From de09f66e96600989303b7f7120193aa87d68c999 Mon Sep 17 00:00:00 2001
From: "google-labs-jules[bot]"
 <161369871+google-labs-jules[bot]@users.noreply.github.com>
Date: Tue, 5 May 2026 05:21:37 +0000
Subject: [PATCH] =?UTF-8?q?=E2=9A=A1=20Bolt:=20Make=20NodeModulesScanner?=
 =?UTF-8?q?=20truly=20concurrent=20and=20reduce=20syscalls?=
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Co-authored-by: acebytes <2820910+acebytes@users.noreply.github.com>
---
 .jules/bolt.md                                |  3 +++
 .../Cacheout/Scanner/NodeModulesScanner.swift | 21 +++++++++----------
 2 files changed, 13 insertions(+), 11 deletions(-)
 create mode 100644 .jules/bolt.md

diff --git a/.jules/bolt.md b/.jules/bolt.md
new file mode 100644
index 0000000..e8bc0d5
--- /dev/null
+++ b/.jules/bolt.md
@@ -0,0 +1,3 @@
+## 2024-05-05 - TaskGroup parallelism and URL.resourceValues
+**Learning:** In Swift Concurrency, when an actor creates a `TaskGroup` and its subtasks call an `isolated` method on the same actor, execution is serialized on the actor's executor, destroying parallelism. Also, `URL.resourceValues(forKeys:)` can perform a single optimized syscall instead of separate `FileManager.fileExists` and `FileManager.attributesOfItem` calls.
+**Action:** Mark computationally intensive or state-independent methods as `static` or `nonisolated` so they run on the global concurrent pool, and pass dependencies (like `FileManager` and `skipDirs`) as arguments. Use `URL.resourceValues(forKeys:)` for checking directory existence and attributes simultaneously.
diff --git a/Sources/Cacheout/Scanner/NodeModulesScanner.swift b/Sources/Cacheout/Scanner/NodeModulesScanner.swift
index 3ed4d8c..70dbd47 100644
--- a/Sources/Cacheout/Scanner/NodeModulesScanner.swift
+++ b/Sources/Cacheout/Scanner/NodeModulesScanner.swift
@@ -55,14 +55,15 @@ actor NodeModulesScanner {
     func scan(maxDepth: Int = 6) async -> [NodeModulesItem] {
         let home = fileManager.homeDirectoryForCurrentUser
         var allItems: [NodeModulesItem] = []
+        let currentFileManager = self.fileManager
 
         // Scan each search root in parallel
         await withTaskGroup(of: [NodeModulesItem].self) { group in
             for root in Self.searchRoots {
                 let rootURL = home.appendingPathComponent(root)
-                guard fileManager.fileExists(atPath: rootURL.path) else { continue }
+                guard currentFileManager.fileExists(atPath: rootURL.path) else { continue }
                 group.addTask {
-                    await self.findNodeModules(in: rootURL, maxDepth: maxDepth)
+                    await Self.findNodeModules(in: rootURL, fileManager: currentFileManager, skipDirs: Self.skipDirs, maxDepth: maxDepth)
                 }
             }
             for await items in group {
@@ -77,25 +78,23 @@ actor NodeModulesScanner {
             .sorted { $0.sizeBytes > $1.sizeBytes }
     }
 
-    private func findNodeModules(in directory: URL, maxDepth: Int, currentDepth: Int = 0) async -> [NodeModulesItem] {
+    private static func findNodeModules(in directory: URL, fileManager: FileManager, skipDirs: Set<String>, 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 projectName = directory.lastPathComponent
                 results.append(NodeModulesItem(
                     projectName: projectName,
                     projectPath: directory,
                     nodeModulesPath: nodeModulesURL,
                     sizeBytes: size,
-                    lastModified: lastMod
+                    lastModified: values.contentModificationDate
                 ))
             }
             // Don't recurse into projects that have node_modules — they won't have nested projects
@@ -111,16 +110,16 @@ actor NodeModulesScanner {
 
         for item in contents {
             let name = item.lastPathComponent
-            guard !Self.skipDirs.contains(name) else { continue }
+            guard !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, skipDirs: skipDirs, maxDepth: maxDepth, currentDepth: currentDepth + 1)
             results.append(contentsOf: subResults)
         }
 
         return results
     }
 
-    private func directorySize(at url: URL) -> Int64 {
+    private static func directorySize(at url: URL, fileManager: FileManager) -> Int64 {
         var total: Int64 = 0
         guard let enumerator = fileManager.enumerator(
             at: url,