FetchResponse objects for a response with multiple of the same HTTP header ignore all but the last value

[catgirlinspace]

HTTP allows for the same header to be sent multiple times. This is often used for Set-Cookie and Link in my experience.

Repro:

% lune
Lune v0.7.8
> print(require("@lune/net").request("https://news.indieweb.org/en").headers)
{
    ["set-cookie"] = "PHPSESSID=aVeryCoolSessionId; path=/",
    ["cache-control"] = "no-store, no-cache, must-revalidate",
    expires = "Thu, 19 Nov 1981 08:52:00 GMT",
    link = "<https://switchboard.p3k.io/>; rel=\"hub\"",
    date = "Wed, 18 Oct 2023 04:10:54 GMT",
    pragma = "no-cache",
    ["content-type"] = "text/html; charset=UTF-8",
    server = "nginx/1.24.0",
}

When making the same request in a browser, the DevTools show several Link headers.

[catgirlinspace]

Personally, I wouldn't call this an enhancement. It's definitely a bug. Information from the response is being removed when it should not be.

[filiptibell]

Personally, I wouldn't call this an enhancement. It's definitely a bug. Information from the response is being removed when it should not be.

I agree that we should lift this limitation but it's not really a bug since it was intentional - both headers and query parameters are simple string -> string maps since at the time of implementation it wasn't clear what to do about multi-values, and nobody had a use case for them just yet.

[filiptibell]

Added support for this in c9ce297