Use a boxed slice for extras and groups (#12391)

## Summary

A very common struct, and these are immutable. Easy to optimize.

Author: charliermarsh

crates/uv-configuration/src/constraints.rs

@@ -28,7 +28,7 @@ impl Constraints {
                 .or_default()
                 .push(Requirement {
                     // We add and apply constraints independent of their extras.
-                    extras: vec![],
+                    extras: Box::new([]),
                     ..requirement
                 });
         }

crates/uv-distribution-types/src/requirement.rs

@@ -5,16 +5,15 @@ use std::str::FromStr;
 
 use thiserror::Error;
 use url::Url;
-use uv_distribution_filename::DistExtension;
 
+use uv_distribution_filename::DistExtension;
 use uv_fs::{relative_to, PortablePath, PortablePathBuf, CWD};
 use uv_git_types::{GitOid, GitReference, GitUrl, GitUrlParseError, OidParseError};
 use uv_normalize::{ExtraName, GroupName, PackageName};
 use uv_pep440::VersionSpecifiers;
 use uv_pep508::{
     marker, MarkerEnvironment, MarkerTree, RequirementOrigin, VerbatimUrl, VersionOrUrl,
 };
-
 use uv_pypi_types::{
     ConflictItem, Hashes, ParsedArchiveUrl, ParsedDirectoryUrl, ParsedGitUrl, ParsedPathUrl,
     ParsedUrl, ParsedUrlError, VerbatimParsedUrl,
@@ -45,10 +44,10 @@ pub enum RequirementError {
 #[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 pub struct Requirement {
     pub name: PackageName,
-    #[serde(skip_serializing_if = "Vec::is_empty", default)]
-    pub extras: Vec<ExtraName>,
-    #[serde(skip_serializing_if = "Vec::is_empty", default)]
-    pub groups: Vec<GroupName>,
+    #[serde(skip_serializing_if = "<[ExtraName]>::is_empty", default)]
+    pub extras: Box<[ExtraName]>,
+    #[serde(skip_serializing_if = "<[GroupName]>::is_empty", default)]
+    pub groups: Box<[GroupName]>,
     #[serde(
         skip_serializing_if = "marker::ser::is_empty",
         serialize_with = "marker::ser::serialize",
@@ -290,7 +289,7 @@ impl From<uv_pep508::Requirement<VerbatimParsedUrl>> for Requirement {
         };
         Requirement {
             name: requirement.name,
-            groups: vec![],
+            groups: Box::new([]),
             extras: requirement.extras,
             marker: requirement.marker,
             source,
@@ -917,8 +916,8 @@ mod tests {
     fn roundtrip() {
         let requirement = Requirement {
             name: "foo".parse().unwrap(),
-            extras: vec![],
-            groups: vec![],
+            extras: Box::new([]),
+            groups: Box::new([]),
             marker: MarkerTree::TRUE,
             source: RequirementSource::Registry {
                 specifier: ">1,<2".parse().unwrap(),
@@ -939,8 +938,8 @@ mod tests {
         };
         let requirement = Requirement {
             name: "foo".parse().unwrap(),
-            extras: vec![],
-            groups: vec![],
+            extras: Box::new([]),
+            groups: Box::new([]),
             marker: MarkerTree::TRUE,
             source: RequirementSource::Directory {
                 install_path: PathBuf::from(path),

crates/uv-distribution-types/src/specified_requirement.rs

@@ -69,8 +69,8 @@ impl UnresolvedRequirement {
     /// Returns the extras for the requirement.
     pub fn extras(&self) -> &[ExtraName] {
         match self {
-            Self::Named(requirement) => requirement.extras.as_slice(),
-            Self::Unnamed(requirement) => requirement.extras.as_slice(),
+            Self::Named(requirement) => &requirement.extras,
+            Self::Unnamed(requirement) => &requirement.extras,
         }
     }
 

crates/uv-distribution/src/metadata/lowering.rs

@@ -324,7 +324,7 @@ impl LoweredRequirement {
                     Ok(Self(Requirement {
                         name: requirement.name.clone(),
                         extras: requirement.extras.clone(),
-                        groups: vec![],
+                        groups: Box::new([]),
                         marker,
                         source,
                         origin: requirement.origin.clone(),
@@ -466,7 +466,7 @@ impl LoweredRequirement {
                     Ok(Self(Requirement {
                         name: requirement.name.clone(),
                         extras: requirement.extras.clone(),
-                        groups: vec![],
+                        groups: Box::new([]),
                         marker,
                         source,
                         origin: requirement.origin.clone(),

