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, 2 deletions

diff --git a/crates/shirabe/src/command/remove_command.rs b/crates/shirabe/src/command/remove_command.rs
index 9004a9fd..e50999bb 100644
--- a/crates/shirabe/src/command/remove_command.rs
+++ b/crates/shirabe/src/command/remove_command.rs
@@ -479,8 +479,14 @@ impl Command for RemoveCommand {
         if dry_run {
             let root_package = composer.get_package();
             let mut links: IndexMap<String, IndexMap<String, _>> = IndexMap::new();
-            links.insert("require".to_string(), root_package.get_requires());
-            links.insert("require-dev".to_string(), root_package.get_dev_requires());
+            links.insert(
+                "require".to_string(),
+                (*root_package.get_requires()).clone(),
+            );
+            links.insert(
+                "require-dev".to_string(),
+                (*root_package.get_dev_requires()).clone(),
+            );
             for (link_type, names) in &to_remove {
                 for name in names {
                     if let Some(section) = links.get_mut(link_type.as_str()) {