Files
uv/crates/uv-python/src/interpreter.rs
T
Zanie Blue 1c7c174bc8 Include the canonical path in the interpreter query cache key (#14331)
This fixes an obscure cache collision in Python interpreter queries,
which we believe to be the root cause of CI flakes we've been seeing
where a project environment is invalidated and recreated.

This work follows from the logs in [this CI
run](https://github.com/astral-sh/uv/actions/runs/15934322410/job/44950599993?pr=14326)
which captured one of the flakes with tracing enabled. There, we can see
that the project environment is invalidated because the Python
interpreter in the environment has a different version than expected:

```
DEBUG Checking for Python environment at `.venv`
TRACE Cached interpreter info for Python 3.12.9, skipping probing: .venv/bin/python3
DEBUG The interpreter in the project environment has different version (3.12.9) than it was created with (3.9.21)
```

(this message is updated to reflect #14329)

The flow is roughly:

- We create an environment with 3.12.9
- We query the environment, and cache the interpreter version for
`.venv/bin/python`
- We create an environment for 3.9.12, replacing the existing one
- We query the environment, and read the cached information

The Python cache entries are keyed by the absolute path to the
interpreter, and rely on the modification time (ctime, nsec resolution)
of the canonicalized path to determine if the cache entry should be
invalidated. The key is a hex representation of a u64 sea hasher output
— which is very unlikely to collide.

After an audit of the Python query caching logic, we determined that the
most likely cause of a collision in cache entries is that the
modification times of underlying interpreters are identical. This seems
pretty feasible, especially if the file system does not support
nanosecond precision — though it appears that the GitHub runners do
support it.

The fix here is to include the canonicalized path in the cache key,
which ensures we're looking at the modification time of the _same_
underlying interpreter.

This will "invalidate" all existing interpreter cache entries but that's
not a big deal.

This should also have the effect of reducing cache churn for
interpreters in virtual environments. Now, when you change Python
versions, we won't invalidate the previous cache entry so if you change
_back_ to the old version we can re-use our cached information.

It's a bit speculative, since we don't have a deterministic reproduction
in CI, but this is the strongest candidate given the logs and should
increase correctness regardless.

Closes https://github.com/astral-sh/uv/issues/14160
Closes https://github.com/astral-sh/uv/issues/13744
Closes https://github.com/astral-sh/uv/issues/13745