crates/uv-distribution/src/metadata/requires_dist.rs

@@ -426,7 +426,7 @@ impl FlatRequiresDist {
                 if !req.source.is_empty() {
                     flattened.push(Requirement {
                         name: req.name.clone(),
-                        extras: vec![],
+                        extras: Box::new([]),
                         groups: req.groups.clone(),
                         source: req.source.clone(),
                         origin: req.origin.clone(),

crates/uv-pep508/src/lib.rs

@@ -124,7 +124,7 @@ pub struct Requirement<T: Pep508Url = VerbatimUrl> {
     pub name: PackageName,
     /// The list of extras such as `security`, `tests` in
     /// `requests [security,tests] >= 2.8.1, == 2.8.* ; python_version > "3.8"`.
-    pub extras: Vec<ExtraName>,
+    pub extras: Box<[ExtraName]>,
     /// The version specifier such as `>= 2.8.1`, `== 2.8.*` in
     /// `requests [security,tests] >= 2.8.1, == 2.8.* ; python_version > "3.8"`.
     /// or a URL.
@@ -964,7 +964,7 @@ fn parse_pep508_requirement<T: Pep508Url>(
 
     Ok(Requirement {
         name,
-        extras,
+        extras: extras.into_boxed_slice(),
         version_or_url: requirement_kind,
         marker: marker.unwrap_or_default(),
         origin: None,
@@ -1058,10 +1058,10 @@ mod tests {
         assert_eq!(input, requests.to_string());
         let expected = Requirement {
             name: PackageName::from_str("requests").unwrap(),
-            extras: vec![
+            extras: Box::new([
                 ExtraName::from_str("security").unwrap(),
                 ExtraName::from_str("tests").unwrap(),
-            ],
+            ]),
             version_or_url: Some(VersionOrUrl::VersionSpecifier(
                 [
                     VersionSpecifier::from_pattern(
@@ -1126,7 +1126,7 @@ mod tests {
     fn direct_url_no_extras() {
         let numpy = crate::UnnamedRequirement::<VerbatimUrl>::from_str("https://files.pythonhosted.org/packages/28/4a/46d9e65106879492374999e76eb85f87b15328e06bd1550668f79f7b18c6/numpy-1.26.4-cp312-cp312-win32.whl").unwrap();
         assert_eq!(numpy.url.to_string(), "https://files.pythonhosted.org/packages/28/4a/46d9e65106879492374999e76eb85f87b15328e06bd1550668f79f7b18c6/numpy-1.26.4-cp312-cp312-win32.whl");
-        assert_eq!(numpy.extras, vec![]);
+        assert_eq!(*numpy.extras, []);
     }
 
     #[test]
@@ -1140,7 +1140,7 @@ mod tests {
             numpy.url.to_string(),
             "file:///path/to/numpy-1.26.4-cp312-cp312-win32.whl"
         );
-        assert_eq!(numpy.extras, vec![ExtraName::from_str("dev").unwrap()]);
+        assert_eq!(*numpy.extras, [ExtraName::from_str("dev").unwrap()]);
     }
 
     #[test]
@@ -1154,7 +1154,7 @@ mod tests {
             numpy.url.to_string(),
             "file:///C:/path/to/numpy-1.26.4-cp312-cp312-win32.whl"
         );
-        assert_eq!(numpy.extras, vec![ExtraName::from_str("dev").unwrap()]);
+        assert_eq!(*numpy.extras, [ExtraName::from_str("dev").unwrap()]);
     }
 
     #[test]
@@ -1244,15 +1244,15 @@ mod tests {
     #[test]
     fn error_extras1() {
         let numpy = Requirement::<Url>::from_str("black[d]").unwrap();
-        assert_eq!(numpy.extras, vec![ExtraName::from_str("d").unwrap()]);
+        assert_eq!(*numpy.extras, [ExtraName::from_str("d").unwrap()]);
     }
 
     #[test]
     fn error_extras2() {
         let numpy = Requirement::<Url>::from_str("black[d,jupyter]").unwrap();
         assert_eq!(
-            numpy.extras,
-            vec![
+            *numpy.extras,
+            [
                 ExtraName::from_str("d").unwrap(),
                 ExtraName::from_str("jupyter").unwrap(),
             ]
@@ -1262,13 +1262,13 @@ mod tests {
     #[test]
     fn empty_extras() {
         let black = Requirement::<Url>::from_str("black[]").unwrap();
-        assert_eq!(black.extras, vec![]);
+        assert_eq!(*black.extras, []);
     }
 
