You do not need a damn good reason for this. Just try it out on a simple hello world. Then try it out on a project already using poetry for eg.

uv init

uv sync

and you're done

I'd say if you do not run into the pitfalls of a large python codebase with hundreds of dependencies, you'll not get the bigger argument people are talking about.

I don't think you need to sync, do you? It always just does it when running.

That said, I do wish uv had `uv activate`. I like just working in the virtualenv without having to `uv run` everything.

I do usually include instructions in our READMEs to do a `uv sync` as install command, in order to separate error causes, and also to allow for bootstrapping the venv so that it's available for IDEs.

That makes sense, thanks.

You can still `source .venv/bin/activate(.fish)` and skip the uv run bit. I have Fish shell configured to automatically activate a .venv if it finds one in a directory I switch to.

I do do that, can you please share your fish script to autoload it? I have something for Poetry envs, but not venv dirs.

Sure thing - so I mostly ended up using this for activating a .venv in a fabfile directory using this...

    function __auto_fab --on-variable PWD
        iterm2_print_user_vars
        if [ -d "fabfile" ]
            if [ -d "fabfile/.venv" ]
                if not set -q done_fab
                    and not set -q VIRTUAL_ENV
                    echo -n "Starting fabfile venv... "
                    pushd fabfile > /dev/null
                    source .venv/bin/activate.fish  --prompt="[fab]"
                    popd > /dev/null
                    set -g done_fab 1
                    echo -e "\r Fabfile venv activated         "
                end
            else
                echo "Run gofab to create the .venv"
            end
        end
    end

I've since deleted the one to do a .venv in this directory, but I think it was roughly this...

    function __auto_venv --on-variable PWD
        if [ -d ".venv" ]
            if not set -q done_venv
                echo -n "Starting venv... "
                source .venv/bin/activate.fish  --prompt="[venv]"
                set -g done_venv 1
                echo -e "\r Venv activated         "
            end
        end
    end

(just tested that and it seems to work - the --prompt actually gets overridden by the project name from uv's pyproject.toml now though so that's not really necessary, was useful at some point in the past)

These live in ~/.config/fish/conf.d/events.fish

Thank you!

I'm not them, but I use `direnv` for this. Their wiki includes two layout_uv[1] scripts, one that uses `uv` just to activate a regular venv and a second that uses it to manage the whole project. I use the latter.

[1] https://github.com/direnv/direnv/wiki/Python

That's great, thanks! I use direnv but didn't know they had this.

Custom layouts are awesome. You can set up any script to run when direnv runs, so you can support just about anything you want even before direnv adds a builtin.

I keep going back and forth on ‘uv run’. I like being explicit with the tooling, but it feels like extra unneeded verbosity when you could just interact with the venv directly. Especially since I ported a bunch of scripts from ‘poetry run’

> I am a casual user of python and I don't want to touch it unless I have a damn good reason to use it.

I... what? Python is a beautiful way to evolve beyond the troglodyte world of sh for system scripts. You are seriously missing out by being so pertinently against it.

Just you wait till someone shows you how Rust is to Python what Python is to shell scripts. For one, null safety is a major issue in most corporate Python code, and much less of an issue in Rust code.

Rust is decidedly not a scripting language.

Don't get me wrong, Rust is great and I use it too, but for very different purposes than (system) scripts.