Once it's confirmed the flakes are resolved, we should revert

- https://github.com/astral-sh/uv/pull/14275
- #13817
2025-06-30 15:39:47 +00:00

1270 lines
47 KiB
Rust

use std::borrow::Cow;
use std::env::consts::ARCH;
use std::fmt::{Display, Formatter};
use std::path::{Path, PathBuf};
use std::process::{Command, ExitStatus};
use std::sync::OnceLock;
use std::{env, io};
use configparser::ini::Ini;
use fs_err as fs;
use owo_colors::OwoColorize;
use same_file::is_same_file;
use serde::{Deserialize, Serialize};
use thiserror::Error;
use tracing::{debug, trace, warn};
use uv_cache::{Cache, CacheBucket, CachedByTimestamp, Freshness};
use uv_cache_info::Timestamp;
use uv_cache_key::cache_digest;
use uv_fs::{LockedFile, PythonExt, Simplified, write_atomic_sync};
use uv_install_wheel::Layout;
use uv_pep440::Version;
use uv_pep508::{MarkerEnvironment, StringVersion};
use uv_platform_tags::Platform;
use uv_platform_tags::{Tags, TagsError};
use uv_pypi_types::{ResolverMarkerEnvironment, Scheme};
use crate::implementation::LenientImplementationName;
use crate::managed::ManagedPythonInstallations;
use crate::platform::{Arch, Libc, Os};
use crate::pointer_size::PointerSize;
use crate::{
Prefix, PythonInstallationKey, PythonVariant, PythonVersion, Target, VersionRequest,
VirtualEnvironment,
};
/// A Python executable and its associated platform markers.
#[derive(Debug, Clone)]
pub struct Interpreter {
platform: Platform,
markers: Box<MarkerEnvironment>,
scheme: Scheme,
virtualenv: Scheme,
manylinux_compatible: bool,
sys_prefix: PathBuf,
sys_base_exec_prefix: PathBuf,
sys_base_prefix: PathBuf,
sys_base_executable: Option<PathBuf>,
sys_executable: PathBuf,
sys_path: Vec<PathBuf>,
stdlib: PathBuf,
standalone: bool,
tags: OnceLock<Tags>,
target: Option<Target>,
prefix: Option<Prefix>,
pointer_size: PointerSize,
gil_disabled: bool,
real_executable: PathBuf,
}
impl Interpreter {
/// Detect the interpreter info for the given Python executable.
pub fn query(executable: impl AsRef<Path>, cache: &Cache) -> Result<Self, Error> {
let info = InterpreterInfo::query_cached(executable.as_ref(), cache)?;
debug_assert!(
info.sys_executable.is_absolute(),
"`sys.executable` is not an absolute Python; Python installation is broken: {}",
info.sys_executable.display()
);
Ok(Self {
platform: info.platform,
markers: Box::new(info.markers),
scheme: info.scheme,
virtualenv: info.virtualenv,
manylinux_compatible: info.manylinux_compatible,
sys_prefix: info.sys_prefix,
sys_base_exec_prefix: info.sys_base_exec_prefix,
pointer_size: info.pointer_size,
gil_disabled: info.gil_disabled,
sys_base_prefix: info.sys_base_prefix,
sys_base_executable: info.sys_base_executable,
sys_executable: info.sys_executable,
sys_path: info.sys_path,
stdlib: info.stdlib,
standalone: info.standalone,
tags: OnceLock::new(),
target: None,
prefix: None,
real_executable: executable.as_ref().to_path_buf(),
})
}
/// Return a new [`Interpreter`] with the given virtual environment root.
#[must_use]
pub fn with_virtualenv(self, virtualenv: VirtualEnvironment) -> Self {
Self {
scheme: virtualenv.scheme,
sys_base_executable: Some(virtualenv.base_executable),
sys_executable: virtualenv.executable,
sys_prefix: virtualenv.root,
target: None,
prefix: None,
..self
}
}
/// Return a new [`Interpreter`] to install into the given `--target` directory.
pub fn with_target(self, target: Target) -> io::Result<Self> {
target.init()?;
Ok(Self {
target: Some(target),
..self
})
}
/// Return a new [`Interpreter`] to install into the given `--prefix` directory.
pub fn with_prefix(self, prefix: Prefix) -> io::Result<Self> {
prefix.init(self.virtualenv())?;
Ok(Self {
prefix: Some(prefix),
..self
})
}
/// Return the base Python executable; that is, the Python executable that should be
/// considered the "base" for the virtual environment. This is typically the Python executable
/// from the [`Interpreter`]; however, if the interpreter is a virtual environment itself, then
/// the base Python executable is the Python executable of the interpreter's base interpreter.
///
/// This routine relies on `sys._base_executable`, falling back to `sys.executable` if unset.
/// Broadly, this routine should be used when attempting to determine the "base Python
/// executable" in a way that is consistent with the CPython standard library, such as when
/// determining the `home` key for a virtual environment.
pub fn to_base_python(&self) -> Result<PathBuf, io::Error> {
let base_executable = self.sys_base_executable().unwrap_or(self.sys_executable());
let base_python = std::path::absolute(base_executable)?;
Ok(base_python)
}
/// Determine the base Python executable; that is, the Python executable that should be
/// considered the "base" for the virtual environment. This is typically the Python executable
/// from the [`Interpreter`]; however, if the interpreter is a virtual environment itself, then
/// the base Python executable is the Python executable of the interpreter's base interpreter.
///
/// This routine mimics the CPython `getpath.py` logic in order to make a more robust assessment
/// of the appropriate base Python executable. Broadly, this routine should be used when
/// attempting to determine the "true" base executable for a Python interpreter by resolving
/// symlinks until a valid Python installation is found. In particular, we tend to use this
/// routine for our own managed (or standalone) Python installations.
pub fn find_base_python(&self) -> Result<PathBuf, io::Error> {
let base_executable = self.sys_base_executable().unwrap_or(self.sys_executable());
