[BUG] Swagger `Try it out` missing parameters when using `include_router` with a url variable in the prefix

Describe the bug When a router is added to an app using include_router, and the prefix parameter contains a url variable (e.g. ‘/{account}/devices’), the variable is not included as a parameter in the swagger documentation.

To Reproduce Steps to reproduce the behavior:

1. Create a router using APIRouter()
2. Add the router to the app using app.include_router with a prefix.
3. Add a url variable to the prefix

app.include_router(
    device_router,
    prefix="/{account}/devices"
)

1. Launch the application and browse to /docs
2. Expand the path and click the Try it out button

Expected behavior When browsing the swagger docs on http://localhost:8080/docs, I want to be able to use the Try it out feature.

Screenshots

Environment:

• OS: [e.g. Linux / macOS]

• FastAPI Version: 0.38.1

• Python version: 3.7

Additional context

[dmontagu]

Yeah this sounds like a bug in the openapi schema generation. Probably worth a check to see if updating to 0.42 fixes it.

[tiangolo]

Thanks for the help here everyone! 👏 🙇

I assume you solved your problem, so thanks for reporting back and closing the issue 👍