Argument of type '"/example/post-endpoint"' is not assignable to parameter of type 'PathsWithMethod<paths, "post">'

[ViktorPontinen]

Description

A brief description of the bug. Provide either a screenshot or the full error message
When we use the --path-params-as-types flag with openapi-typescript to generate types, some post requests(seems to only affect post requests) stop being autocompleted/discovered and shows error:
Argument of type '"/example/post-endpoint"' is not assignable to parameter of type 'PathsWithMethod<paths, "post">'.

Example(ignore the untyped body):

export const createSomeEntity = async (body) => {
  return client.POST('/example/post-endpoint', {
    body,
  })
}

Without the --path-params-as-types flag, everything works as expected. Only difference I see in generated types is the adjustments to dynamic paths keys: [path: `/example/dynamic/${string}`]:.

Anyone else got same issue or just us?

Reproduction

How can this be reproduced / when did the error occur? Does the issue occur in a specific browser, or all browsers?
Not sure if reproducible in other repos, I guess try to regenerate your types with the --path-params-as-types flag. Will try to test outside our repo to test.

Expected result
I think description covers it's all.
(in case it’s not obvious)

Checklist

• I’m willing to open a PR (see CONTRIBUTING.md)

[kerwanp]

Hi @ViktorPontinen!

Could you provide an OpenAPI schema that result in the same behavior so we can reproduce your issue?

[ViktorPontinen]

Hi @kerwanp , I was finally able to reproduce it in a smaller scope, our real openapi yaml has almost 97k lines and is auto-generated.
While doing so, I also think I figured out why it's happening. Unclear tho if this is because we structure our endpoints incorrectly or if it's just an edge-case that is not covered by openapi-fetch/openapi-typescript.

The paths "/api/sessions/create" and [path: `/api/sessions/${string}`] most likely collide because /create can also match the /${string} path.

Here is repo for reproduction, see /src/services/index.ts: https://github.com/ViktorPontinen/open-api-bug

EDIT: I now see the error is different, give me a minute to push updated.
EDIT TWO: Nvm, will take a while to figure it out. It's something else. Will post when ready.

[ViktorPontinen]

Hi, sorry for the long wait. I was able to narrow it down to the structure of our API, and the error Argument of type 'string' is not assignable to parameter of type 'never'. results in same error as originally reported if there is multiple paths that support the method, which I now added.

Basically if you have a path like /api/foo/{id} that doesn't support PUT/POST(or other), any "child" path like /api/foo/{id}/path-that-supports-put will not be resolved.

Reproduction repo: https://github.com/ViktorPontinen/open-api-bug

Not sure if this something that should be solved on API design level or if open-api typescript/fetch can have built-in support for this structure.

[ViktorPontinen]

Could it be related to microsoft/TypeScript#21760 ? In the PathsWithMethod utility from openapi-typescript-helpers?
Source: https://stackoverflow.com/questions/68869157/unable-to-index-nested-property-of-dynamic-type

[drwpow]

Unfortunately --path-params-as-types isn’t fully-compatible with openapi-fetch, and won’t be. We’d suggest migrating away from the flag to continue using openapi-fetch. The flag may even be deprecated in future versions of openapi-typescript for similar papercuts that people face.