Add uv tree --outdated (#8893)

## Summary

Similar to `pip list --outdated`, but for `uv tree`.

## Test Plan

Looks like:

```
foo v0.1.0
└── flask v2.0.0 (latest: v3.0.3)
    ├── click v8.1.7
    ├── itsdangerous v2.2.0
    ├── jinja2 v3.1.4
    │   └── markupsafe v3.0.2
    └── werkzeug v3.1.2
        └── markupsafe v3.0.2
```

With `(latest: v3.0.3)` in bold cyan.

crates/uv-cli/src/lib.rs

@@ -4802,6 +4802,10 @@ pub struct DisplayTreeArgs {
     /// display the packages that depend on the given package.
     #[arg(long, alias = "reverse")]
     pub invert: bool,
+
+    /// Show the latest available version of each package in the tree.
+    #[arg(long)]
+    pub outdated: bool,
 }
 
 #[derive(Args, Debug)]

crates/uv-distribution-filename/src/lib.rs

@@ -68,6 +68,13 @@ impl DistFilename {
         }
     }
 
+    pub fn into_version(self) -> Version {
+        match self {
+            Self::SourceDistFilename(filename) => filename.version,
+            Self::WheelFilename(filename) => filename.version,
+        }
+    }
+
     /// Whether the file is a `bdist_wheel` or an `sdist`.
     pub fn filetype(&self) -> &'static str {
         match self {

crates/uv-resolver/src/lib.rs

@@ -4,8 +4,8 @@ pub use exclude_newer::ExcludeNewer;
 pub use exclusions::Exclusions;
 pub use flat_index::{FlatDistributions, FlatIndex};
 pub use lock::{
-    InstallTarget, Lock, LockError, LockVersion, RequirementsTxtExport, ResolverManifest,
-    SatisfiesResult, TreeDisplay, VERSION,
+    InstallTarget, Lock, LockError, LockVersion, PackageMap, RequirementsTxtExport,
+    ResolverManifest, SatisfiesResult, TreeDisplay, VERSION,
 };
 pub use manifest::Manifest;
 pub use options::{Flexibility, Options, OptionsBuilder};

crates/uv-resolver/src/lock/map.rs

@@ -0,0 +1,37 @@
+use rustc_hash::FxHashMap;
+
+use crate::lock::{Package, PackageId};
+
+/// A map from package to values, indexed by [`PackageId`].
+#[derive(Debug, Clone)]
+pub struct PackageMap<T>(FxHashMap<PackageId, T>);
+
+impl<T> Default for PackageMap<T> {
+    fn default() -> Self {
+        Self(FxHashMap::default())
+    }
+}
+
+impl<T> PackageMap<T> {
+    /// Get a value by [`PackageId`].
+    pub(crate) fn get(&self, package_id: &PackageId) -> Option<&T> {
+        self.0.get(package_id)
+    }
+}
+
+impl<T> FromIterator<(Package, T)> for PackageMap<T> {
+    fn from_iter<I: IntoIterator<Item = (Package, T)>>(iter: I) -> Self {
+        Self(
+            iter.into_iter()
+                .map(|(package, value)| (package.id, value))
+                .collect(),
+        )
+    }
+}
+
+impl<T> Extend<(Package, T)> for PackageMap<T> {
+    fn extend<I: IntoIterator<Item = (Package, T)>>(&mut self, iter: I) {
+        self.0
+            .extend(iter.into_iter().map(|(package, value)| (package.id, value)));
+    }
+}

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

@@ -14,6 +14,7 @@ use std::sync::{Arc, LazyLock};
 use toml_edit::{value, Array, ArrayOfTables, InlineTable, Item, Table, Value};
 use url::Url;
 