// In `python-build-standalone`, a symlinked interpreter will return its own executable path
// as `sys._base_executable`. Using the symlinked path as the base Python executable can be
// incorrect, since it could cause `home` to point to something that is _not_ a Python
// installation. Specifically, if the interpreter _itself_ is symlinked to an arbitrary
// location, we need to fully resolve it to the actual Python executable; however, if the
// entire standalone interpreter is symlinked, then we can use the symlinked path.
//
// We emulate CPython's `getpath.py` to ensure that the base executable results in a valid
// Python prefix when converted into the `home` key for `pyvenv.cfg`.
let base_python = match find_base_python(
base_executable,
self.python_major(),
self.python_minor(),
self.variant().suffix(),
) {
Ok(path) => path,
Err(err) => {
warn!("Failed to find base Python executable: {err}");
canonicalize_executable(base_executable)?
}
};
Ok(base_python)
}
/// Returns the path to the Python virtual environment.
#[inline]
pub fn platform(&self) -> &Platform {
&self.platform
}
/// Returns the [`MarkerEnvironment`] for this Python executable.
#[inline]
pub const fn markers(&self) -> &MarkerEnvironment {
&self.markers
}
/// Return the [`ResolverMarkerEnvironment`] for this Python executable.
pub fn resolver_marker_environment(&self) -> ResolverMarkerEnvironment {
ResolverMarkerEnvironment::from(self.markers().clone())
}
/// Returns the [`PythonInstallationKey`] for this interpreter.
pub fn key(&self) -> PythonInstallationKey {
PythonInstallationKey::new(
LenientImplementationName::from(self.implementation_name()),
self.python_major(),
self.python_minor(),
self.python_patch(),
self.python_version().pre(),
self.os(),
self.arch(),
self.libc(),
self.variant(),
)
}
pub fn variant(&self) -> PythonVariant {
if self.gil_disabled() {
PythonVariant::Freethreaded
} else {
PythonVariant::default()
}
}
/// Return the [`Arch`] reported by the interpreter platform tags.
pub fn arch(&self) -> Arch {
Arch::from(&self.platform().arch())
}
/// Return the [`Libc`] reported by the interpreter platform tags.
pub fn libc(&self) -> Libc {
Libc::from(self.platform().os())
}
/// Return the [`Os`] reported by the interpreter platform tags.
pub fn os(&self) -> Os {
Os::from(self.platform().os())
}
/// Returns the [`Tags`] for this Python executable.
pub fn tags(&self) -> Result<&Tags, TagsError> {
if self.tags.get().is_none() {
let tags = Tags::from_env(
self.platform(),
self.python_tuple(),
self.implementation_name(),
self.implementation_tuple(),
self.manylinux_compatible,
self.gil_disabled,
)?;
self.tags.set(tags).expect("tags should not be set");
}
Ok(self.tags.get().expect("tags should be set"))
}
/// Returns `true` if the environment is a PEP 405-compliant virtual environment.
///
/// See: <https://github.com/pypa/pip/blob/0ad4c94be74cc24874c6feb5bb3c2152c398a18e/src/pip/_internal/utils/virtualenv.py#L14>
pub fn is_virtualenv(&self) -> bool {
// Maybe this should return `false` if it's a target?
self.sys_prefix != self.sys_base_prefix
}
/// Returns `true` if the environment is a `--target` environment.
pub fn is_target(&self) -> bool {
self.target.is_some()
}
/// Returns `true` if the environment is a `--prefix` environment.
pub fn is_prefix(&self) -> bool {
self.prefix.is_some()
}
/// Returns `true` if this interpreter is managed by uv.
///
/// Returns `false` if we cannot determine the path of the uv managed Python interpreters.
pub fn is_managed(&self) -> bool {
let Ok(installations) = ManagedPythonInstallations::from_settings(None) else {
return false;
};
installations
.find_all()
.into_iter()
.flatten()
.any(|install| install.path() == self.sys_base_prefix)
}
/// Returns `Some` if the environment is externally managed, optionally including an error
/// message from the `EXTERNALLY-MANAGED` file.
///
/// See: <https://packaging.python.org/en/latest/specifications/externally-managed-environments/>
pub fn is_externally_managed(&self) -> Option<ExternallyManaged> {
// Per the spec, a virtual environment is never externally managed.
if self.is_virtualenv() {
return None;
}
// If we're installing into a target or prefix directory, it's never externally managed.
if self.is_target() || self.is_prefix() {
return None;
}
let Ok(contents) = fs::read_to_string(self.stdlib.join("EXTERNALLY-MANAGED")) else {
return None;
};
let mut ini = Ini::new_cs();
ini.set_multiline(true);
let Ok(mut sections) = ini.read(contents) else {
// If a file exists but is not a valid INI file, we assume the environment is
// externally managed.
return Some(ExternallyManaged::default());
};
let Some(section) = sections.get_mut("externally-managed") else {
// If the file exists but does not contain an "externally-managed" section, we assume
// the environment is externally managed.
return Some(ExternallyManaged::default());
};
let Some(error) = section.remove("Error") else {
// If the file exists but does not contain an "Error" key, we assume the environment is
// externally managed.
return Some(ExternallyManaged::default());
};
Some(ExternallyManaged { error })
}
/// Returns the `python_full_version` marker corresponding to this Python version.
#[inline]
pub fn python_full_version(&self) -> &StringVersion {
self.markers.python_full_version()
}
/// Returns the full Python version.
#[inline]
pub fn python_version(&self) -> &Version {
&self.markers.python_full_version().version
}
/// Returns the Python version up to the minor component.
