Creating a venv with uv does not use the correct python version

[FlorianGD]

Hello,

First, thanks for the great tool, I have been using it and advising people to use it for quite some time, it is really valuable ! I regularly update the tool via cargo install-update, and it seems I have been bitten by using the latest version.

Describe the bug When setting a new python project, I want mise to create and activate the virtual env for me, using the version given in .mise.toml. It used to work fine. The latest version seems to use uv to create the virtual env, resulting in the wrong python version being installed.

To Reproduce With the setting python.venv_stdlib as false, and with the following .mise.toml

[env]
_.file = ".env"
_.python.venv = { path = ".venv", create = true }

[tools]
python = { version = "3.10" }

When I enter the directory with no .venv created, this is what I see:

mise creating venv with uv at: ~/REDACTED/.venv
Using CPython 3.11.10
Creating virtual environment at: .venv
Activate with: source .venv/bin/activate.fish

Notice the using CPython 3.11.10 when I want python 3.10 as per the .mise.toml file.

Moreover, I do not have the pip binary in the virtualenv. Manually activating the env does not change it.

$ python -V
Python 3.11.10
$ which pip
/HOME/.local/share/mise/installs/python/3.10.13/bin/pip
$ source .venv/bin/activate.fish
$ which pip
/HOME/.local/share/mise/installs/python/3.10.13/bin/pip

If I change the setting python.venv_stdlib as true, then I have the correct behavior (though, the creation is slower because it does not use uv anymore)

$ mise settings set python.venv_stdlib true
$ rm -rf .venv
mise creating venv with stdlib at: REDACTED/.venv
$ which python
REDACTED/.venv/bin/python
$ python -V
Python 3.10.13
$ which pip
REDACTED/.venv/bin/pip

Expected behavior I'd like to create the virtualenv with uv and having the correct python version installed in the virtual environment.

I have uv installed externally of the project, using pipx and python version 3.12 if that matters. Setting python.uv_venv_auto does not seem to change as this project does not use uv.lock.

mise doctor output

version: 2024.11.37 linux-x64 (7ac5ab3 2024-11-30)
activated: yes
shims_on_path: no

build_info:
  Target: x86_64-unknown-linux-gnu
  Features: DEFAULT, NATIVE_TLS, OPENSSL
  Built: Sat, 30 Nov 2024 01:03:00 +0000
  Rust Version: rustc 1.82.0 (f6e511eec 2024-10-15)
  Profile: release

shell:
  /usr/bin/fish
  fish, version 3.7.1

dirs:
  cache: ~/.cache/mise
  config: ~/.config/mise
  data: ~/.local/share/mise
  shims: ~/.local/share/mise/shims
  state: ~/.local/state/mise

config_files:
  ~/.config/mise/config.toml
  ~/REDACTED/.mise.toml

backends:
  aqua
  asdf
  cargo
  core
  gem
  go
  npm
  pipx
  spm
  ubi
  vfox

plugins:
  chezmoi  https://github.com/joke/asdf-chezmoi.git#53f30be
  go       https://github.com/kennyp/asdf-golang.git#d4f1d65
  haskell  https://github.com/asdf-community/asdf-haskell.git#499d84c
  java     https://github.com/rtx-plugins/rtx-java.git#6c6790c
  jq       https://github.com/azmcode/asdf-jq.git#a13dea7
  meson    https://github.com/asdf-community/asdf-meson.git#212ecdb
  ninja    https://github.com/asdf-community/asdf-ninja.git#e196e02
  yarn     https://github.com/twuni/asdf-yarn.git#376c540

toolset:
  core:[email protected]

env_vars:
  MISE_SHELL=fish

settings:
  experimental         true  ~/.config/mise/config.toml
  python.uv_venv_auto  true  ~/.config/mise/config.toml
  python.venv_stdlib   false ~/.config/mise/config.toml

2 warnings found:

1. plugin go overrides a core plugin

2. plugin java overrides a core plugin

No problems found

Additional context I use ubuntu 20.04.