ruling
The owner: it speaks of a restriction by list and keeps the criterion for choosing one.