#[inline]
pub fn python_minor_version(&self) -> Version {
Version::new(self.python_version().release().iter().take(2).copied())
}
/// Returns the Python version up to the patch component.
#[inline]
pub fn python_patch_version(&self) -> Version {
Version::new(self.python_version().release().iter().take(3).copied())
}
/// Return the major version component of this Python version.
pub fn python_major(&self) -> u8 {
let major = self.markers.python_full_version().version.release()[0];
u8::try_from(major).expect("invalid major version")
}
/// Return the minor version component of this Python version.
pub fn python_minor(&self) -> u8 {
let minor = self.markers.python_full_version().version.release()[1];
u8::try_from(minor).expect("invalid minor version")
}
/// Return the patch version component of this Python version.
pub fn python_patch(&self) -> u8 {
let minor = self.markers.python_full_version().version.release()[2];
u8::try_from(minor).expect("invalid patch version")
}
/// Returns the Python version as a simple tuple, e.g., `(3, 12)`.
pub fn python_tuple(&self) -> (u8, u8) {
(self.python_major(), self.python_minor())
}
/// Return the major version of the implementation (e.g., `CPython` or `PyPy`).
pub fn implementation_major(&self) -> u8 {
let major = self.markers.implementation_version().version.release()[0];
u8::try_from(major).expect("invalid major version")
}
/// Return the minor version of the implementation (e.g., `CPython` or `PyPy`).
pub fn implementation_minor(&self) -> u8 {
let minor = self.markers.implementation_version().version.release()[1];
u8::try_from(minor).expect("invalid minor version")
}
/// Returns the implementation version as a simple tuple.
pub fn implementation_tuple(&self) -> (u8, u8) {
(self.implementation_major(), self.implementation_minor())
}
/// Returns the implementation name (e.g., `CPython` or `PyPy`).
pub fn implementation_name(&self) -> &str {
self.markers.implementation_name()
}
/// Return the `sys.base_exec_prefix` path for this Python interpreter.
pub fn sys_base_exec_prefix(&self) -> &Path {
&self.sys_base_exec_prefix
}
/// Return the `sys.base_prefix` path for this Python interpreter.
pub fn sys_base_prefix(&self) -> &Path {
&self.sys_base_prefix
}
/// Return the `sys.prefix` path for this Python interpreter.
pub fn sys_prefix(&self) -> &Path {
&self.sys_prefix
}
/// Return the `sys._base_executable` path for this Python interpreter. Some platforms do not
/// have this attribute, so it may be `None`.
pub fn sys_base_executable(&self) -> Option<&Path> {
self.sys_base_executable.as_deref()
}
/// Return the `sys.executable` path for this Python interpreter.
pub fn sys_executable(&self) -> &Path {
&self.sys_executable
}
/// Return the "real" queried executable path for this Python interpreter.
pub fn real_executable(&self) -> &Path {
&self.real_executable
}
/// Return the `sys.path` for this Python interpreter.
pub fn sys_path(&self) -> &Vec<PathBuf> {
&self.sys_path
}
/// Return the `stdlib` path for this Python interpreter, as returned by `sysconfig.get_paths()`.
pub fn stdlib(&self) -> &Path {
&self.stdlib
}
/// Return the `purelib` path for this Python interpreter, as returned by `sysconfig.get_paths()`.
pub fn purelib(&self) -> &Path {
&self.scheme.purelib
}
/// Return the `platlib` path for this Python interpreter, as returned by `sysconfig.get_paths()`.
pub fn platlib(&self) -> &Path {
&self.scheme.platlib
}
/// Return the `scripts` path for this Python interpreter, as returned by `sysconfig.get_paths()`.
pub fn scripts(&self) -> &Path {
&self.scheme.scripts
}
/// Return the `data` path for this Python interpreter, as returned by `sysconfig.get_paths()`.
pub fn data(&self) -> &Path {
&self.scheme.data
}
/// Return the `include` path for this Python interpreter, as returned by `sysconfig.get_paths()`.
pub fn include(&self) -> &Path {
&self.scheme.include
}
/// Return the [`Scheme`] for a virtual environment created by this [`Interpreter`].
pub fn virtualenv(&self) -> &Scheme {
&self.virtualenv
}
/// Return whether this interpreter is `manylinux` compatible.
pub fn manylinux_compatible(&self) -> bool {
self.manylinux_compatible
}
/// Return the [`PointerSize`] of the Python interpreter (i.e., 32- vs. 64-bit).
pub fn pointer_size(&self) -> PointerSize {
self.pointer_size
}
/// Return whether this is a Python 3.13+ freethreading Python, as specified by the sysconfig var
/// `Py_GIL_DISABLED`.
///
/// freethreading Python is incompatible with earlier native modules, re-introducing
/// abiflags with a `t` flag. <https://peps.python.org/pep-0703/#build-configuration-changes>
pub fn gil_disabled(&self) -> bool {
self.gil_disabled
}
/// Return the `--target` directory for this interpreter, if any.
pub fn target(&self) -> Option<&Target> {
self.target.as_ref()
}
/// Return the `--prefix` directory for this interpreter, if any.
pub fn prefix(&self) -> Option<&Prefix> {
self.prefix.as_ref()
}
/// Returns `true` if an [`Interpreter`] may be a `python-build-standalone` interpreter.
///
/// This method may return false positives, but it should not return false negatives. In other
/// words, if this method returns `true`, the interpreter _may_ be from
/// `python-build-standalone`; if it returns `false`, the interpreter is definitely _not_ from
/// `python-build-standalone`.
///
/// See: <https://github.com/astral-sh/python-build-standalone/issues/382>
#[cfg(unix)]
pub fn is_standalone(&self) -> bool {
self.standalone
}
/// Returns `true` if an [`Interpreter`] may be a `python-build-standalone` interpreter.
