Cannot find routes in files containing only `APIRouter()`

[savannahostrowski]

+1, was going to open an issue but since this is already here I went ahead and
created a PR #87 with a fix (tested locally and working).

Root cause: findAllFastAPIFiles() in appDiscovery.ts uses a text pre-filter to avoid running tree-sitter on every Python file. It only checks for "FastAPI(", so files containing only APIRouter() are silently skipped, the downstream parsing pipeline already fully supports APIRouter, the bug is purely in the discovery step.

Originally posted by @NureddinSoltan in #85

[savannahostrowski]

@NureddinSoltan To be clear, you're opening a subdirectory of your FastAPI app, right? If so, I would say this is probably something we cannot support, as the extension heavily relies on the existence of the FastAPI()app instantiation and the project root for pretty much every feature (e.g. search, codelenses, deployment and logs for Cloud, etc). If you open the project up at the level where the app is instantiated, everything should work as expected.

[NureddinSoltan]

Thanks for the clarification! To be clear, I'm opening VS Code at the project root (where pyproject.toml lives), not a subdirectory. My structure is:

project/
├── pyproject.toml
└── backend/
    ├── main.py        # app = FastAPI()
    └── controllers/
        ├── __init__.py   # router = APIRouter() + all include_router calls
        └── items/
            └── items_controller.py  # @router.get(...)

After digging deeper I found two things specific to my project that are likely causing the issue:

1. CBV pattern: my routes are defined inside classes using @cbv(router), with @router.get(...) on methods inside the class rather than on standalone functions. The extension's static analysis only detects top-level decorated functions.

2. 3-level nesting: my router chain goes app --> controllers/__init__.py --> items/__init__.py --> items_controller.py, which is deeper than the typical 2-level pattern.

So maybe this is more of a project-specific limitation than a bug in the extension. Although wherever I defined FASTAPI(), it is detectable instead of APIRoute(), which is kind of weird.

Thanks for your time!

[savannahostrowski]

Thanks for the info, that's helpful context 🙂!

I've tested this out locally and the issue here is with the use of @cbv, which is unsupported and out of scope for the extension. Without the use of the decorator, everything seems to resolve correctly in the structure you've described so there is no other issue outstanding here.

[NureddinSoltan]

Understood, thank you for your time :)