Move architecture and operating system probing to Python (#2381)

The architecture of uv does not necessarily match that of the python
interpreter (#2326). In cross compiling/testing scenarios the operating
system can also mismatch. To solve this, we move arch and os detection
to python, vendoring the relevant pypa/packaging code, preventing
mismatches between what the python interpreter was compiled for and what
uv was compiled for.

To make the scripts more manageable, they are now a directory in a
tempdir and we run them with `python -m` . I've simplified the
pypa/packaging code since we're still building the tags in rust. A
`Platform` is now instantiated by querying the python interpreter for
its platform. The pypa/packaging files are copied verbatim for easier
updates except a `lru_cache()` python 3.7 backport.

Error handling is done by a `"result": "success|error"` field that allow
passing error details to rust:

```console
$ uv venv --no-cache
  × Can't use Python at `/home/konsti/projects/uv/.venv/bin/python3`
  ╰─▶ Unknown operation system `linux`
```

I've used the [maturin sysconfig
collection](855f6d2cb1/sysconfig)
as reference. I'm unsure how to test these changes across the wide
variety of platforms.

Fixes #2326

crates/uv-dev/src/build.rs

@@ -6,7 +6,6 @@ use clap::Parser;
 use fs_err as fs;
 
 use distribution_types::IndexLocations;
-use platform_host::Platform;
 use rustc_hash::FxHashMap;
 use uv_build::{SourceBuild, SourceBuildContext};
 use uv_cache::{Cache, CacheArgs};
@@ -56,8 +55,7 @@ pub(crate) async fn build(args: BuildArgs) -> Result<PathBuf> {
 
     let cache = Cache::try_from(args.cache_args)?;
 
-    let platform = Platform::current()?;
-    let venv = PythonEnvironment::from_virtualenv(platform, &cache)?;
+    let venv = PythonEnvironment::from_virtualenv(&cache)?;
     let client = RegistryClientBuilder::new(cache.clone()).build();
     let index_urls = IndexLocations::default();
     let flat_index = FlatIndex::default();

crates/uv-dev/src/compile.rs

@@ -1,7 +1,6 @@
 use std::path::PathBuf;
 
 use clap::Parser;
-use platform_host::Platform;
 use tracing::info;
 use uv_cache::{Cache, CacheArgs};
 use uv_interpreter::PythonEnvironment;
@@ -21,8 +20,7 @@ pub(crate) async fn compile(args: CompileArgs) -> anyhow::Result<()> {
     let interpreter = if let Some(python) = args.python {
         python
     } else {
-        let platform = Platform::current()?;
-        let venv = PythonEnvironment::from_virtualenv(platform, &cache)?;
+        let venv = PythonEnvironment::from_virtualenv(&cache)?;
         venv.python_executable().to_path_buf()
     };
 

crates/uv-dev/src/install_many.rs

@@ -14,7 +14,6 @@ use distribution_types::{
 };
 use install_wheel_rs::linker::LinkMode;
 use pep508_rs::Requirement;
-use platform_host::Platform;
 use platform_tags::Tags;
 use uv_cache::{Cache, CacheArgs};
 use uv_client::{FlatIndex, RegistryClient, RegistryClientBuilder};
@@ -55,8 +54,7 @@ pub(crate) async fn install_many(args: InstallManyArgs) -> Result<()> {
     info!("Got {} requirements", requirements.len());
 
     let cache = Cache::try_from(args.cache_args)?;
-    let platform = Platform::current()?;
-    let venv = PythonEnvironment::from_virtualenv(platform, &cache)?;
+    let venv = PythonEnvironment::from_virtualenv(&cache)?;
     let client = RegistryClientBuilder::new(cache.clone()).build();
     let index_locations = IndexLocations::default();
     let flat_index = FlatIndex::default();

crates/uv-dev/src/resolve_cli.rs

@@ -11,7 +11,6 @@ use petgraph::dot::{Config as DotConfig, Dot};
 
 use distribution_types::{FlatIndexLocation, IndexLocations, IndexUrl, Resolution};
 use pep508_rs::Requirement;
-use platform_host::Platform;
 use uv_cache::{Cache, CacheArgs};
 use uv_client::{FlatIndex, FlatIndexClient, RegistryClientBuilder};
 use uv_dispatch::BuildDispatch;
@@ -54,8 +53,7 @@ pub(crate) struct ResolveCliArgs {
 pub(crate) async fn resolve_cli(args: ResolveCliArgs) -> Result<()> {
     let cache = Cache::try_from(args.cache_args)?;
 
-    let platform = Platform::current()?;
-    let venv = PythonEnvironment::from_virtualenv(platform, &cache)?;
+    let venv = PythonEnvironment::from_virtualenv(&cache)?;
     let index_locations =
         IndexLocations::new(args.index_url, args.extra_index_url, args.find_links, false);
     let client = RegistryClientBuilder::new(cache.clone())

crates/uv-dev/src/resolve_many.rs

@@ -13,7 +13,6 @@ use tracing_indicatif::span_ext::IndicatifSpanExt;
 use distribution_types::IndexLocations;
 use pep440_rs::{Version, VersionSpecifier, VersionSpecifiers};
 use pep508_rs::{Requirement, VersionOrUrl};
-use platform_host::Platform;
 use uv_cache::{Cache, CacheArgs};
 use uv_client::{FlatIndex, OwnedArchive, RegistryClient, RegistryClientBuilder};
 use uv_dispatch::BuildDispatch;
@@ -72,8 +71,7 @@ pub(crate) async fn resolve_many(args: ResolveManyArgs) -> Result<()> {
     };
     let total = requirements.len();
 
-    let platform = Platform::current()?;
-    let venv = PythonEnvironment::from_virtualenv(platform, &cache)?;
+    let venv = PythonEnvironment::from_virtualenv(&cache)?;
     let in_flight = InFlight::default();
     let client = RegistryClientBuilder::new(cache.clone()).build();