// TODO(john): Replace this approach with patching sysconfig on Windows to
// set `PYTHON_BUILD_STANDALONE=1`.`
#[cfg(windows)]
pub fn is_standalone(&self) -> bool {
self.standalone || (self.is_managed() && self.markers().implementation_name() == "cpython")
}
/// Return the [`Layout`] environment used to install wheels into this interpreter.
pub fn layout(&self) -> Layout {
Layout {
python_version: self.python_tuple(),
sys_executable: self.sys_executable().to_path_buf(),
os_name: self.markers.os_name().to_string(),
scheme: if let Some(target) = self.target.as_ref() {
target.scheme()
} else if let Some(prefix) = self.prefix.as_ref() {
prefix.scheme(&self.virtualenv)
} else {
Scheme {
purelib: self.purelib().to_path_buf(),
platlib: self.platlib().to_path_buf(),
scripts: self.scripts().to_path_buf(),
data: self.data().to_path_buf(),
include: if self.is_virtualenv() {
// If the interpreter is a venv, then the `include` directory has a different structure.
// See: https://github.com/pypa/pip/blob/0ad4c94be74cc24874c6feb5bb3c2152c398a18e/src/pip/_internal/locations/_sysconfig.py#L172
self.sys_prefix.join("include").join("site").join(format!(
"python{}.{}",
self.python_major(),
self.python_minor()
))
} else {
self.include().to_path_buf()
},
}
},
}
}
/// Returns an iterator over the `site-packages` directories inside the environment.
///
/// In most cases, `purelib` and `platlib` will be the same, and so the iterator will contain
/// a single element; however, in some distributions, they may be different.
///
/// Some distributions also create symbolic links from `purelib` to `platlib`; in such cases, we
/// still deduplicate the entries, returning a single path.
pub fn site_packages(&self) -> impl Iterator<Item = Cow<Path>> {
let target = self.target().map(Target::site_packages);
let prefix = self
.prefix()
.map(|prefix| prefix.site_packages(self.virtualenv()));
let interpreter = if target.is_none() && prefix.is_none() {
let purelib = self.purelib();
let platlib = self.platlib();
Some(std::iter::once(purelib).chain(
if purelib == platlib || is_same_file(purelib, platlib).unwrap_or(false) {
None
} else {
Some(platlib)
},
))
} else {
None
};
target
.into_iter()
.flatten()
.map(Cow::Borrowed)
.chain(prefix.into_iter().flatten().map(Cow::Owned))
.chain(interpreter.into_iter().flatten().map(Cow::Borrowed))
}
/// Check if the interpreter matches the given Python version.
///
/// If a patch version is present, we will require an exact match.
/// Otherwise, just the major and minor version numbers need to match.
pub fn satisfies(&self, version: &PythonVersion) -> bool {
if version.patch().is_some() {
version.version() == self.python_version()
} else {
(version.major(), version.minor()) == self.python_tuple()
}
}
/// Whether or not this Python interpreter is from a default Python executable name, like
/// `python`, `python3`, or `python.exe`.
pub(crate) fn has_default_executable_name(&self) -> bool {
let Some(file_name) = self.sys_executable().file_name() else {
return false;
};
let Some(name) = file_name.to_str() else {
return false;
};
VersionRequest::Default
.executable_names(None)
.into_iter()
.any(|default_name| name == default_name.to_string())
}
/// Grab a file lock for the environment to prevent concurrent writes across processes.
pub async fn lock(&self) -> Result<LockedFile, io::Error> {
if let Some(target) = self.target() {
// If we're installing into a `--target`, use a target-specific lockfile.
LockedFile::acquire(target.root().join(".lock"), target.root().user_display()).await
} else if let Some(prefix) = self.prefix() {
// Likewise, if we're installing into a `--prefix`, use a prefix-specific lockfile.
LockedFile::acquire(prefix.root().join(".lock"), prefix.root().user_display()).await
} else if self.is_virtualenv() {
// If the environment a virtualenv, use a virtualenv-specific lockfile.
LockedFile::acquire(
self.sys_prefix.join(".lock"),
self.sys_prefix.user_display(),
)
.await
} else {
// Otherwise, use a global lockfile.
LockedFile::acquire(
env::temp_dir().join(format!("uv-{}.lock", cache_digest(&self.sys_executable))),
self.sys_prefix.user_display(),
)
.await
}
}
}
/// Calls `fs_err::canonicalize` on Unix. On Windows, avoids attempting to resolve symlinks
/// but will resolve junctions if they are part of a trampoline target.
pub fn canonicalize_executable(path: impl AsRef<Path>) -> std::io::Result<PathBuf> {
let path = path.as_ref();
debug_assert!(
path.is_absolute(),
"path must be absolute: {}",
path.display()
);
#[cfg(windows)]
{
if let Ok(Some(launcher)) = uv_trampoline_builder::Launcher::try_from_path(path) {
Ok(dunce::canonicalize(launcher.python_path)?)
} else {
Ok(path.to_path_buf())
}
}
#[cfg(unix)]
fs_err::canonicalize(path)
}
/// The `EXTERNALLY-MANAGED` file in a Python installation.
///
/// See: <https://packaging.python.org/en/latest/specifications/externally-managed-environments/>
#[derive(Debug, Default, Clone)]
pub struct ExternallyManaged {
error: Option<String>,
}
impl ExternallyManaged {
/// Return the `EXTERNALLY-MANAGED` error message, if any.
pub fn into_error(self) -> Option<String> {
self.error
}
}
#[derive(Debug, Error)]
pub struct UnexpectedResponseError {
#[source]
pub(super) err: serde_json::Error,
pub(super) stdout: String,
pub(super) stderr: String,
pub(super) path: PathBuf,
}
impl Display for UnexpectedResponseError {
fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
write!(
f,
"Querying Python at `{}` returned an invalid response: {}",
self.path.display(),
self.err
)?;
