Prerequisites

• Search the current open issues

What are you trying to do that currently feels hard or impossible?

The current library provides an allowedValues list, which is perfect for "allow-listing" defining a small, finite set of values that are acceptable for a parameter.

However, there is no simple way to support "deny-listing" defining a small set of values that are unacceptable, while allowing all other values of that type.

Use Case: I have two common scenarios that are currently difficult to implement:

• I want to define a parameter that accepts any integer except 12345.

• I want to define a user parameter that accepts any username except 'admin' or 'root'.

Current allowedValues (Impossible): For the integer case, I would have to list every other integer [...12344, 12346, ...], which is infinite and not possible.

Current regex (Difficult/Fragile): This is the only workaround but this requires a negative lookahead, which is not supported (e.g., ^(?!12345$)\d+$) or ^(?!(admin|root)$).*$).

This limitation makes it difficult to implement common validation rules.

Suggested Solution(s)

I propose introducing a new excludeValues parameter. This parameter would be a list of items that are explicitly forbidden.

To make this feature powerful and flexible, an item in the excludeValues list could be either a literal value OR a regex string.

Alternatives Considered

No response

Additional Details

No response