feat: use uv to create python's venv by default

docs/lang/python.md

@@ -101,6 +101,17 @@ Packages list to install with pip after installing a Python version.
 
 Automatically create a virtualenv in the directory specified by `_.python.venv` if it doesn't exist.
 
+Deprecated note: Use `env._python.venv` instead.
+
+### `python_venv_stdlib`
+
+* Type: `bool`
+* Env: `MISE_PYTHON_VENV_STDLIB`
+* Default: `false`
+
+Prefer to use venv from Python's standard library.
+By default, mise will prioritize `uv` for the virtual environment if `uv` is in the `PATH`.
+
 ## Default Python packages
 
 mise can automatically install a default set of Python packages with pip right after installing a

e2e/plugins/core/test_python_uv_venv

@@ -0,0 +1,39 @@
+#!/usr/bin/env bash
+
+export MISE_PYTHON_DEFAULT_PACKAGES_FILE="$HOME/.default-python-packages"
+
+cat >.mise.toml <<EOF
+[env._.python]
+venv = {path = "my_venv", create=true}
+[tools]
+python = "3.12.3"
+uv = "0.3.4"
+EOF
+
+mise i
+assert "mise x -- python --version" "Python 3.12.3"
+assert "mise x -- uv --version" "uv 0.3.4"
+assert "mise env -s bash | grep VIRTUAL_ENV" "export VIRTUAL_ENV=$PWD/my_venv"
+assert "mise x -- which python" "$PWD/my_venv/bin/python"
+assert "mise x -- uv pip list" "Package Version
+------- -------
+pip     24.0"
+
+# Allows opt-out uv's venv
+mkdir -p subdir
+cat >subdir/.mise.toml <<EOF
+[env._.python]
+venv = {path = "my_subvenv", create=true}
+[tools]
+python = "3.12.3"
+uv = "0.3.4"
+[settings]
+python_venv_stdlib = true
+EOF
+
+cd subdir || exit
+mise i
+assert "mise x -- python --version" "Python 3.12.3"
+assert "mise env -s bash | grep VIRTUAL_ENV" "export VIRTUAL_ENV=$PWD/my_subvenv"
+assert "mise x -- which python" "$PWD/my_subvenv/bin/python"
+assert_contains "ls $PWD/my_subvenv/" "include" # stdlib virtual venv has an "include" folder while uv doesn't

schema/mise.json

@@ -340,6 +340,10 @@
           "deprecated": "Use env._python.venv instead.",
           "type": "boolean"
         },
+        "python_venv_stdlib": {
+          "description": "Prefer to use venv from Python's standard library.",
+          "type": "boolean"
+        },
         "quiet": {
           "description": "Suppress all output except errors.",
           "type": "boolean"

settings.toml

@@ -374,6 +374,11 @@ hide = true
 deprecated = "Use env._python.venv instead."
 description = "Automatically create virtualenvs for python tools."
 
+[python_venv_stdlib]
+env = "MISE_VENV_STDLIB"
+type = "bool"
+description = "Use venv from Python's standard library."
+
 [quiet]
 env = "MISE_QUIET"
 type = "bool"

src/cli/settings/ls.rs

@@ -90,6 +90,7 @@ mod tests {
         plugin_autoupdate_last_check_duration = "20m"
         python_default_packages_file = "~/.default-python-packages"
         python_pyenv_repo = "https://github.com/pyenv/pyenv.git"
+        python_venv_stdlib = false
         quiet = false
         raw = false
         trusted_config_paths = []
@@ -149,6 +150,7 @@ mod tests {
         plugin_autoupdate_last_check_duration
         python_default_packages_file
         python_pyenv_repo
+        python_venv_stdlib
         quiet
         raw
         ruby

src/cli/settings/set.rs

@@ -178,6 +178,7 @@ pub mod tests {
         plugin_autoupdate_last_check_duration = "1"
         python_default_packages_file = "~/.default-python-packages"
         python_pyenv_repo = "https://github.com/pyenv/pyenv.git"
+        python_venv_stdlib = false
         quiet = false
         raw = false
         trusted_config_paths = []

src/cli/settings/unset.rs

@@ -81,6 +81,7 @@ mod tests {
         plugin_autoupdate_last_check_duration = "20m"
         python_default_packages_file = "~/.default-python-packages"
         python_pyenv_repo = "https://github.com/pyenv/pyenv.git"
+        python_venv_stdlib = false
         quiet = false
         raw = false
         trusted_config_paths = []

src/config/env_directive.rs

@@ -9,10 +9,11 @@ use serde::{Deserialize, Deserializer};
 
 use crate::cmd::CmdLineRunner;
 use crate::config::config_file::trust_check;
-use crate::config::{Config, Settings};
+use crate::config::settings::SETTINGS;
+use crate::config::Config;
 use crate::env::PATH_KEY;
 use crate::env_diff::{EnvDiff, EnvDiffOperation};
-use crate::file::display_path;
+use crate::file::{display_path, which_non_pristine};
 use crate::tera::{get_tera, BASE_CONTEXT};
 use crate::toolset::ToolsetBuilder;
 use crate::{dirs, env};
@@ -133,7 +134,6 @@ impl EnvResults {
         initial: &HashMap<String, String>,
         input: Vec<(EnvDirective, PathBuf)>,
     ) -> eyre::Result<Self> {
-        let settings = Settings::get();
         let mut ctx = BASE_CONTEXT.clone();
         trace!("resolve: input: {:#?}", &input);
         let mut env = initial
@@ -224,7 +224,7 @@ impl EnvResults {
                     }
                 }
                 EnvDirective::Source(input) => {
-                    settings.ensure_experimental("env._.source")?;
+                    SETTINGS.ensure_experimental("env._.source")?;
                     trust_check(&source)?;
                     let s = r.parse_template(&ctx, &source, input.to_string_lossy().as_ref())?;
                     for p in xx::file::glob(normalize_path(&config_root, s.into()))? {
@@ -258,20 +258,29 @@ impl EnvResults {
                             .into_iter()
                             .chain(env::split_paths(&env_vars[&*PATH_KEY]))
                             .collect::<Vec<_>>();
-                        let cmd = CmdLineRunner::new("python3")
-                            .args(["-m", "venv", &venv.to_string_lossy()])
-                            .envs(&env_vars)
-                            .env(
-                                PATH_KEY.to_string(),
-                                env::join_paths(&path)?.to_string_lossy().to_string(),
-                            );
                         if ts
                             .list_missing_versions()
                             .iter()
                             .any(|tv| tv.backend.name == "python")
                         {
                             debug!("python not installed, skipping venv creation");
                         } else {
+                            let cmd = if let (false, Some(_uv_in_path)) =
+                                (SETTINGS.python_venv_stdlib, which_non_pristine("uv"))
+                            {
+                                CmdLineRunner::new("uv").args(["venv", &venv.to_string_lossy()])
+                            } else {
+                                CmdLineRunner::new("python3").args([
+                                    "-m",
+                                    "venv",
+                                    &venv.to_string_lossy(),
+                                ])
+                            }
+                            .envs(&env_vars)
+                            .env(
+                                PATH_KEY.to_string(),
+                                env::join_paths(&path)?.to_string_lossy().to_string(),
+                            );
                             info!("creating venv at: {}", display_path(&venv));
                             cmd.execute()?;
                         }