let mut non_empty = false;
if !self.stdout.trim().is_empty() {
write!(f, "\n\n{}\n{}", "[stdout]".red(), self.stdout)?;
non_empty = true;
}
if !self.stderr.trim().is_empty() {
write!(f, "\n\n{}\n{}", "[stderr]".red(), self.stderr)?;
non_empty = true;
}
if non_empty {
writeln!(f)?;
}
Ok(())
}
}
#[derive(Debug, Error)]
pub struct StatusCodeError {
pub(super) code: ExitStatus,
pub(super) stdout: String,
pub(super) stderr: String,
pub(super) path: PathBuf,
}
impl Display for StatusCodeError {
fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
write!(
f,
"Querying Python at `{}` failed with exit status {}",
self.path.display(),
self.code
)?;
let mut non_empty = false;
if !self.stdout.trim().is_empty() {
write!(f, "\n\n{}\n{}", "[stdout]".red(), self.stdout)?;
non_empty = true;
}
if !self.stderr.trim().is_empty() {
write!(f, "\n\n{}\n{}", "[stderr]".red(), self.stderr)?;
non_empty = true;
}
if non_empty {
writeln!(f)?;
}
Ok(())
}
}
#[derive(Debug, Error)]
pub enum Error {
#[error("Failed to query Python interpreter")]
Io(#[from] io::Error),
#[error(transparent)]
BrokenSymlink(BrokenSymlink),
#[error("Python interpreter not found at `{0}`")]
NotFound(PathBuf),
#[error("Failed to query Python interpreter at `{path}`")]
SpawnFailed {
path: PathBuf,
#[source]
err: io::Error,
},
#[error("{0}")]
UnexpectedResponse(UnexpectedResponseError),
#[error("{0}")]
StatusCode(StatusCodeError),
#[error("Can't use Python at `{path}`")]
QueryScript {
#[source]
err: InterpreterInfoError,
path: PathBuf,
},
#[error("Failed to write to cache")]
Encode(#[from] rmp_serde::encode::Error),
}
#[derive(Debug, Error)]
pub struct BrokenSymlink {
pub path: PathBuf,
/// Whether the interpreter path looks like a virtual environment.
pub venv: bool,
}
impl Display for BrokenSymlink {
fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
write!(
f,
"Broken symlink at `{}`, was the underlying Python interpreter removed?",
self.path.user_display()
)?;
if self.venv {
write!(
f,
"\n\n{}{} Consider recreating the environment (e.g., with `{}`)",
"hint".bold().cyan(),
":".bold(),
"uv venv".green()
)?;
}
Ok(())
}
}
#[derive(Debug, Deserialize, Serialize)]
#[serde(tag = "result", rename_all = "lowercase")]
enum InterpreterInfoResult {
Error(InterpreterInfoError),
Success(Box<InterpreterInfo>),
}
#[derive(Debug, Error, Deserialize, Serialize)]
#[serde(tag = "kind", rename_all = "snake_case")]
pub enum InterpreterInfoError {
#[error("Could not detect a glibc or a musl libc (while running on Linux)")]
LibcNotFound,
#[error(
"Broken Python installation, `platform.mac_ver()` returned an empty value, please reinstall Python"
)]
BrokenMacVer,
#[error("Unknown operating system: `{operating_system}`")]
UnknownOperatingSystem { operating_system: String },
#[error("Python {python_version} is not supported. Please use Python 3.8 or newer.")]
UnsupportedPythonVersion { python_version: String },
#[error("Python executable does not support `-I` flag. Please use Python 3.8 or newer.")]
UnsupportedPython,
#[error(
"Python installation is missing `distutils`, which is required for packaging on older Python versions. Your system may package it separately, e.g., as `python{python_major}-distutils` or `python{python_major}.{python_minor}-distutils`."
)]
MissingRequiredDistutils {
python_major: usize,
python_minor: usize,
},
#[error("Only Pyodide is support for Emscripten Python")]
EmscriptenNotPyodide,
}
#[derive(Debug, Deserialize, Serialize, Clone)]
struct InterpreterInfo {
platform: Platform,
markers: MarkerEnvironment,
scheme: Scheme,
virtualenv: Scheme,
manylinux_compatible: bool,
sys_prefix: PathBuf,
sys_base_exec_prefix: PathBuf,
sys_base_prefix: PathBuf,
sys_base_executable: Option<PathBuf>,
sys_executable: PathBuf,
sys_path: Vec<PathBuf>,
stdlib: PathBuf,
standalone: bool,
pointer_size: PointerSize,
gil_disabled: bool,
}
impl InterpreterInfo {
/// Return the resolved [`InterpreterInfo`] for the given Python executable.
pub(crate) fn query(interpreter: &Path, cache: &Cache) -> Result<Self, Error> {
let tempdir = tempfile::tempdir_in(cache.root())?;
Self::setup_python_query_files(tempdir.path())?;
// Sanitize the path by (1) running under isolated mode (`-I`) to ignore any site packages
// modifications, and then (2) adding the path containing our query script to the front of
// `sys.path` so that we can import it.
let script = format!(
r#"import sys; sys.path = ["{}"] + sys.path; from python.get_interpreter_info import main; main()"#,
tempdir.path().escape_for_python()
);
let output = Command::new(interpreter)
.arg("-I") // Isolated mode.
.arg("-B") // Don't write bytecode.
.arg("-c")
.arg(script)
.output()
.map_err(|err| Error::SpawnFailed {
path: interpreter.to_path_buf(),
err,
})?;
if !output.status.success() {
let stderr = String::from_utf8_lossy(&output.stderr).trim().to_string();
// If the Python version is too old, we may not even be able to invoke the query script
if stderr.contains("Unknown option: -I") {
return Err(Error::QueryScript {
err: InterpreterInfoError::UnsupportedPython,
path: interpreter.to_path_buf(),
});
}
return Err(Error::StatusCode(StatusCodeError {
code: output.status,
stderr,
stdout: String::from_utf8_lossy(&output.stdout).trim().to_string(),
path: interpreter.to_path_buf(),
}));
}
let result: InterpreterInfoResult =
serde_json::from_slice(&output.stdout).map_err(|err| {
let stderr = String::from_utf8_lossy(&output.stderr).trim().to_string();
// If the Python version is too old, we may not even be able to invoke the query script
if stderr.contains("Unknown option: -I") {
