From 2f72f930d546c93fdf123a1e9d99ba72d1445665 Mon Sep 17 00:00:00 2001
From: "google-labs-jules[bot]"
 <161369871+google-labs-jules[bot]@users.noreply.github.com>
Date: Mon, 4 May 2026 05:34:52 +0000
Subject: [PATCH] =?UTF-8?q?=E2=9A=A1=20Bolt:=20parallelize=20NodeModulesSc?=
 =?UTF-8?q?anner?=
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Content-Type: text/plain; charset=UTF-8
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Marked `findNodeModules` and `directorySize` as `nonisolated` to allow `TaskGroup` subtasks to run in parallel on the global thread pool instead of being serialized on the actor. Combined separate `fileExists` and `attributesOfItem` calls into a single `URL.resourceValues` call. Passed `FileManager` as an argument to maintain dependency injection.

Co-authored-by: acebytes <2820910+acebytes@users.noreply.github.com>
---
 .jules/bolt.md                                   |  3 +++
 .../Cacheout/Scanner/NodeModulesScanner.swift    | 16 ++++++++--------
 2 files changed, 11 insertions(+), 8 deletions(-)
 create mode 100644 .jules/bolt.md

diff --git a/.jules/bolt.md b/.jules/bolt.md
new file mode 100644
index 0000000..7cbf3eb
--- /dev/null
+++ b/.jules/bolt.md
@@ -0,0 +1,3 @@
+## 2026-05-04 - Fix Actor Serialization in TaskGroup
+**Learning:** When an actor creates a `TaskGroup` and its subtasks call an `isolated` method on the same actor, execution is silently serialized on the actor's executor, destroying intended parallelism. Additionally, separate `FileManager.fileExists` and `attributesOfItem` calls create redundant syscalls.
+**Action:** Mark computationally intensive or state-independent methods as `nonisolated` so they run on the global concurrent pool. Use `URL.resourceValues(forKeys:)` for combined file existence and attribute checking in a single syscall.
diff --git a/Sources/Cacheout/Scanner/NodeModulesScanner.swift b/Sources/Cacheout/Scanner/NodeModulesScanner.swift
index 3ed4d8c..ac28a77 100644
--- a/Sources/Cacheout/Scanner/NodeModulesScanner.swift
+++ b/Sources/Cacheout/Scanner/NodeModulesScanner.swift
@@ -62,7 +62,7 @@ actor NodeModulesScanner {
                 let rootURL = home.appendingPathComponent(root)
                 guard fileManager.fileExists(atPath: rootURL.path) else { continue }
                 group.addTask {
-                    await self.findNodeModules(in: rootURL, maxDepth: maxDepth)
+                    await self.findNodeModules(in: rootURL, fileManager: self.fileManager, maxDepth: maxDepth)
                 }
             }
             for await items in group {
@@ -77,18 +77,18 @@ actor NodeModulesScanner {
             .sorted { $0.sizeBytes > $1.sizeBytes }
     }
 
-    private func findNodeModules(in directory: URL, maxDepth: Int, currentDepth: Int = 0) async -> [NodeModulesItem] {
+    nonisolated private func findNodeModules(in directory: URL, fileManager: FileManager, maxDepth: Int, currentDepth: Int = 0) async -> [NodeModulesItem] {
         guard currentDepth < maxDepth else { return [] }
 
         var results: [NodeModulesItem] = []
         let nodeModulesURL = directory.appendingPathComponent("node_modules")
 
         // Check if this directory contains node_modules
-        var isDir: ObjCBool = false
-        if fileManager.fileExists(atPath: nodeModulesURL.path, isDirectory: &isDir), isDir.boolValue {
-            let size = directorySize(at: nodeModulesURL)
+        if let values = try? nodeModulesURL.resourceValues(forKeys: [.isDirectoryKey, .contentModificationDateKey]),
+           values.isDirectory == true {
+            let size = directorySize(at: nodeModulesURL, fileManager: fileManager)
             if size > 0 {
-                let lastMod = try? fileManager.attributesOfItem(atPath: nodeModulesURL.path)[.modificationDate] as? Date
+                let lastMod = values.contentModificationDate
                 let projectName = directory.lastPathComponent
                 results.append(NodeModulesItem(
                     projectName: projectName,
@@ -113,14 +113,14 @@ actor NodeModulesScanner {
             let name = item.lastPathComponent
             guard !Self.skipDirs.contains(name) else { continue }
             guard (try? item.resourceValues(forKeys: [.isDirectoryKey]).isDirectory) == true else { continue }
-            let subResults = await findNodeModules(in: item, maxDepth: maxDepth, currentDepth: currentDepth + 1)
+            let subResults = await findNodeModules(in: item, fileManager: fileManager, maxDepth: maxDepth, currentDepth: currentDepth + 1)
             results.append(contentsOf: subResults)
         }
 
         return results
     }
 
-    private func directorySize(at url: URL) -> Int64 {
+    nonisolated private func directorySize(at url: URL, fileManager: FileManager) -> Int64 {
         var total: Int64 = 0
         guard let enumerator = fileManager.enumerator(
             at: url,