Warn about lack of uv venv support

crates/uv/src/commands/venv.rs

@@ -22,7 +22,7 @@ use uv_distribution_types::{
 use uv_fs::Simplified;
 use uv_install_wheel::LinkMode;
 use uv_normalize::DefaultGroups;
-use uv_preview::Preview;
+use uv_preview::{Preview, PreviewFeature};
 use uv_python::{
     EnvironmentPreference, PythonDownloads, PythonInstallation, PythonPreference, PythonRequest,
 };
@@ -34,7 +34,9 @@ use uv_types::{
 };
 use uv_virtualenv::OnExisting;
 use uv_warnings::warn_user;
-use uv_workspace::{DiscoveryOptions, VirtualProject, WorkspaceCache, WorkspaceErrorKind};
+use uv_workspace::{
+    DiscoveryOptions, ProjectEnvironmentTarget, VirtualProject, WorkspaceCache, WorkspaceErrorKind,
+};
 
 use crate::commands::ExitStatus;
 use crate::commands::pip::loggers::{DefaultInstallLogger, InstallLogger};
@@ -129,17 +131,22 @@ pub(crate) async fn venv(
         .as_ref()
         .map(VirtualProject::workspace)
         .filter(|workspace| path.is_none() && workspace.install_path() == project_dir);
+    let project_environment_target =
+        project_environment.map(|workspace| workspace.venv(Some(false)));
+
+    if project_environment_target
+        .as_ref()
+        .is_some_and(ProjectEnvironmentTarget::is_default)
+        && preview.is_enabled(PreviewFeature::CentralizedEnvs)
+    {
+        warn_user!("The `centralized-envs` preview feature currently has no effect on `uv venv`");
+    }
 
     // Determine the default path; either the virtual environment for the project or `.venv`.
     let path = path.unwrap_or_else(|| {
-        project_environment.map_or_else(
+        project_environment_target.map_or_else(
             || PathBuf::from(".venv"),
-            |workspace| {
-                workspace
-                    .venv(Some(false))
-                    .project_path(workspace.install_path())
-                    .into_owned()
-            },
+            |target| target.project_path(project_dir).into_owned(),
         )
     });
 

crates/uv/tests/python/venv.rs

@@ -74,6 +74,74 @@ fn create_venv() {
     context.venv.assert(predicates::path::is_dir());
 }
 
+#[test]
+fn create_venv_centralized_envs_warning() -> Result<()> {
+    let context = uv_test::test_context_with_versions!(&["3.12"]);
+
+    // The feature is project-scoped, so it does not warn outside a project.
+    uv_snapshot!(context.filters(), context.venv()
+        .arg("--preview-features")
+        .arg("centralized-envs")
+        .arg("--python")
+        .arg("3.12"), @"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+
+    ----- stderr -----
+    Using CPython 3.12.[X] interpreter at: [PYTHON-3.12]
+    Creating virtual environment at: .venv
+    Activate with: source .venv/[BIN]/activate
+    "
+    );
+
+    fs_err::remove_dir_all(&context.venv)?;
+    context
+        .temp_dir
+        .child("pyproject.toml")
+        .write_str(indoc! {r#"
+        [project]
+        name = "project"
+        version = "0.1.0"
+    "#})?;
+
+    uv_snapshot!(context.filters(), context.venv()
+        .arg("--preview-features")
+        .arg("centralized-envs")
+        .arg("--python")
+        .arg("3.12"), @"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+
+    ----- stderr -----
+    warning: The `centralized-envs` preview feature currently has no effect on `uv venv`
+    Using CPython 3.12.[X] interpreter at: [PYTHON-3.12]
+    Creating virtual environment at: .venv
+    Activate with: source .venv/[BIN]/activate
+    "
+    );
+
+    uv_snapshot!(context.filters(), context.venv()
+        .env(EnvVars::UV_PROJECT_ENVIRONMENT, "explicit")
+        .arg("--preview-features")
+        .arg("centralized-envs")
+        .arg("--python")
+        .arg("3.12"), @"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+
+    ----- stderr -----
+    Using CPython 3.12.[X] interpreter at: [PYTHON-3.12]
+    Creating virtual environment at: explicit
+    Activate with: source explicit/[BIN]/activate
+    "
+    );
+
+    Ok(())
+}
+
 #[test]
 fn create_venv_313() {
     let context = uv_test::test_context_with_versions!(&["3.13"]);