Error::QueryScript {
err: InterpreterInfoError::UnsupportedPython,
path: interpreter.to_path_buf(),
}
} else {
Error::UnexpectedResponse(UnexpectedResponseError {
err,
stdout: String::from_utf8_lossy(&output.stdout).trim().to_string(),
stderr,
path: interpreter.to_path_buf(),
})
}
})?;
match result {
InterpreterInfoResult::Error(err) => Err(Error::QueryScript {
err,
path: interpreter.to_path_buf(),
}),
InterpreterInfoResult::Success(data) => Ok(*data),
}
}
/// Duplicate the directory structure we have in `../python` into a tempdir, so we can run
/// the Python probing scripts with `python -m python.get_interpreter_info` from that tempdir.
fn setup_python_query_files(root: &Path) -> Result<(), Error> {
let python_dir = root.join("python");
fs_err::create_dir(&python_dir)?;
fs_err::write(
python_dir.join("get_interpreter_info.py"),
include_str!("../python/get_interpreter_info.py"),
)?;
fs_err::write(
python_dir.join("__init__.py"),
include_str!("../python/__init__.py"),
)?;
let packaging_dir = python_dir.join("packaging");
fs_err::create_dir(&packaging_dir)?;
fs_err::write(
packaging_dir.join("__init__.py"),
include_str!("../python/packaging/__init__.py"),
)?;
fs_err::write(
packaging_dir.join("_elffile.py"),
include_str!("../python/packaging/_elffile.py"),
)?;
fs_err::write(
packaging_dir.join("_manylinux.py"),
include_str!("../python/packaging/_manylinux.py"),
)?;
fs_err::write(
packaging_dir.join("_musllinux.py"),
include_str!("../python/packaging/_musllinux.py"),
)?;
Ok(())
}
/// A wrapper around [`markers::query_interpreter_info`] to cache the computed markers.
///
/// Running a Python script is (relatively) expensive, and the markers won't change
/// unless the Python executable changes, so we use the executable's last modified
/// time as a cache key.
pub(crate) fn query_cached(executable: &Path, cache: &Cache) -> Result<Self, Error> {
let absolute = std::path::absolute(executable)?;
// Provide a better error message if the link is broken or the file does not exist. Since
// `canonicalize_executable` does not resolve the file on Windows, we must re-use this logic
// for the subsequent metadata read as we may not have actually resolved the path.
let handle_io_error = |err: io::Error| -> Error {
if err.kind() == io::ErrorKind::NotFound {
// Check if it looks like a venv interpreter where the underlying Python
// installation was removed.
if absolute
.symlink_metadata()
.is_ok_and(|metadata| metadata.is_symlink())
{
Error::BrokenSymlink(BrokenSymlink {
path: executable.to_path_buf(),
venv: uv_fs::is_virtualenv_executable(executable),
})
} else {
Error::NotFound(executable.to_path_buf())
}
} else {
err.into()
}
};
let canonical = canonicalize_executable(&absolute).map_err(handle_io_error)?;
let cache_entry = cache.entry(
CacheBucket::Interpreter,
// Shard interpreter metadata by host architecture, operating system, and version, to
// invalidate the cache (e.g.) on OS upgrades.
cache_digest(&(
ARCH,
sys_info::os_type().unwrap_or_default(),
sys_info::os_release().unwrap_or_default(),
)),
// We use the absolute path for the cache entry to avoid cache collisions for relative
// paths. But we don't want to query the executable with symbolic links resolved because
// that can change reported values, e.g., `sys.executable`. We include the canonical
// path in the cache entry as well, otherwise we can have cache collisions if an
// absolute path refers to different interpreters with matching ctimes, e.g., if you
// have a `.venv/bin/python` pointing to both Python 3.12 and Python 3.13 that were
// modified at the same time.
format!("{}.msgpack", cache_digest(&(&absolute, &canonical))),
);
// We check the timestamp of the canonicalized executable to check if an underlying
// interpreter has been modified.
let modified = Timestamp::from_path(canonical).map_err(handle_io_error)?;
// Read from the cache.
if cache
.freshness(&cache_entry, None, None)
.is_ok_and(Freshness::is_fresh)
{
if let Ok(data) = fs::read(cache_entry.path()) {
match rmp_serde::from_slice::<CachedByTimestamp<Self>>(&data) {
Ok(cached) => {
if cached.timestamp == modified {
trace!(
"Found cached interpreter info for Python {}, skipping query of: {}",
cached.data.markers.python_full_version(),
executable.user_display()
);
return Ok(cached.data);
}
trace!(
"Ignoring stale interpreter markers for: {}",
executable.user_display()
);
}
Err(err) => {
warn!(
"Broken interpreter cache entry at {}, removing: {err}",
cache_entry.path().user_display()
);
let _ = fs_err::remove_file(cache_entry.path());
}
}
}
}
// Otherwise, run the Python script.
trace!(
"Querying interpreter executable at {}",
executable.display()
);
let info = Self::query(executable, cache)?;
// If `executable` is a pyenv shim, a bash script that redirects to the activated
// python executable at another path, we're not allowed to cache the interpreter info.
if is_same_file(executable, &info.sys_executable).unwrap_or(false) {
fs::create_dir_all(cache_entry.dir())?;
write_atomic_sync(
cache_entry.path(),
rmp_serde::to_vec(&CachedByTimestamp {
timestamp: modified,
data: info.clone(),
})?,
)?;
}
Ok(info)
}
}
/// Find the Python executable that should be considered the "base" for a virtual environment.
///
/// Assumes that the provided executable is that of a standalone Python interpreter.
///
/// The strategy here mimics that of `getpath.py`: we search up the ancestor path to determine
/// whether a given executable will convert into a valid Python prefix; if not, we resolve the