     #[test]
     fn empty_extras_with_spaces() {
         let black = Requirement::<Url>::from_str("black[  ]").unwrap();
-        assert_eq!(black.extras, vec![]);
+        assert_eq!(*black.extras, []);
     }
 
     #[test]
@@ -1325,7 +1325,7 @@ mod tests {
         let url = "https://github.com/pypa/pip/archive/1.3.1.zip#sha1=da9234ee9982d4bbb3c72346a6de940a148ea686";
         let expected = Requirement {
             name: PackageName::from_str("pip").unwrap(),
-            extras: vec![],
+            extras: Box::new([]),
             marker: MarkerTree::TRUE,
             version_or_url: Some(VersionOrUrl::Url(Url::parse(url).unwrap())),
             origin: None,

crates/uv-pep508/src/unnamed.rs

@@ -71,7 +71,7 @@ pub struct UnnamedRequirement<Url: UnnamedRequirementUrl = VerbatimUrl> {
     pub url: Url,
     /// The list of extras such as `security`, `tests` in
     /// `requests [security,tests] >= 2.8.1, == 2.8.* ; python_version > "3.8"`.
-    pub extras: Vec<ExtraName>,
+    pub extras: Box<[ExtraName]>,
     /// The markers such as `python_version > "3.8"` in
     /// `requests [security,tests] >= 2.8.1, == 2.8.* ; python_version > "3.8"`.
     /// Those are a nested and/or tree.
@@ -193,7 +193,7 @@ fn parse_unnamed_requirement<Url: UnnamedRequirementUrl>(
 
     Ok(UnnamedRequirement {
         url,
-        extras,
+        extras: extras.into_boxed_slice(),
         marker: marker.unwrap_or_default(),
         origin: None,
     })

crates/uv-requirements/src/extras.rs

@@ -119,7 +119,7 @@ impl<'a, Context: BuildContext> ExtrasResolver<'a, Context> {
         };
 
         Ok(Requirement {
-            extras,
+            extras: extras.into_boxed_slice(),
             ..requirement
         })
     }

crates/uv-requirements/src/specification.rs

@@ -203,7 +203,7 @@ impl RequirementsSpecification {
                     requirements: vec![UnresolvedRequirementSpecification {
                         requirement: UnresolvedRequirement::Unnamed(UnnamedRequirement {
                             url: VerbatimParsedUrl::parse_absolute_path(path)?,
-                            extras: vec![],
+                            extras: Box::new([]),
                             marker: MarkerTree::TRUE,
                             origin: None,
                         }),

crates/uv-resolver/src/pubgrub/dependencies.rs

@@ -58,14 +58,9 @@ impl PubGrubDependency {
             } else {
                 Either::Right(iter::empty())
             };
+            let extras = requirement.extras.to_vec();
             Either::Left(Either::Left(
-                base.chain(
-                    requirement
-                        .extras
-                        .clone()
-                        .into_iter()
-                        .map(|extra| (Some(extra), None)),
-                ),
+                base.chain(extras.into_iter().map(|extra| (Some(extra), None))),
             ))
         } else if !requirement.groups.is_empty() {
             let base = if requirement
@@ -77,14 +72,9 @@ impl PubGrubDependency {
             } else {
                 Either::Right(iter::empty())
             };
+            let groups = requirement.groups.to_vec();
             Either::Left(Either::Right(
-                base.chain(
-                    requirement
-                        .groups
-                        .clone()
-                        .into_iter()
-                        .map(|group| (None, Some(group))),
-                ),
+                base.chain(groups.into_iter().map(|group| (None, Some(group)))),
             ))
         } else {
             Either::Right(iter::once((None, None)))