+pub use crate::lock::map::PackageMap;
 pub use crate::lock::requirements_txt::RequirementsTxtExport;
 pub use crate::lock::target::InstallTarget;
 pub use crate::lock::tree::TreeDisplay;
@@ -47,6 +48,7 @@ use uv_types::{BuildContext, HashStrategy};
 use uv_workspace::dependency_groups::DependencyGroupError;
 use uv_workspace::Workspace;
 
+mod map;
 mod requirements_txt;
 mod target;
 mod tree;
@@ -2206,6 +2208,24 @@ impl Package {
         self.fork_markers.as_slice()
     }
 
+    /// Returns the [`IndexUrl`] for the package, if it is a registry source.
+    pub fn index(&self, root: &Path) -> Result<Option<IndexUrl>, LockError> {
+        match &self.id.source {
+            Source::Registry(RegistrySource::Url(url)) => {
+                let index = IndexUrl::from(VerbatimUrl::from_url(url.to_url()));
+                Ok(Some(index))
+            }
+            Source::Registry(RegistrySource::Path(path)) => {
+                let index = IndexUrl::from(
+                    VerbatimUrl::from_absolute_path(root.join(path))
+                        .map_err(LockErrorKind::RegistryVerbatimUrl)?,
+                );
+                Ok(Some(index))
+            }
+            _ => Ok(None),
+        }
+    }
+
     /// Returns all the hashes associated with this [`Package`].
     fn hashes(&self) -> Vec<HashDigest> {
         let mut hashes = Vec::new();

crates/uv-resolver/src/lock/tree.rs

@@ -2,24 +2,28 @@ use std::borrow::Cow;
 use std::collections::VecDeque;
 
 use itertools::Itertools;
+use owo_colors::OwoColorize;
 use petgraph::graph::{EdgeIndex, NodeIndex};
 use petgraph::prelude::EdgeRef;
 use petgraph::Direction;
 use rustc_hash::{FxHashMap, FxHashSet};
 
 use uv_configuration::DevGroupsManifest;
 use uv_normalize::{ExtraName, GroupName, PackageName};
+use uv_pep440::Version;
 use uv_pypi_types::ResolverMarkerEnvironment;
 
 use crate::lock::{Dependency, PackageId};
-use crate::Lock;
+use crate::{Lock, PackageMap};
 
 #[derive(Debug)]
 pub struct TreeDisplay<'env> {
     /// The constructed dependency graph.
     graph: petgraph::graph::Graph<&'env PackageId, Edge<'env>, petgraph::Directed>,
     /// The packages considered as roots of the dependency tree.
     roots: Vec<NodeIndex>,
+    /// The latest known version of each package.
+    latest: &'env PackageMap<Version>,
     /// Maximum display depth of the dependency tree.
     depth: usize,
     /// Whether to de-duplicate the displayed dependencies.
@@ -31,6 +35,7 @@ impl<'env> TreeDisplay<'env> {
     pub fn new(
         lock: &'env Lock,
         markers: Option<&'env ResolverMarkerEnvironment>,
+        latest: &'env PackageMap<Version>,
         depth: usize,
         prune: &[PackageName],
         packages: &[PackageName],
@@ -242,6 +247,7 @@ impl<'env> TreeDisplay<'env> {
         Self {
             graph,
             roots,
+            latest,
             depth,
             no_dedupe,
         }
@@ -306,6 +312,13 @@ impl<'env> TreeDisplay<'env> {
             }
         }
 
+        // Incorporate the latest version of the package, if known.
+        let line = if let Some(version) = self.latest.get(package_id) {
+            format!("{line} {}", format!("(latest: v{version})").bold().cyan())
+        } else {
+            line
+        };
+
         let mut dependencies = self
             .graph
             .edges_directed(cursor.node(), Direction::Outgoing)

