perf(package): hand out link maps behind Rc

PackageInterface::getRequires() and friends return the array of Link objects;
in PHP that is a copy-on-write array of object references, so a caller pays
nothing to look at it. The port returned IndexMap<String, Link> by value, so
every call deep-cloned the whole map, keys and constraints included. Pool
building calls these accessors once per package per candidate, which put
IndexMap::clone at 13.5% of `require laravel/laravel`.

Store the maps as Rc<IndexMap<String, Link>> and return a handle. Callers that
mutate the map clone it explicitly at the point of mutation, matching where PHP
would separate the array.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

1 files changed, 7 insertions, 2 deletions

diff --git a/crates/shirabe/src/repository/repository_utils.rs b/crates/shirabe/src/repository/repository_utils.rs
index c2997f31..3df86b05 100644
--- a/crates/shirabe/src/repository/repository_utils.rs
+++ b/crates/shirabe/src/repository/repository_utils.rs
@@ -16,9 +16,14 @@ impl RepositoryUtils {
         include_require_dev: bool,
         mut bucket: Vec<crate::package::BasePackageHandle>,
     ) -> Vec<crate::package::BasePackageHandle> {
-        let mut requires: IndexMap<String, Link> = requirer.get_requires();
+        let mut requires: IndexMap<String, Link> = (*requirer.get_requires()).clone();
         if include_require_dev {
-            requires.extend(requirer.get_dev_requires());
+            requires.extend(
+                requirer
+                    .get_dev_requires()
+                    .iter()
+                    .map(|(k, v)| (k.clone(), v.clone())),
+            );
         }
 
         for candidate in packages {