1 files changed, 18 insertions, 3 deletions
diff --git a/crates/shirabe/src/repository/version_cache_interface.rs b/crates/shirabe/src/repository/version_cache_interface.rs
index 6dfeec0..65e5195 100644
--- a/crates/shirabe/src/repository/version_cache_interface.rs
+++ b/crates/shirabe/src/repository/version_cache_interface.rs
@@ -1,7 +1,22 @@
 //! ref: composer/src/Composer/Repository/VersionCacheInterface.php
 
+use indexmap::IndexMap;
+use shirabe_php_shim::PhpMixed;
+
+/// Result of looking up a cached package version.
+///
+/// PHP's `getVersionPackage(...)` returns either an array (the package data),
+/// `null` (cache miss), or `false` (cached absence). We model that as an enum.
+#[derive(Debug)]
+pub enum VersionCacheResult {
+    /// Cache miss (PHP `null`).
+    None,
+    /// Cached absence (PHP `false`).
+    Missing,
+    /// Cached package data (PHP `array`).
+    Package(IndexMap<String, PhpMixed>),
+}
+
 pub trait VersionCacheInterface: std::fmt::Debug {
-    // No class implementing this interface exists in Composer's codebase; a plugin may provide
-    // one, but plugin support is not yet decided. Using () as a placeholder until then.
-    fn get_version_package(&self, version: &str, identifier: &str) -> ();
+    fn get_version_package(&self, version: &str, identifier: &str) -> VersionCacheResult;
 }