Add basic uv sync and uv lock commands (#3436)

## Summary

These aren't intended for production use; instead, I'm just trying to
frame out the overall data flows and code-sharing for these commands. We
now have `uv sync` (sync the environment to match the lockfile, without
refreshing or resolving) and `uv lock` (generate the lockfile). Both
_require_ a virtual environment to exist (something we should change).
`uv sync`, `uv run`, and `uv lock` all share code for the underlying
subroutines (resolution and installation), so the commands themselves
are relatively small (~100 lines) and mostly consist of reading
arguments and such.

`uv lock` and `uv sync` don't actually really work yet, because we have
no way to include the project itself in the lockfile (that's a TODO in
the lockfile implementation).

Closes #3432.

crates/uv-types/src/builds.rs

@@ -1,8 +1,9 @@
 use uv_interpreter::PythonEnvironment;
 
 /// Whether to enforce build isolation when building source distributions.
-#[derive(Debug, Copy, Clone)]
+#[derive(Debug, Default, Copy, Clone)]
 pub enum BuildIsolation<'a> {
+    #[default]
     Isolated,
     Shared(&'a PythonEnvironment),
 }

crates/uv-types/src/hash.rs

@@ -11,9 +11,10 @@ use pep508_rs::MarkerEnvironment;
 use pypi_types::{HashDigest, HashError};
 use uv_normalize::PackageName;
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Default, Clone)]
 pub enum HashStrategy {
     /// No hash policy is specified.
+    #[default]
     None,
     /// Hashes should be generated (specifically, a SHA-256 hash), but not validated.
     Generate,

crates/uv/src/cli.rs

@@ -133,8 +133,15 @@ pub(crate) enum Commands {
     /// Clear the cache, removing all entries or those linked to specific packages.
     #[command(hide = true)]
     Clean(CleanArgs),
+    /// Run a command in the project environment.
     #[clap(hide = true)]
     Run(RunArgs),
+    /// Sync the project's dependencies with the environment.
+    #[clap(hide = true)]
+    Sync(SyncArgs),
+    /// Resolve the project requirements into a lockfile.
+    #[clap(hide = true)]
+    Lock(LockArgs),
     /// Display uv's version
     Version {
         #[arg(long, value_enum, default_value = "text")]
@@ -1852,6 +1859,54 @@ pub(crate) struct RunArgs {
     pub(crate) python: Option<String>,
 }
 
+#[derive(Args)]
+#[allow(clippy::struct_excessive_bools)]
+pub(crate) struct SyncArgs {
+    /// The Python interpreter to use to build the run environment.
+    ///
+    /// By default, `uv` uses the virtual environment in the current working directory or any parent
+    /// directory, falling back to searching for a Python executable in `PATH`. The `--python`
+    /// option allows you to specify a different interpreter.
+    ///
+    /// Supported formats:
+    /// - `3.10` looks for an installed Python 3.10 using `py --list-paths` on Windows, or
+    ///   `python3.10` on Linux and macOS.
+    /// - `python3.10` or `python.exe` looks for a binary with the given name in `PATH`.
+    /// - `/home/ferris/.local/bin/python3.10` uses the exact Python at the given path.
+    #[arg(
+        long,
+        short,
+        env = "UV_PYTHON",
+        verbatim_doc_comment,
+        group = "discovery"
+    )]
+    pub(crate) python: Option<String>,
+}
+
+#[derive(Args)]
+#[allow(clippy::struct_excessive_bools)]
+pub(crate) struct LockArgs {
+    /// The Python interpreter to use to build the run environment.
+    ///
+    /// By default, `uv` uses the virtual environment in the current working directory or any parent
+    /// directory, falling back to searching for a Python executable in `PATH`. The `--python`
+    /// option allows you to specify a different interpreter.
+    ///
+    /// Supported formats:
+    /// - `3.10` looks for an installed Python 3.10 using `py --list-paths` on Windows, or
+    ///   `python3.10` on Linux and macOS.
+    /// - `python3.10` or `python.exe` looks for a binary with the given name in `PATH`.
+    /// - `/home/ferris/.local/bin/python3.10` uses the exact Python at the given path.
+    #[arg(
+        long,
+        short,
+        env = "UV_PYTHON",
+        verbatim_doc_comment,
+        group = "discovery"
+    )]
+    pub(crate) python: Option<String>,
+}
+
 #[derive(Args)]
 #[allow(clippy::struct_excessive_bools)]
 struct AddArgs {

crates/uv/src/commands/mod.rs

@@ -16,7 +16,6 @@ pub(crate) use pip_list::pip_list;
 pub(crate) use pip_show::pip_show;
 pub(crate) use pip_sync::pip_sync;
 pub(crate) use pip_uninstall::pip_uninstall;
-pub(crate) use run::run;
 #[cfg(feature = "self-update")]
 pub(crate) use self_update::self_update;
 use uv_cache::Cache;
@@ -26,6 +25,9 @@ use uv_interpreter::PythonEnvironment;
 use uv_normalize::PackageName;
 pub(crate) use venv::venv;
 pub(crate) use version::version;
+pub(crate) use workspace::lock::lock;
+pub(crate) use workspace::run::run;
+pub(crate) use workspace::sync::sync;
 
 use crate::printer::Printer;
 
@@ -41,11 +43,11 @@ mod pip_show;
 mod pip_sync;
 mod pip_uninstall;
 mod reporters;
-mod run;
 #[cfg(feature = "self-update")]
 mod self_update;
 mod venv;
 mod version;
+mod workspace;
 
 #[derive(Copy, Clone)]
 pub(crate) enum ExitStatus {