fix(update): preserve locked refs and aliases on partial update

Partial update of a non-allow-listed dev package now resolves and emits
the locked-repo entry verbatim, mirroring Composer's `PoolBuilder`.
Three coordinated changes:

- resolver: `lock_filter_allows` accepts the locked package's branch-
  alias normalized versions, not just the base. Without this, root
  constraints like `~2.1` against a `dev-master` locked package whose
  branch alias is `2.1.x-dev` failed with "no matching package found".
- lockfile: new `lock_pinned_names` field on `LockFileGenerationRequest`
  routes non-allow-listed packages through `previous_lock_lookup`
  before `inline_lookup`, so the lock's source/dist references survive
  even when the inline metadata has moved to a newer commit.
- update: `apply_partial_update` skips alias entries — re-pinning their
  pretty `version` to the base would collapse the alias label and
  emit a self-referential entry in the new lock's `aliases[]` block.

Unblocks partial_update_forces_dev_reference_from_lock_for_non_updated_packages.

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

2 files changed, 52 insertions, 5 deletions

diff --git a/crates/mozart-registry/src/lockfile.rs b/crates/mozart-registry/src/lockfile.rs
index 94983e3..5a293fe 100644
--- a/crates/mozart-registry/src/lockfile.rs
+++ b/crates/mozart-registry/src/lockfile.rs
@@ -467,6 +467,16 @@ pub struct LockFileGenerationRequest {
     /// during partial updates: lock entries are stable across updates that
     /// don't touch the package, even if the upstream metadata has drifted.
     pub previous_lock: Option<LockFile>,
+    /// Lowercase package names that were held back to their locked version
+    /// on a partial update — i.e. they were NOT in the CLI's allow list and
+    /// were re-pinned by `apply_partial_update`. For these names the lock
+    /// entry's metadata (source/dist references in particular) is canonical:
+    /// inline / composer-repo metadata may have drifted to a newer commit
+    /// that the partial update is explicitly choosing not to take. Mirrors
+    /// Composer's `PoolBuilder`, which keeps non-allow-listed packages at
+    /// the locked-repo entry rather than re-loading them from the inline /
+    /// VCS sources.
+    pub lock_pinned_names: indexmap::IndexSet<String>,
 }
 
 impl LockFileGenerationRequest {
@@ -926,6 +936,21 @@ pub async fn generate_lock_file(request: &LockFileGenerationRequest) -> anyhow::
     let mut package_metadata: IndexMap<String, PackagistVersion> = IndexMap::new();
     let repo_set = &request.repositories;
     for pkg in &real_resolved {
+        // For packages held back to the locked version on a partial update,
+        // the lock entry is the canonical metadata source. Inline / composer-
+        // repo / VCS sources may have moved to a newer commit that this
+        // partial update is explicitly choosing NOT to take, so consulting
+        // them first would silently bump the source/dist reference. Mirrors
+        // Composer's `PoolBuilder` behaviour: non-allow-listed packages keep
+        // the locked-repo entry rather than re-loading from upstream.
+        let pinned = request.lock_pinned_names.contains(&pkg.name.to_lowercase());
+        if pinned
+            && let Some(prev) = request.previous_lock_lookup(&pkg.name, &pkg.version_normalized)
+        {
+            package_metadata.insert(pkg.name.clone(), prev);
+            continue;
+        }
+
         if let Some(inline) = request.inline_lookup(&pkg.name, &pkg.version_normalized) {
             package_metadata.insert(pkg.name.clone(), inline);
             continue;
@@ -1640,6 +1665,7 @@ mod tests {
                 crate::cache::Cache::new(std::env::temp_dir().join("mozart-test-cache"), false),
             )),
             previous_lock: None,
+            lock_pinned_names: IndexSet::new(),
         };
 
         let lock = generate_lock_file(&request).await.unwrap();
@@ -1787,6 +1813,7 @@ mod tests {
                 false,
             ))),
             previous_lock: None,
+            lock_pinned_names: IndexSet::new(),
         };
 
         let lock = generate_lock_file(&gen_request)
diff --git a/crates/mozart-registry/src/resolver.rs b/crates/mozart-registry/src/resolver.rs
index c592e01..35856c3 100644
--- a/crates/mozart-registry/src/resolver.rs
+++ b/crates/mozart-registry/src/resolver.rs
@@ -800,6 +800,13 @@ pub struct LockedPackageInfo {
     pub replaces: Vec<(String, String)>,
     pub provides: Vec<(String, String)>,
     pub conflicts: Vec<(String, String)>,
+    /// Branch-alias entries to surface alongside the base locked package, as
+    /// `(pretty, normalized)` pairs. Mirrors what
+    /// `Composer\Package\Locker::getLockedRepository` constructs from
+    /// `extra.branch-alias`: a `dev-master` locked package with branch alias
+    /// `2.1.x-dev` needs to expose itself under both versions so root
+    /// constraints like `~2.1` still resolve on a partial update.
+    pub branch_aliases: Vec<(String, String)>,
 }
 
 /// A single package in the resolution output.
@@ -1098,15 +1105,28 @@ pub async fn resolve(request: &ResolveRequest) -> Result<Vec<ResolvedPackage>, R
     }
 
     // Build a map first so the filter below knows which (name, version)
-    // pairs are the only allowed entries for locked names.
-    let locked_name_to_version: IndexMap<String, String> = request
+    // pairs are the only allowed entries for locked names. Each entry holds
+    // the locked normalized version plus any branch-alias normalized
+    // versions Composer's `Locker::getLockedRepository` would expose
+    // alongside the base. Without the alias entries, an inline-package or
+    // VCS source providing the same `dev-master` + alias as the lock would
+    // have its alias filtered out, leaving root constraints like `~2.1` —
+    // which can only match the alias version, not the raw `dev-master` —
+    // unsatisfiable on a partial update.
+    let locked_name_to_versions: IndexMap<String, Vec<String>> = request
         .locked_packages
         .iter()
-        .map(|p| (p.name.to_lowercase(), p.version_normalized.clone()))
+        .map(|p| {
+            let mut versions = vec![p.version_normalized.clone()];
+            for (_, alias_normalized) in &p.branch_aliases {
+                versions.push(alias_normalized.clone());
+            }
+            (p.name.to_lowercase(), versions)
+        })
         .collect();
     let lock_filter_allows = |name: &str, version: &str| -> bool {
-        match locked_name_to_version.get(&name.to_lowercase()) {
-            Some(locked_version) => locked_version == version,
+        match locked_name_to_versions.get(&name.to_lowercase()) {
+            Some(locked_versions) => locked_versions.iter().any(|v| v == version),
             None => true,
         }
     };