fix(registry): respect priority order across inline package repos

When a `type: package` repository declares a name already declared by a
higher-priority `type: package` entry, drop it. Mirrors Composer's
RepositorySet first-repo-wins semantics so duplicate names across inline
repositories cannot promote a lower-priority version into the pool.

Greens 4 installer fixtures: install_prefers_repos_over_package_versions,
repositories_priorities2, repositories_priorities4,
update_package_present_in_lower_repo_prio_but_not_main_due_to_min_stability.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

2 files changed, 24 insertions, 9 deletions

diff --git a/crates/mozart-registry/src/inline_package.rs b/crates/mozart-registry/src/inline_package.rs
index e10cd2b..bad00fb 100644
--- a/crates/mozart-registry/src/inline_package.rs
+++ b/crates/mozart-registry/src/inline_package.rs
@@ -7,6 +7,7 @@
 
 use crate::packagist::PackagistVersion;
 use mozart_core::package::RawRepository;
+use std::collections::HashSet;
 
 /// One package extracted from a `type: package` repository.
 pub struct InlinePackage {
@@ -20,8 +21,14 @@ pub struct InlinePackage {
 /// objects. Entries that fail to parse (missing `name`/`version`, etc.) are
 /// silently skipped so the rest of the repositories list still applies —
 /// matching Composer's lenient PackageRepository constructor.
+///
+/// Repositories are processed in declaration order. Once any repository
+/// authoritatively answers for a package name, lower-priority `type: package`
+/// repositories that list the same name are skipped — mirroring Composer's
+/// first-repo-wins priority via `RepositorySet::findPackages`.
 pub fn collect_inline_packages(repositories: &[RawRepository]) -> Vec<InlinePackage> {
     let mut packages = Vec::new();
+    let mut claimed: HashSet<String> = HashSet::new();
     for repo in repositories {
         if repo.repo_type != "package" {
             continue;
@@ -30,21 +37,32 @@ pub fn collect_inline_packages(repositories: &[RawRepository]) -> Vec<InlinePack
             continue;
         };
 
+        let mut from_this_repo: Vec<InlinePackage> = Vec::new();
         match value {
             serde_json::Value::Array(arr) => {
                 for entry in arr {
                     if let Some(pkg) = parse_inline_package(entry) {
-                        packages.push(pkg);
+                        from_this_repo.push(pkg);
                     }
                 }
             }
             serde_json::Value::Object(_) => {
                 if let Some(pkg) = parse_inline_package(value) {
-                    packages.push(pkg);
+                    from_this_repo.push(pkg);
                 }
             }
             _ => {}
         }
+
+        let mut names_this_repo: HashSet<String> = HashSet::new();
+        for pkg in from_this_repo {
+            if claimed.contains(&pkg.name) {
+                continue;
+            }
+            names_this_repo.insert(pkg.name.clone());
+            packages.push(pkg);
+        }
+        claimed.extend(names_this_repo);
     }
     packages
 }
diff --git a/crates/mozart/tests/installer.rs b/crates/mozart/tests/installer.rs
index 6c0291b..7ba53a8 100644
--- a/crates/mozart/tests/installer.rs
+++ b/crates/mozart/tests/installer.rs
@@ -275,7 +275,7 @@ installer_fixture!(install_ignore_platform_package_requirements);
 installer_fixture!(install_missing_alias_from_lock, ignore);
 installer_fixture!(install_overridden_platform_packages, ignore);
 installer_fixture!(install_package_and_its_provider_skips_original);
-installer_fixture!(install_prefers_repos_over_package_versions, ignore);
+installer_fixture!(install_prefers_repos_over_package_versions);
 installer_fixture!(install_reference);
 installer_fixture!(install_security_advisory_matching_dependency);
 installer_fixture!(install_self_from_root);
@@ -344,9 +344,9 @@ installer_fixture!(
 );
 installer_fixture!(replacer_satisfies_its_own_requirement);
 installer_fixture!(repositories_priorities, ignore);
-installer_fixture!(repositories_priorities2, ignore);
+installer_fixture!(repositories_priorities2);
 installer_fixture!(repositories_priorities3, ignore);
-installer_fixture!(repositories_priorities4, ignore);
+installer_fixture!(repositories_priorities4);
 installer_fixture!(repositories_priorities5, ignore);
 installer_fixture!(root_alias_change_with_circular_dep, ignore);
 installer_fixture!(root_alias_gets_loaded_for_locked_pkgs);
@@ -413,10 +413,7 @@ installer_fixture!(update_no_install);
 installer_fixture!(update_package_present_in_lock_but_not_at_all_in_remote);
 installer_fixture!(update_package_present_in_lock_but_not_in_remote);
 installer_fixture!(update_package_present_in_lock_but_not_in_remote_due_to_min_stability);
-installer_fixture!(
-    update_package_present_in_lower_repo_prio_but_not_main_due_to_min_stability,
-    ignore
-);
+installer_fixture!(update_package_present_in_lower_repo_prio_but_not_main_due_to_min_stability);
 installer_fixture!(update_picks_up_change_of_vcs_type, ignore);
 installer_fixture!(update_prefer_lowest_stable);
 installer_fixture!(update_reference, ignore);