Create temporary environments in dedicated cache bucket

crates/uv-build/Cargo.toml

@@ -18,10 +18,11 @@ distribution-types = { workspace = true }
 pep440_rs = { workspace = true }
 pep508_rs = { workspace = true }
 pypi-types = { workspace = true }
+uv-cache = { workspace = true }
+uv-configuration = { workspace = true }
 uv-fs = { workspace = true }
 uv-toolchain = { workspace = true }
 uv-types = { workspace = true }
-uv-configuration = { workspace = true }
 uv-virtualenv = { workspace = true }
 
 anyhow = { workspace = true }

crates/uv-build/src/lib.rs

@@ -29,6 +29,7 @@ use distribution_types::Resolution;
 use pep440_rs::Version;
 use pep508_rs::PackageName;
 use pypi_types::{Requirement, VerbatimParsedUrl};
+use uv_cache::CacheBucket;
 use uv_configuration::{BuildKind, ConfigSettings, SetupPyStrategy};
 use uv_fs::{PythonExt, Simplified};
 use uv_toolchain::{Interpreter, PythonEnvironment};
@@ -413,7 +414,7 @@ impl SourceBuild {
         mut environment_variables: FxHashMap<OsString, OsString>,
         concurrent_builds: usize,
     ) -> Result<Self, Error> {
-        let temp_dir = tempdir_in(build_context.cache().root())?;
+        let temp_dir = tempdir_in(build_context.cache().bucket(CacheBucket::Environments))?;
 
         let source_tree = if let Some(subdir) = subdirectory {
             source.join(subdir)
@@ -431,7 +432,7 @@ impl SourceBuild {
         // Create a virtual environment, or install into the shared environment if requested.
         let venv = match build_isolation {
             BuildIsolation::Isolated => uv_virtualenv::create_venv(
-                &temp_dir.path().join(".venv"),
+                temp_dir.path(),
                 interpreter.clone(),
                 uv_virtualenv::Prompt::None,
                 false,

crates/uv-cache/src/lib.rs

@@ -628,6 +628,8 @@ pub enum CacheBucket {
     /// that cache entries can be atomically replaced and removed, as storing directories in the
     /// other buckets directly would make atomic operations impossible.
     Archive,
+    /// Ephemeral virtual environments used to execute PEP 517 builds and other operations.
+    Environments,
 }
 
 impl CacheBucket {
@@ -640,6 +642,7 @@ impl CacheBucket {
             Self::Simple => "simple-v8",
             Self::Wheels => "wheels-v1",
             Self::Archive => "archive-v0",
+            Self::Environments => "environments-v0",
         }
     }
 
@@ -750,20 +753,24 @@ impl CacheBucket {
             Self::Archive => {
                 // Nothing to do.
             }
+            Self::Environments => {
+                // Nothing to do.
+            }
         }
         Ok(summary)
     }
 
     /// Return an iterator over all cache buckets.
-    pub fn iter() -> impl Iterator<Item = CacheBucket> {
+    pub fn iter() -> impl Iterator<Item = Self> {
         [
-            CacheBucket::Wheels,
-            CacheBucket::BuiltWheels,
-            CacheBucket::FlatIndex,
-            CacheBucket::Git,
-            CacheBucket::Interpreter,
-            CacheBucket::Simple,
-            CacheBucket::Archive,
+            Self::Wheels,
+            Self::BuiltWheels,
+            Self::FlatIndex,
+            Self::Git,
+            Self::Interpreter,
+            Self::Simple,
+            Self::Archive,
+            Self::Environments,
         ]
         .iter()
         .copied()

crates/uv/src/commands/project/run.rs

@@ -8,7 +8,7 @@ use tempfile::tempdir_in;
 use tokio::process::Command;
 use tracing::debug;
 
-use uv_cache::Cache;
+use uv_cache::{Cache, CacheBucket};
 use uv_client::{BaseClientBuilder, Connectivity};
 use uv_configuration::{ExtrasSpecification, PreviewMode, Upgrade};
 use uv_distribution::{ProjectWorkspace, Workspace};
@@ -107,7 +107,7 @@ pub(crate) async fn run(
     };
 
     // If necessary, create an environment for the ephemeral requirements.
-    let tmpdir;
+    let temp_dir;
     let ephemeral_env = if requirements.is_empty() {
         None
     } else {
@@ -135,12 +135,9 @@ pub(crate) async fn run(
         // environment.
 
         // Create a virtual environment
-        // TODO(zanieb): Move this path derivation elsewhere
-        let uv_state_path = std::env::current_dir()?.join(".uv");
-        fs_err::create_dir_all(&uv_state_path)?;
-        tmpdir = tempdir_in(uv_state_path)?;
+        temp_dir = tempdir_in(cache.bucket(CacheBucket::Environments))?;
         let venv = uv_virtualenv::create_venv(
-            tmpdir.path(),
+            temp_dir.path(),
             interpreter,
             uv_virtualenv::Prompt::None,
             false,

crates/uv/src/commands/tool/run.rs

@@ -8,7 +8,7 @@ use tempfile::tempdir_in;
 use tokio::process::Command;
 use tracing::debug;
 
-use uv_cache::Cache;
+use uv_cache::{Cache, CacheBucket};
 use uv_client::Connectivity;
 use uv_configuration::PreviewMode;
 use uv_requirements::RequirementsSource;
@@ -61,13 +61,10 @@ pub(crate) async fn run(
     )?
     .into_interpreter();
 
-    // Create a virtual environment1
-    // TODO(zanieb): Move this path derivation elsewhere
-    let uv_state_path = std::env::current_dir()?.join(".uv");
-    fs_err::create_dir_all(&uv_state_path)?;
-    let tmpdir = tempdir_in(uv_state_path)?;
+    // Create a virtual environment.
+    let temp_dir = tempdir_in(cache.bucket(CacheBucket::Environments))?;
     let venv = uv_virtualenv::create_venv(
-        tmpdir.path(),
+        temp_dir.path(),
         interpreter,
         uv_virtualenv::Prompt::None,
         false,