Respect .python-version files and pyproject.toml in uv python find

crates/uv-cli/src/lib.rs

@@ -3031,6 +3031,13 @@ pub struct PythonFindArgs {
  ///
  /// See `uv help python` to view supported request formats.
  pub request: Option<String>,
+
+ /// Avoid discovering a project or workspace.
+ ///
+ /// Otherwise, when no request is provided, the Python requirement of a project in the current
+ /// directory or parent directories will be used.
+ #[arg(long, alias = "no_workspace")]
+ pub no_project: bool,
 }
 
 #[derive(Args)]

crates/uv/src/commands/python/find.rs

@@ -2,23 +2,60 @@ use anstream::println;
 use anyhow::Result;
 
 use uv_cache::Cache;
-use uv_fs::Simplified;
-use uv_python::{EnvironmentPreference, PythonInstallation, PythonPreference, PythonRequest};
+use uv_fs::{Simplified, CWD};
+use uv_python::{
+ EnvironmentPreference, PythonInstallation, PythonPreference, PythonRequest, PythonVersionFile,
+ VersionRequest,
+};
+use uv_resolver::RequiresPython;
+use uv_warnings::warn_user_once;
+use uv_workspace::{DiscoveryOptions, VirtualProject, WorkspaceError};
 
-use crate::commands::ExitStatus;
+use crate::commands::{project::find_requires_python, ExitStatus};
 
 /// Find a Python interpreter.
 pub(crate) async fn find(
  request: Option<String>,
+ no_project: bool,
+ no_config: bool,
  python_preference: PythonPreference,
  cache: &Cache,
 ) -> Result<ExitStatus> {
- let request = match request {
- Some(request) => PythonRequest::parse(&request),
- None => PythonRequest::Any,
- };
+ // (1) Explicit request from user
+ let mut request = request.map(|request| PythonRequest::parse(&request));
+
+ // (2) Request from `.python-version`
+ if request.is_none() {
+ request = PythonVersionFile::discover(&*CWD, no_config)
+ .await?
+ .and_then(PythonVersionFile::into_version);
+ }
+
+ // (3) `Requires-Python` in `pyproject.toml`
+ if request.is_none() && !no_project {
+ let project = match VirtualProject::discover(&CWD, &DiscoveryOptions::default()).await {
+ Ok(project) => Some(project),
+ Err(WorkspaceError::MissingProject(_)) => None,
+ Err(WorkspaceError::MissingPyprojectToml) => None,
+ Err(WorkspaceError::NonWorkspace(_)) => None,
+ Err(err) => {
+ warn_user_once!("{err}");
+ None
+ }
+ };
+
+ if let Some(project) = project {
+ request = find_requires_python(project.workspace())?
+ .as_ref()
+ .map(RequiresPython::specifiers)
+ .map(|specifiers| {
+ PythonRequest::Version(VersionRequest::Range(specifiers.clone()))
+ });
+ }
+ }
+
  let python = PythonInstallation::find(
- &request,
+ &request.unwrap_or_default(),
  EnvironmentPreference::OnlySystem,
  python_preference,
  cache,

crates/uv/src/lib.rs

@@ -916,7 +916,14 @@ async fn run(cli: Cli) -> Result<ExitStatus> {
  // Initialize the cache.
  let cache = cache.init()?;
 
- commands::python_find(args.request, globals.python_preference, &cache).await
+ commands::python_find(
+ args.request,
+ args.no_project,
+ cli.no_config,
+ globals.python_preference,
+ &cache,
+ )
+ .await
  }
  Commands::Python(PythonNamespace {
  command: PythonCommand::Pin(args),

crates/uv/src/settings.rs

@@ -564,15 +564,22 @@ impl PythonUninstallSettings {
 #[derive(Debug, Clone)]
 pub(crate) struct PythonFindSettings {
  pub(crate) request: Option<String>,
+ pub(crate) no_project: bool,
 }
 
 impl PythonFindSettings {
  /// Resolve the [`PythonFindSettings`] from the CLI and workspace configuration.
  #[allow(clippy::needless_pass_by_value)]
  pub(crate) fn resolve(args: PythonFindArgs, _filesystem: Option<FilesystemOptions>) -> Self {
- let PythonFindArgs { request } = args;
+ let PythonFindArgs {
+ request,
+ no_project,
+ } = args;
 
- Self { request }
+ Self {
+ request,
+ no_project,
+ }
  }
 }
 

crates/uv/tests/python_find.rs

@@ -1,5 +1,9 @@
 #![cfg(all(feature = "python", feature = "pypi"))]
 
+use assert_fs::fixture::FileWriteStr;
+use assert_fs::prelude::PathChild;
+use indoc::indoc;
+
 use common::{uv_snapshot, TestContext};
 use uv_python::platform::{Arch, Os};
 
@@ -148,3 +152,94 @@ fn python_find() {
  ----- stderr -----
  "###);
 }
+
+#[test]
+fn python_find_pin() {
+ let context: TestContext = TestContext::new_with_versions(&["3.11", "3.12"]);
+
+ // Pin to a version
+ uv_snapshot!(context.filters(), context.python_pin().arg("3.12"), @r###"
+ success: true
+ exit_code: 0
+ ----- stdout -----
+ Pinned `.python-version` to `3.12`
+
+ ----- stderr -----
+ "###);
+
+ // We should find the pinned version, not the first on the path
+ uv_snapshot!(context.filters(), context.python_find(), @r###"
+ success: true
+ exit_code: 0
+ ----- stdout -----
+ [PYTHON-3.12]
+
+ ----- stderr -----
+ "###);
+
+ // Unless explicitly requested
+ uv_snapshot!(context.filters(), context.python_find().arg("3.11"), @r###"
+ success: true
+ exit_code: 0
+ ----- stdout -----
+ [PYTHON-3.11]
+
+ ----- stderr -----
+ "###);
+
+ // Or `--no-config` is used
+ uv_snapshot!(context.filters(), context.python_find().arg("--no-config"), @r###"
+ success: true
+ exit_code: 0
+ ----- stdout -----
+ [PYTHON-3.11]
+
+ ----- stderr -----
+ "###);
+}
+
+#[test]
+fn python_find_project() {
+ let context: TestContext = TestContext::new_with_versions(&["3.11", "3.12"]);
+
+ let pyproject_toml = context.temp_dir.child("pyproject.toml");
+ pyproject_toml
+ .write_str(indoc! {r#"
+ [project]
+ name = "project"
+ version = "0.1.0"
+ requires-python = ">=3.12"
+ dependencies = ["anyio==3.7.0"]
+ "#})
+ .unwrap();
+
+ // We should respect the project's required version, not the first on the path
+ uv_snapshot!(context.filters(), context.python_find(), @r###"
+ success: true
+ exit_code: 0
+ ----- stdout -----
+ [PYTHON-3.12]
+
+ ----- stderr -----
+ "###);
+
+ // Unless explicitly requested
+ uv_snapshot!(context.filters(), context.python_find().arg("3.11"), @r###"
+ success: true
+ exit_code: 0
+ ----- stdout -----
+ [PYTHON-3.11]
+
+ ----- stderr -----
+ "###);
+
+ // Or `--no-project` is used
+ uv_snapshot!(context.filters(), context.python_find().arg("--no-project"), @r###"
+ success: true
+ exit_code: 0
+ ----- stdout -----
+ [PYTHON-3.11]
+
+ ----- stderr -----
+ "###);
+}