refactor: Update IndexPackage to use Cow for features

Signed-off-by: 0xPoe <techregister@pm.me>

Author: 0xPoe

src/cargo/sources/registry/index/mod.rs

@@ -207,14 +207,14 @@ pub struct IndexPackage<'a> {
     pub deps: Vec<RegistryDependency<'a>>,
     /// Set of features defined for the package, i.e., `[features]` table.
     #[serde(default)]
-    pub features: BTreeMap<InternedString, Vec<InternedString>>,
+    pub features: BTreeMap<Cow<'a, str>, Vec<Cow<'a, str>>>,
     /// This field contains features with new, extended syntax. Specifically,
     /// namespaced features (`dep:`) and weak dependencies (`pkg?/feat`).
     ///
     /// This is separated from `features` because versions older than 1.19
     /// will fail to load due to not being able to parse the new syntax, even
     /// with a `Cargo.lock` file.
-    pub features2: Option<BTreeMap<InternedString, Vec<InternedString>>>,
+    pub features2: Option<BTreeMap<Cow<'a, str>, Vec<Cow<'a, str>>>>,
     /// Checksum for verifying the integrity of the corresponding downloaded package.
     pub cksum: String,
     /// If `true`, Cargo will skip this version when resolving.
@@ -276,9 +276,21 @@ impl IndexPackage<'_> {
         let mut features = self.features.clone();
         if let Some(features2) = &self.features2 {
             for (name, values) in features2 {
-                features.entry(*name).or_default().extend(values);
+                features
+                    .entry(name.clone())
+                    .or_default()
+                    .extend(values.iter().cloned());
             }
         }
+        let features = features
+            .into_iter()
+            .map(|(name, values)| {
+                (
+                    InternedString::new(&name),
+                    values.iter().map(|v| InternedString::new(&v)).collect(),
+                )
+            })
+            .collect::<BTreeMap<_, _>>();
         let mut summary = Summary::new(
             pkgid,
             deps,