[Question] Handling empty query params

I am using Tapir in combination with an HTMX frontend.
Sending a GET request from an input field, HTMX will include the input as a query parameter, even if the value is empty, in some cases - it seems like this is purposefully replicating HTML form behavior.
E.g., I have a date input and use the date pickers "clear" button to reset the value. HTMX will issue a request to mypath?date=.
Tapir does not like this, I get a 400 - Invalid value for: query parameter date.

My endpoint looks something like this:

baseSiteEndpoint.get
      .in(header[Option[Boolean]]("HX-Request"))
      .in("mypath")
      .in(query[Option[LocalDate]]("date"))

I would have expected this to yield a None. My IDE suggests, that this query param uses Codec.listHeadOption and I assume with Codec.localDate as underlying codec.
This seems to try to do something similar to strings.map(LocalDate.parse).headOption, in the sense that the LocalDate.parse fails bc. it might receive an empty string.

This does not work:

  implicit val localDateOpt: Codec[String, Option[LocalDate], TextPlain] =
    Codec.string.map(s => if (s.isEmpty) None else Some(LocalDate.parse(s)))(o => o.map(DateTimeFormatter.ISO_LOCAL_DATE.format).getOrElse(""))
      .schema(Schema.schemaForLocalDate.asOption)

I don't understand the codec selection fully, so I'm a bit at a loss.
Also, I wonder if this behavior by Tapir is correct? It seems like many servers do accept query params of that sort?

Tapir version: 1.10.10
Scala version: 2.13.14

Start by reproducing the endpoint with the query string ?date= and trace how query[Option[LocalDate]]("date") selects and applies its codec. Compare that behavior with the supplied custom codec and determine whether an empty value should decode as None; done means the behavior is clarified or corrected and covered by an appropriate test.