perf(plugins): reuse persisted registry fallback read

src/plugins/plugin-registry.test.ts

@@ -309,6 +309,13 @@ describe("plugin registry facade", () => {
         policyHash: resolveInstalledPluginIndexPolicyHash({
           plugins: { entries: { persisted: { enabled: true } } },
         }),
+        installRecords: {
+          persisted: {
+            source: "npm",
+            spec: "persisted-plugin@1.0.0",
+            installPath: path.join(stateDir, "plugins", "persisted"),
+          },
+        },
       }),
       { stateDir },
     );
@@ -329,6 +336,12 @@ describe("plugin registry facade", () => {
     expect(listPluginRecords({ index: result.snapshot }).map((plugin) => plugin.pluginId)).toEqual([
       "demo",
     ]);
+    expect(result.snapshot.installRecords).toMatchObject({
+      persisted: {
+        source: "npm",
+        spec: "persisted-plugin@1.0.0",
+      },
+    });
   });
 
   it("falls back to the derived registry when the persisted registry is missing", () => {

src/plugins/plugin-registry.ts

@@ -326,12 +326,13 @@ export function loadPluginRegistrySnapshotWithMetadata(
   const disabledByCaller = params.preferPersisted === false;
   const disabledByEnv = hasEnvFlag(env, DISABLE_PERSISTED_PLUGIN_REGISTRY_ENV);
   const persistedReadsEnabled = !disabledByCaller && !disabledByEnv;
+  let persistedIndex: InstalledPluginIndex | null = null;
   if (persistedReadsEnabled) {
-    const persisted = readPersistedInstalledPluginIndexSync(params);
-    if (persisted) {
+    persistedIndex = readPersistedInstalledPluginIndexSync(params);
+    if (persistedIndex) {
       if (
         params.config &&
-        persisted.policyHash !== resolveInstalledPluginIndexPolicyHash(params.config)
+        persistedIndex.policyHash !== resolveInstalledPluginIndexPolicyHash(params.config)
       ) {
         diagnostics.push({
           level: "warn",
@@ -341,7 +342,7 @@ export function loadPluginRegistrySnapshotWithMetadata(
         });
       } else {
         return {
-          snapshot: persisted,
+          snapshot: persistedIndex,
           source: "persisted",
           diagnostics,
         };
@@ -368,9 +369,7 @@ export function loadPluginRegistrySnapshotWithMetadata(
       ...params,
       installRecords:
         params.installRecords ??
-        extractPluginInstallRecordsFromInstalledPluginIndex(
-          persistedReadsEnabled ? readPersistedInstalledPluginIndexSync(params) : null,
-        ),
+        extractPluginInstallRecordsFromInstalledPluginIndex(persistedIndex),
     }),
     source: "derived",
     diagnostics,