Add PEP 751 support to uv pip compile

Author: charliermarsh

crates/uv-cli/src/lib.rs

@@ -1075,13 +1075,22 @@ pub struct PipCompileArgs {
     #[arg(long, group = "sources")]
     pub group: Vec<PipGroupName>,
 
-    /// Write the compiled requirements to the given `requirements.txt` file.
+    /// Write the compiled requirements to the given `requirements.txt` or `pylock.toml` file.
     ///
     /// If the file already exists, the existing versions will be preferred when resolving
     /// dependencies, unless `--upgrade` is also specified.
     #[arg(long, short)]
     pub output_file: Option<PathBuf>,
 
+    /// The format in which the resolution should be output.
+    ///
+    /// Supports both `requirements.txt` and `pylock.toml` (PEP 751) output formats.
+    ///
+    /// uv will infer the output format from the file extension of the output file, if
+    /// provided. Otherwise, defaults to `requirements.txt`.
+    #[arg(long, value_enum)]
+    pub format: Option<ExportFormat>,
+
     /// Include extras in the output file.
     ///
     /// By default, uv strips extras, as any packages pulled in by the extras are already included

crates/uv-requirements/src/upgrade.rs

@@ -7,7 +7,7 @@ use uv_configuration::Upgrade;
 use uv_fs::CWD;
 use uv_git::ResolvedRepositoryReference;
 use uv_requirements_txt::RequirementsTxt;
-use uv_resolver::{Lock, LockError, Preference, PreferenceError};
+use uv_resolver::{Lock, LockError, Preference, PreferenceError, PylockToml, PylockTomlError};
 
 #[derive(Debug, Default)]
 pub struct LockedRequirements {
@@ -17,21 +17,26 @@ pub struct LockedRequirements {
     pub git: Vec<ResolvedRepositoryReference>,
 }
 
+impl LockedRequirements {
+    /// Create a [`LockedRequirements`] from a list of preferences.
+    pub fn from_preferences(preferences: Vec<Preference>) -> Self {
+        Self {
+            preferences,
+            ..LockedRequirements::default()
+        }
+    }
+}
+
 /// Load the preferred requirements from an existing `requirements.txt`, applying the upgrade strategy.
 pub async fn read_requirements_txt(
-    output_file: Option<&Path>,
+    output_file: &Path,
     upgrade: &Upgrade,
 ) -> Result<Vec<Preference>> {
     // As an optimization, skip reading the lockfile is we're upgrading all packages anyway.
     if upgrade.is_all() {
         return Ok(Vec::new());
     }
 
-    // If the lockfile doesn't exist, don't respect any pinned versions.
-    let Some(output_file) = output_file.filter(|path| path.exists()) else {
-        return Ok(Vec::new());
-    };
-
     // Parse the requirements from the lockfile.
     let requirements_txt = RequirementsTxt::parse(
         output_file,
@@ -95,3 +100,40 @@ pub fn read_lock_requirements(
 
     Ok(LockedRequirements { preferences, git })
 }
+
+/// Load the preferred requirements from an existing `pylock.toml` file, applying the upgrade strategy.
+pub async fn read_pylock_toml_requirements(
+    output_file: &Path,
+    upgrade: &Upgrade,
+) -> Result<LockedRequirements, PylockTomlError> {
+    // As an optimization, skip iterating over the lockfile is we're upgrading all packages anyway.
+    if upgrade.is_all() {
+        return Ok(LockedRequirements::default());
+    }
+
+    // Read the `pylock.toml` from disk, and deserialize it from TOML.
+    let content = fs_err::tokio::read_to_string(&output_file).await?;
+    let lock = toml::from_str::<PylockToml>(&content)?;
+
+    let mut preferences = Vec::new();
+    let mut git = Vec::new();
+
+    for package in &lock.packages {
+        // Skip the distribution if it's not included in the upgrade strategy.
+        if upgrade.contains(&package.name) {
+            continue;
+        }
+
+        // Map each entry in the lockfile to a preference.
+        if let Some(preference) = Preference::from_pylock_toml(package)? {
+            preferences.push(preference);
+        }
+
+        // Map each entry in the lockfile to a Git SHA.
+        if let Some(git_ref) = package.as_git_ref() {
+            git.push(git_ref);
+        }
+    }
+
+    Ok(LockedRequirements { preferences, git })
+}

crates/uv-resolver/src/lib.rs

@@ -5,7 +5,7 @@ pub use exclusions::Exclusions;
 pub use flat_index::{FlatDistributions, FlatIndex};
 pub use fork_strategy::ForkStrategy;
 pub use lock::{
-    Installable, Lock, LockError, LockVersion, Package, PackageMap, PylockToml,
+    Installable, Lock, LockError, LockVersion, Package, PackageMap, PylockToml, PylockTomlError,
     RequirementsTxtExport, ResolverManifest, SatisfiesResult, TreeDisplay, VERSION,
 };
 pub use manifest::Manifest;

crates/uv-resolver/src/lock/export/mod.rs

@@ -14,7 +14,8 @@ use uv_pep508::MarkerTree;
 use uv_pypi_types::ConflictItem;
 
 use crate::graph_ops::{marker_reachability, Reachable};
-pub use crate::lock::export::pylock_toml::PylockToml;
+pub(crate) use crate::lock::export::pylock_toml::PylockTomlPackage;
+pub use crate::lock::export::pylock_toml::{PylockToml, PylockTomlError};
 pub use crate::lock::export::requirements_txt::RequirementsTxtExport;
 use crate::universal_marker::resolve_conflicts;
 use crate::{Installable, Package};