undefined params within getStaticPaths cause Vercel build to fail

[joe-bell]

What version of astro are you using?

2.0.0

Are you using an SSR adapter? If so, which one?

Vercel

What package manager are you using?

pnpm

What operating system are you using?

Mac

Describe the Bug

Expectation

When using params in a getStaticPaths function, I would expect undefined to result in the creation of an index route.

Actual Behaviour

The build fails in Vercel

Success: Without undefined params

• Deployment: https://vercel.com/joebell/astro-bug-params-undefined/4G9AqahtnJTsvXzCP6Z97H55ze73

19:36:18.324	▶ src/pages/example/[...slug].astro
19:36:18.345	  ├─ /example/one/index.html (+21ms)
19:36:18.347	  ├─ /example/two/index.html (+23ms)
19:36:18.348	  └─ /example/three/index.html (+25ms)
19:36:18.349	λ src/pages/api/example/[...slug].ts
19:36:18.350	  ├─ /api/example/one (+1ms)
19:36:18.351	  ├─ /api/example/two (+2ms)
19:36:18.351	  └─ /api/example/three (+3ms)
19:36:18.351	Completed in 59ms.

Error: With undefined params

• Deployment: https://vercel.com/joebell/astro-bug-params-undefined/Fj1im5wqsKA6XdVn2VhGkWrkSFja

▶ src/pages/example/[...slug].astro
19:39:10.815	  ├─ /example/one/index.html (+18ms)
19:39:10.817	  ├─ /example/two/index.html (+19ms)
19:39:10.818	  ├─ /example/three/index.html (+21ms)
19:39:10.820	  └─ /example/index.html (+22ms)
19:39:10.820	λ src/pages/api/example/[...slug].ts
19:39:10.821	  ├─ /api/example/one (+1ms)
19:39:10.822	  ├─ /api/example/two (+2ms)
19:39:10.822	  ├─ /api/example/three (+3ms)
19:39:10.911	 error   EISDIR: illegal operation on a directory, open '/vercel/path0/.vercel/output/static/api/example'
19:39:10.911	Error: EISDIR: illegal operation on a directory, open '/vercel/path0/.vercel/output/static/api/example'
19:39:10.926	 ELIFECYCLE  Command failed with exit code 1.

Link to Minimal Reproducible Example

https://github.com/joe-bell/astro-bug-params-undefined

Note

More details have been provided in the reproduction

Participation

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

---

Not part of the template, but just want to say a huge thanks to the Astro team – I love using this product and I appreciate you all!

[AirBorne04]

Ok there seems to be an inconsistency with the behaviour between API routes and Pages where for Pages undefined is translated into index, for the API routes undefined is throwing an error and not falling back to index.
The easy work around would be to add index for the API route directly.

[joe-bell]

Cheers! That’s the tactic I’ve opted for now; with a _handler.ts that’s used across both index.ts and […slug].ts

It’s fine in the meantime, but of course would be nice to have matching behaviour across all routes

[joe-bell]

Following up: It seems like this workaround unfortunately doesn't work

The index.ts builds, but the [slug] or [...slug] doesn't:

λ src/pages/example/index.ts
--
17:26:26.181 | └─ /assets/example (+16ms)
17:26:26.181 | λ src/pages/example/[slug].ts
17:26:26.495 | error   ENOTDIR: not a directory, mkdir '/vercel/path0/.vercel/output/static/example/'

[AirBorne04]

Sorry I might not have been clear on what I meant exactly, you do not need to create a separate index.ts.

My suggestion was to replace this line:

const slugs = ["one", "two", "three", undefined];

with the following

const slugs = ["one", "two", "three", "index"];

[joe-bell]

Thanks @AirBorne04!

That seems to work for endpoints, but not for regular pages

joe-bell/astro-bug-params-undefined#1

• https://astro-bug-params-undefined-cspzja1z6-joebell.vercel.app/example/index
• https://astro-bug-params-undefined-cspzja1z6-joebell.vercel.app/example (this one doesn't exist)
• https://astro-bug-params-undefined-cspzja1z6-joebell.vercel.app/api/example
• https://astro-bug-params-undefined-cspzja1z6-joebell.vercel.app/api/example/index

[AirBorne04]

Hi @joe-bell,
it seems that example/works just example not. I would like to dig deeper on this one, but I do not have time at the moment.
@matthewp can you check this out?

[JerryWu1234]

Thanks @AirBorne04!

That seems to work for endpoints, but not for regular pages

joe-bell/astro-bug-params-undefined#1

• https://astro-bug-params-undefined-cspzja1z6-joebell.vercel.app/example/index
• https://astro-bug-params-undefined-cspzja1z6-joebell.vercel.app/example (this one doesn't exist)
• https://astro-bug-params-undefined-cspzja1z6-joebell.vercel.app/api/example
• https://astro-bug-params-undefined-cspzja1z6-joebell.vercel.app/api/example/index

i wan to check out, but I feel like i'm missing out on something.
this link of code all from this https://github.com/joe-bell/astro-bug-params-undefined repository？