New Vercel adapter generates conflicting lambda functions for routes with same filename but different directories

[slawekkolodziej]

Astro Info

Astro                    v3.0.8
Node                     v18.14.2
System                   macOS (arm64)
Package Manager          yarn
Output                   hybrid
Adapter                  @astrojs/vercel/serverless
Integrations             @astrojs/tailwind
                         @astrojs/svelte

If this issue only occurs in one browser, which browser is a problem?

No response

Describe the Bug

New version of vercel adapter can generate invalid output if two routes have the same file name, but different directory structure.

Consider the structure of pages directory below. In some lines I added vercel function names generated by the adapter:

├── index.astro      // -> entry.index.astro.func
├── 404.astro        // -> entry.404.astro.func
├── share
│   └── [id].astro   // -> entry._id_.astro.func
├── api
    ├── secrets.ts   // -> entry.secrets.astro.func
    └── secrets
        └── [id].ts  // -> entry._id_.astro.func <- this route produces the same vercel func name as share/[id].astro

For each page Vercel adapter is going to build a separate route handler. However, their names may conflict with each other, producing invalid output.

What's the expected result?

I would expect each route to produce separate lambda function.

I narrowed the problem down to this line in Vercel adapter:
https://github.com/withastro/astro/blob/main/packages/integrations/vercel/src/serverless/adapter.ts#L211

It generates function's directory name based on the file name only. I assume this will brake for every route with the same file names nested in different directories.

I can create PR soon.

Link to Minimal Reproducible Example

https://github.com/slawekkolodziej/secretsecret

Participation

• I am willing to submit a pull request for this issue.