"bad interpreter: No such file or directory" error if virtual env is in a folder with whitespaces

[ulf1]

replicate the error

(1) install a virtual env in a folder with whitespaces

mkdir -p "${HOME}/folder with whitespaces/"
cd "${HOME}/folder with whitespaces/"

python3 -m venv .venv
source .venv/bin/activate
pip install uvicorn fastapi

(2) main.py

from fastapi import FastAPI
app = FastAPI()
@app.get("/")
def read_root():
    return {"Hello": "World"}

(3) Try to start server

uvicorn main:app --reload

Error message

-bash: /Users/uh/folder with whitespaces/.venv/bin/uvicorn: "/Users/uh/folder: bad interpreter: No such file or directory

my guess

I guess you are using something like

filepath=${filepath}

instead of

filepath="${filepath}"

somewhere

[tomchristie]

This didn't replicate for me.
The "bad interpreter" error makes it look like a shell issue occuring before the python interpreter/uvicorn is even started.

[ulf1]

It might depend on the computer used.
I use MacOS.

I replicated the error in a debian docker container too.
https://github.com/ulf1/bugreport-uvicorn

Feel free to try it with any other OS.

[tomchristie]

Right, but what you’re showing me there isn’t a Python traceback. Not at all clear that it’s a uvicorn issue rather than some other environment problem. It’d be worth installing other python based command line tools too, and trying those for comparison.

[ulf1]

The cause of the problem is a shebang with whitespaces.
If you install a virtual env in a folder with whitespace,
and install uvicorn into the this virtual env,
then the ../bin/uvicorn script would have shebang like this.

#!"/Users/usernamename/folder with whitespaces/venvname/bin/python3"
...

It seems that the python project had this issue for years (see virtualenv, issue 53) and fixed it somehow.

[tomchristie]

Ok, thanks. That script isn’t related by uvicorn. You might want to make sure you’ve got recent pip and virtual events versions.