crates/uv/src/commands/pip/latest.rs

@@ -0,0 +1,124 @@
+use uv_client::{RegistryClient, VersionFiles};
+use uv_distribution_filename::DistFilename;
+use uv_distribution_types::{IndexCapabilities, IndexUrl};
+use uv_normalize::PackageName;
+use uv_platform_tags::Tags;
+use uv_resolver::{ExcludeNewer, PrereleaseMode, RequiresPython};
+use uv_warnings::warn_user_once;
+
+/// A client to fetch the latest version of a package from an index.
+///
+/// The returned distribution is guaranteed to be compatible with the provided tags and Python
+/// requirement.
+#[derive(Debug)]
+pub(crate) struct LatestClient<'env> {
+    pub(crate) client: &'env RegistryClient,
+    pub(crate) capabilities: &'env IndexCapabilities,
+    pub(crate) prerelease: PrereleaseMode,
+    pub(crate) exclude_newer: Option<ExcludeNewer>,
+    pub(crate) tags: Option<&'env Tags>,
+    pub(crate) requires_python: &'env RequiresPython,
+}
+
+impl<'env> LatestClient<'env> {
+    /// Find the latest version of a package from an index.
+    pub(crate) async fn find_latest(
+        &self,
+        package: &PackageName,
+        index: Option<&IndexUrl>,
+    ) -> anyhow::Result<Option<DistFilename>, uv_client::Error> {
+        let mut latest: Option<DistFilename> = None;
+        for (_, archive) in self
+            .client
+            .simple(package, index, self.capabilities)
+            .await?
+        {
+            for datum in archive.iter().rev() {
+                // Find the first compatible distribution.
+                let files = rkyv::deserialize::<VersionFiles, rkyv::rancor::Error>(&datum.files)
+                    .expect("archived version files always deserializes");
+
+                // Determine whether there's a compatible wheel and/or source distribution.
+                let mut best = None;
+
+                for (filename, file) in files.all() {
+                    // Skip distributions uploaded after the cutoff.
+                    if let Some(exclude_newer) = self.exclude_newer {
+                        match file.upload_time_utc_ms.as_ref() {
+                            Some(&upload_time)
+                                if upload_time >= exclude_newer.timestamp_millis() =>
+                            {
+                                continue;
+                            }
+                            None => {
+                                warn_user_once!(
+                                    "{} is missing an upload date, but user provided: {exclude_newer}",
+                                    file.filename,
+                                );
+                            }
+                            _ => {}
+                        }
+                    }
+
+                    // Skip pre-release distributions.
+                    if !filename.version().is_stable() {
+                        if !matches!(self.prerelease, PrereleaseMode::Allow) {
+                            continue;
+                        }
+                    }
+
+                    // Skip distributions that are yanked.
+                    if file.yanked.is_some_and(|yanked| yanked.is_yanked()) {
+                        continue;
+                    }
+
+                    // Skip distributions that are incompatible with the Python requirement.
+                    if file
+                        .requires_python
+                        .as_ref()
+                        .is_some_and(|requires_python| {
+                            !self.requires_python.is_contained_by(requires_python)
+                        })
+                    {
+                        continue;
+                    }
+
+                    // Skip distributions that are incompatible with the current platform.
+                    if let DistFilename::WheelFilename(filename) = &filename {
+                        if self
+                            .tags
+                            .is_some_and(|tags| !filename.compatibility(tags).is_compatible())
+                        {
+                            continue;
+                        }
+                    }
+
+                    match filename {
+                        DistFilename::WheelFilename(_) => {
+                            best = Some(filename);
+                            break;
+                        }
+                        DistFilename::SourceDistFilename(_) => {
+                            if best.is_none() {
+                                best = Some(filename);
+                            }
+                        }
+                    }
+                }
+
+                match (latest.as_ref(), best) {
+                    (Some(current), Some(best)) => {
+                        if best.version() > current.version() {
+                            latest = Some(best);
+                        }
+                    }
+                    (None, Some(best)) => {
+                        latest = Some(best);
+                    }
+                    _ => {}
+                }
+            }
+        }
+        Ok(latest)
+    }
+}