feat: adapter-vercel should generate sourcemaps

[ACHP]

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Tests

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Why

This pull-request adds a new option to enable sourcemap for the generated build. This is really important for error monitoring integration. (eg; Sentry in my case).
For now there is no easy way to debug a production app deployed with sveltkit on vercel.

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🦋 Changeset detected

Latest commit: 9cd0a34

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@sveltejs/adapter-vercel	Patch

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[Rich-Harris]

Thank you! Is there any reason to make this optional? Why wouldn't we always generate it?

[benmccann]

We probably should always generate sourcemaps, but I wonder what the default should be. It's not a simple boolean but an enum. To generate them as separate files probably is a good default, but I could see people wanting something different

[Rich-Harris]

I could see people wanting something different

I can't. I think we should just always do linked sourcemaps (i.e. true) — if someone comes up with a compelling rationale for exposing an option, we could easily add it in a non-breaking way in future, but until then I think we should abide by the principle that configuration is a last resort

[benmccann]

Making it linked until someone needs something else sounds like a fine solution to me

[ACHP]

Thank you for your reviews, I updated this PR according to your comments. However the CI seems broken on Windows but I don't think it's related to this pull-request

[benmccann]

I reran the Windows CI and it passed. I wouldn't worry if it's only one test job that fails. We have some flaky tests

[benmccann]

My one other question is whether we also need to make the same change to the other adapters that use esbuild. I'm guessing we probably do, but haven't checked

[ACHP]

My one other question is whether we also need to make the same change to the other adapters that use esbuild. I'm guessing we probably do, but haven't checked

Yes, there is no reason not to do it on other adapters I guess. I did it on the vercel adapter because this is what I'm working on at the moment and it's easy for me to test it, so I'm was confident enought to do it. Do you think other adapters should be updated in this PR as well or should we merge it as is and create other pull-request for different adapters ?

[benmccann]

I'd rather we just do them all in this PR if you don't mind updating it. Only a few of the adapters use esbuild, so hopefully there won't be too much to update.

[8462852]

I think this should be configurable (on by default). Reason: Source code protection. I know a large company that uses kit in production that needs this option.

[benmccann]

You don't have to provide the source maps to anyone outside your company, so I don't see that as a reason to make it configurable

[8462852]

You don't have to provide the source maps to anyone outside your company, so I don't see that as a reason to make it configurable

Ok thanks. I just don't understand how I could prevent to ship source maps in the current proposal. Would I need to fork the Vercel adapter?

[Rich-Harris]

@8462852 to be clear, we're only talking about sourcemaps for your serverless/edge functions. The sourcemapped stack traces will not be visible to anyone who doesn't have access to https://vercel.com/YOUR_ORG/YOUR_PROJECT/YOUR_DEPLOYMENT_ID/functions?name=YOUR_FUNCTION

[Rich-Harris]

thank you!