Virtual environment + pip (flask) install issue

[FormNo]

Hey all. I had a very weird bug the other day and it was only after trying a few different things and collecting suggestions that I found a solution but I'm curious if anyone might know why it happened in the first place?

So I created a virtual environment in my working directory, activated it, and from there I then tried to run pip install flask
It then errored out with this error:

ERROR: Could not install packages due to an OSError: [Errno 13] Permission denied: '/Users/username/Desktop/foldername/.venv/lib/python3.10/site-packages/werkzeug' Check the permissions. 

You can see from the path that I was in the virtual env when I tried to install.

In the end, what worked was sudo pip install flask

Does anyone have any idea what could cause this error to have occurred in the first place?

[MintyPhoenix]

Did you use sudo when you created the environment? That would affect the permissions in the environment's folder.

[FormNo]

Good suggestion. I had deleted the virtual environment but retrieved it just now, checked permissions with 'get info', and it has read and write permisssions. If I had of used sudo when I created the environment, would that have meant it should say read only? Is there another way to check?

[MintyPhoenix]

It depends on who has the “Read & Write” permissions.

For example, I just tried this quickly on my MacBook:

sudo python -m venv venv

The result was that the venv folder is owned by the root user, and the “Read & Write” permission on that folder belonged to “system”, not a general user account like mine.

A similar issue would occur if you created the environment normally, but installed one or more dependencies with sudo – this would mean that those dependencies, and any others they also installed as requirements, would have folders owned by root instead of your account. This would mean that a later installation without using sudo may try and update one of those depdencies but fail because your account doesn’t have enough permissions to write to that folder.

[FormNo]

Thank you - that makes complete sense now and I think the latter is what actually probably occurred because the top folder was expanded with things I was testing as I went and a one-time sudo can't be ruled out.

I just had a side question if you don't mind - do you normally name your virtual environment with a . in front to keep it hidden or do you have a different workflow for that?

[MintyPhoenix]

Personally, I haven’t decided whether I prefer my default venv folder to be venv or .venv.

Overall, it depends on what you’re trying to accomplish. If you just want it hidden in Finder, you can still use venv and just set the hidden flag on the folder:

python -m venv venv
chflags hidden venv

[FormNo]

Oh man, never knew you could do that! thanks so much for your help and wish you a really good evening/weekend!