Cannot set set-cookie response headers multiple times

[SylvainGarrigues]

Describe the bug

Since the setHeaders takes a POJO and also checks that a response header as not been already set, one cannot set multiple cookies with multiple set-cookie headers.

Reproduction

Source code for setHeaders checks whether an header is already been set, so can’t even call it multiple times.

Logs

No response

System Info

Any system

Severity

serious, but I can work around it

Additional Information

No response

[dummdidumm]

set-cookie is a special case because it's the only header that allows an array input through the setHeaders method. I'd say it's sensible to support that use case and merge the arrays and check no entry appears twice.

[Conduitry]

If this is referring to the load argument setHeaders, the docs do already call that out as a specially handled case https://kit.svelte.dev/docs/load#input-methods-setheaders - I guess it's not actually working that way?

[dummdidumm]

You are right, then it's a bug 😄

[SylvainGarrigues]

My bad, set-cookie is indeed handled as a special case correctly if I pass in an array like the doc says, leading in multiple set-cookie being set. Sorry for the annoyance.

[Conduitry]

It's good that the array version is working, but the docs do say that you should be able to call it multiple times as well. Reopening.

[SylvainGarrigues]

As far as I am concerned, not being able to call it multiple times is not an issue (I prefer the array version), and we could just fix the doc :) But it's not my call to decide. Thanks anyway for your very prompt feedback.