Optional list query parameter defaults to list with a single element

[mancze]

Expected Behavior

Query parameter defined as @QueryValue(value = "v", defaultValue = "") List<String> values should default to an empty list when parameter is not present. This was working in Micronaut 3, but doesn't in Micronaut 4.

Alternatively, there should be a documented way how to declare such parameter if this syntax turns out to be insufficient (e.g. to be able to distinguish between ?v= (parameter specified, but without value) vs ? (no parameter specified).

Actual Behaviour

List with a single element of an empty string is passed as an argument.

Steps To Reproduce

1. Run example app
2. Execute curl http://localhost:8080/list-nullable
3. Expected output (empty list is passed to the method):

values == null: false
values: []
values.size(): 0

Environment Information

No response

Example Application

https://github.com/mancze/micronaut-sandbox/tree/repro/optional-list-query-parameter

Version

4.3.8