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

@@ -1672,7 +1672,7 @@ impl<InstalledPackages: InstalledPackagesProvider> ResolverState<InstalledPackag
                 );
 
                 requirements
-                    .flat_map(|requirement| {
+                    .flat_map(move |requirement| {
                         PubGrubDependency::from_requirement(
                             &self.conflicts,
                             requirement,
@@ -1952,7 +1952,7 @@ impl<InstalledPackages: InstalledPackagesProvider> ResolverState<InstalledPackag
                 if name == Some(&req.name) && !req.source.is_empty() {
                     self_constraints.push(Requirement {
                         name: req.name.clone(),
-                        extras: vec![],
+                        extras: Box::new([]),
                         groups: req.groups.clone(),
                         source: req.source.clone(),
                         origin: req.origin.clone(),

crates/uv-types/src/requirements.rs

@@ -9,16 +9,16 @@ use uv_normalize::ExtraName;
 #[derive(Debug, Clone)]
 pub struct RequestedRequirements {
     /// The set of extras included on the originating requirement.
-    extras: Vec<ExtraName>,
+    extras: Box<[ExtraName]>,
     /// The set of requirements that were requested by the originating requirement.
-    requirements: Vec<Requirement>,
+    requirements: Box<[Requirement]>,
     /// Whether the dependencies were direct or transitive.
     direct: bool,
 }
 
 impl RequestedRequirements {
     /// Instantiate a [`RequestedRequirements`] with the given `extras` and `requirements`.
-    pub fn new(extras: Vec<ExtraName>, requirements: Vec<Requirement>, direct: bool) -> Self {
+    pub fn new(extras: Box<[ExtraName]>, requirements: Box<[Requirement]>, direct: bool) -> Self {
         Self {
             extras,
             requirements,

crates/uv-workspace/src/pyproject_mut.rs

@@ -1169,9 +1169,11 @@ pub fn add_dependency(
 /// Update an existing requirement.
 fn update_requirement(old: &mut Requirement, new: &Requirement, has_source: bool) {
     // Add any new extras.
-    old.extras.extend(new.extras.iter().cloned());
-    old.extras.sort_unstable();
-    old.extras.dedup();
+    let mut extras = old.extras.to_vec();
+    extras.extend(new.extras.iter().cloned());
+    extras.sort_unstable();
+    extras.dedup();
+    old.extras = extras.into_boxed_slice();
 
     // Clear the requirement source if we are going to add to `tool.uv.sources`.
     if has_source {

crates/uv-workspace/src/workspace.rs

@@ -306,8 +306,8 @@ impl Workspace {
                 .with_given(member.root.to_string_lossy());
             Some(Requirement {
                 name: member.pyproject_toml.project.as_ref()?.name.clone(),
-                extras: vec![],
-                groups: vec![],
+                extras: Box::new([]),
+                groups: Box::new([]),
                 marker: MarkerTree::TRUE,
                 source: if member.pyproject_toml.is_package() {
                     RequirementSource::Directory {
@@ -362,8 +362,8 @@ impl Workspace {
 
             Some(Requirement {
                 name: member.pyproject_toml.project.as_ref()?.name.clone(),
-                extras: vec![],
-                groups,
+                extras: Box::new([]),
+                groups: groups.into_boxed_slice(),
                 marker: MarkerTree::TRUE,
                 source: if member.pyproject_toml.is_package() {
                     RequirementSource::Directory {

crates/uv/src/commands/project/add.rs

@@ -438,9 +438,11 @@ pub(crate) async fn add(
     let mut edits = Vec::<DependencyEdit>::with_capacity(requirements.len());
     for mut requirement in requirements {
         // Add the specified extras.
-        requirement.extras.extend(extras.iter().cloned());
-        requirement.extras.sort_unstable();
-        requirement.extras.dedup();
+        let mut ex = requirement.extras.to_vec();
+        ex.extend(extras.iter().cloned());
+        ex.sort_unstable();
+        ex.dedup();
+        requirement.extras = ex.into_boxed_slice();
 
         let (requirement, source) = match target {
             AddTarget::Script(_, _) | AddTarget::Project(_, _) if raw_sources => {

crates/uv/src/commands/tool/install.rs

@@ -167,7 +167,7 @@ pub(crate) async fn install(
             Requirement {
                 name: name.clone(),
                 extras: extras.clone(),
-                groups: vec![],
+                groups: Box::new([]),
                 marker: MarkerTree::default(),
                 source: RequirementSource::Registry {
                     specifier: VersionSpecifiers::from(VersionSpecifier::equals_version(
@@ -188,7 +188,7 @@ pub(crate) async fn install(
             Requirement {
                 name: name.clone(),
                 extras: extras.clone(),
-                groups: vec![],
+                groups: Box::new([]),
                 marker: MarkerTree::default(),
                 source: RequirementSource::Registry {
                     specifier: VersionSpecifiers::empty(),