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, 8 insertions, 6 deletions

diff --git a/crates/shirabe/src/command/update_command.rs b/crates/shirabe/src/command/update_command.rs
index 0548fc02..09809eb2 100644
--- a/crates/shirabe/src/command/update_command.rs
+++ b/crates/shirabe/src/command/update_command.rs
@@ -83,8 +83,8 @@ impl UpdateCommand {
         let platform_req_filter = self.get_platform_requirement_filter(input);
         let stability_flags = composer_ref.get_package().get_stability_flags();
         let requires = array_merge_map(
-            composer_ref.get_package().get_requires(),
-            composer_ref.get_package().get_dev_requires(),
+            (*composer_ref.get_package().get_requires()).clone(),
+            (*composer_ref.get_package().get_dev_requires()).clone(),
         );
 
         let filter: Option<String> = if !packages.is_empty() {
@@ -156,7 +156,7 @@ impl UpdateCommand {
             }
         }
         if installed_packages.is_empty() {
-            for (req, _constraint) in &requires {
+            for (req, _constraint) in requires.iter() {
                 if PlatformRepository::is_platform_package(req) {
                     continue;
                 }
@@ -401,9 +401,11 @@ impl Command for UpdateCommand {
 
         let parser = VersionParser::new();
         let mut temporary_constraints: IndexMap<String, _> = IndexMap::new();
-        let root_requirements =
-            array_merge_map(root_package.get_requires(), root_package.get_dev_requires());
-        for (package, constraint) in &reqs {
+        let root_requirements = array_merge_map(
+            (*root_package.get_requires()).clone(),
+            (*root_package.get_dev_requires()).clone(),
+        );
+        for (package, constraint) in reqs.iter() {
             let package = strtolower(package);
             let parsed_constraint = parser.parse_constraints(constraint)?;
             temporary_constraints.insert(package.clone(), parsed_constraint.clone());