/// symlink and try again.
///
/// This ensures that:
///
/// 1. We avoid using symlinks to arbitrary locations as the base Python executable. For example,
/// if a user symlinks a Python _executable_ to `/Users/user/foo`, we want to avoid using
/// `/Users/user` as `home`, since it's not a Python installation, and so the relevant libraries
/// and headers won't be found when it's used as the executable directory.
/// See: <https://github.com/python/cpython/blob/a03efb533a58fd13fb0cc7f4a5c02c8406a407bd/Modules/getpath.py#L367-L400>
///
/// 2. We use the "first" resolved symlink that _is_ a valid Python prefix, and thereby preserve
/// symlinks. For example, if a user symlinks a Python _installation_ to `/Users/user/foo`, such
/// that `/Users/user/foo/bin/python` is the resulting executable, we want to use `/Users/user/foo`
/// as `home`, rather than resolving to the symlink target. Concretely, this allows users to
/// symlink patch versions (like `cpython-3.12.6-macos-aarch64-none`) to minor version aliases
/// (like `cpython-3.12-macos-aarch64-none`) and preserve those aliases in the resulting virtual
/// environments.
///
/// See: <https://github.com/python/cpython/blob/a03efb533a58fd13fb0cc7f4a5c02c8406a407bd/Modules/getpath.py#L591-L594>
fn find_base_python(
executable: &Path,
major: u8,
minor: u8,
suffix: &str,
) -> Result<PathBuf, io::Error> {
/// Returns `true` if `path` is the root directory.
fn is_root(path: &Path) -> bool {
let mut components = path.components();
components.next() == Some(std::path::Component::RootDir) && components.next().is_none()
}
/// Determining whether `dir` is a valid Python prefix by searching for a "landmark".
///
/// See: <https://github.com/python/cpython/blob/a03efb533a58fd13fb0cc7f4a5c02c8406a407bd/Modules/getpath.py#L183>
fn is_prefix(dir: &Path, major: u8, minor: u8, suffix: &str) -> bool {
if cfg!(windows) {
dir.join("Lib").join("os.py").is_file()
} else {
dir.join("lib")
.join(format!("python{major}.{minor}{suffix}"))
.join("os.py")
.is_file()
}
}
let mut executable = Cow::Borrowed(executable);
loop {
debug!(
"Assessing Python executable as base candidate: {}",
executable.display()
);
// Determine whether this executable will produce a valid `home` for a virtual environment.
for prefix in executable.ancestors().take_while(|path| !is_root(path)) {
if is_prefix(prefix, major, minor, suffix) {
return Ok(executable.into_owned());
}
}
// If not, resolve the symlink.
let resolved = fs_err::read_link(&executable)?;
// If the symlink is relative, resolve it relative to the executable.
let resolved = if resolved.is_relative() {
if let Some(parent) = executable.parent() {
parent.join(resolved)
} else {
return Err(io::Error::other("Symlink has no parent directory"));
}
} else {
resolved
};
// Normalize the resolved path.
let resolved = uv_fs::normalize_absolute_path(&resolved)?;
executable = Cow::Owned(resolved);
}
}
#[cfg(unix)]
#[cfg(test)]
mod tests {
use std::str::FromStr;
use fs_err as fs;
use indoc::{formatdoc, indoc};
use tempfile::tempdir;
use uv_cache::Cache;
use uv_pep440::Version;
use crate::Interpreter;
#[test]
fn test_cache_invalidation() {
let mock_dir = tempdir().unwrap();
let mocked_interpreter = mock_dir.path().join("python");
let json = indoc! {r##"
{
"result": "success",
"platform": {
"os": {
"name": "manylinux",
"major": 2,
"minor": 38
},
"arch": "x86_64"
},
"manylinux_compatible": false,
"standalone": false,
"markers": {
"implementation_name": "cpython",
"implementation_version": "3.12.0",
"os_name": "posix",
"platform_machine": "x86_64",
"platform_python_implementation": "CPython",
"platform_release": "6.5.0-13-generic",
"platform_system": "Linux",
"platform_version": "#13-Ubuntu SMP PREEMPT_DYNAMIC Fri Nov 3 12:16:05 UTC 2023",
"python_full_version": "3.12.0",
"python_version": "3.12",
"sys_platform": "linux"
},
"sys_base_exec_prefix": "/home/ferris/.pyenv/versions/3.12.0",
"sys_base_prefix": "/home/ferris/.pyenv/versions/3.12.0",
"sys_prefix": "/home/ferris/projects/uv/.venv",
"sys_executable": "/home/ferris/projects/uv/.venv/bin/python",
"sys_path": [
"/home/ferris/.pyenv/versions/3.12.0/lib/python3.12/lib/python3.12",
"/home/ferris/.pyenv/versions/3.12.0/lib/python3.12/site-packages"
],
"stdlib": "/home/ferris/.pyenv/versions/3.12.0/lib/python3.12",
"scheme": {
"data": "/home/ferris/.pyenv/versions/3.12.0",
"include": "/home/ferris/.pyenv/versions/3.12.0/include",
"platlib": "/home/ferris/.pyenv/versions/3.12.0/lib/python3.12/site-packages",
"purelib": "/home/ferris/.pyenv/versions/3.12.0/lib/python3.12/site-packages",
"scripts": "/home/ferris/.pyenv/versions/3.12.0/bin"
},
"virtualenv": {
"data": "",
"include": "include",
"platlib": "lib/python3.12/site-packages",
"purelib": "lib/python3.12/site-packages",
"scripts": "bin"
},
"pointer_size": "64",
"gil_disabled": true
}
"##};
let cache = Cache::temp().unwrap().init().unwrap();
fs::write(
&mocked_interpreter,
formatdoc! {r"
#!/bin/sh
echo '{json}'
"},
)
.unwrap();
fs::set_permissions(
&mocked_interpreter,
std::os::unix::fs::PermissionsExt::from_mode(0o770),
)
.unwrap();
let interpreter = Interpreter::query(&mocked_interpreter, &cache).unwrap();
assert_eq!(
interpreter.markers.python_version().version,
Version::from_str("3.12").unwrap()
);
fs::write(
&mocked_interpreter,
formatdoc! {r"
#!/bin/sh
echo '{}'
", json.replace("3.12", "3.13")},
)
.unwrap();
let interpreter = Interpreter::query(&mocked_interpreter, &cache).unwrap();
assert_eq!(
interpreter.markers.python_version().version,
Version::from_str("3.13").unwrap()
);
}
}