⚡ Bolt: Offload blocking I/O to background tasks to prevent UI freezes

.jules/bolt.md

@@ -0,0 +1,3 @@
+## 2024-06-18 - Offload Synchronous Operations from Main Actor
+**Learning:** In Swift Concurrency, `Task { ... }` created from within a `@MainActor` inherits that actor's context. To prevent synchronous, blocking operations (like `DiskInfo.current()`, `process.waitUntilExit()`, and `pipe.readDataToEndOfFile()`) from blocking the main thread and freezing the UI, they must be executed outside the actor's context.
+**Action:** Use `Task.detached { ... }` which does not inherit the actor context, and `await` its `.value` property to safely return the result without blocking the `@MainActor`.

Sources/Cacheout/ViewModels/CacheoutViewModel.swift

@@ -147,7 +147,8 @@ class CacheoutViewModel: ObservableObject {
     func scan() async {
         isScanning = true
         isNodeModulesScanning = true
-        diskInfo = DiskInfo.current()
+        // ⚡ Bolt: Offload blocking I/O to background thread to prevent UI freeze during scan startup
+        diskInfo = await Task.detached { DiskInfo.current() }.value
 
         // Scan caches and node_modules in parallel
         async let cacheResults = scanner.scanAll(CacheCategory.allCategories)
@@ -241,10 +242,13 @@ class CacheoutViewModel: ObservableObject {
         ]
 
         do {
-            try process.run()
-            process.waitUntilExit()
-            let data = pipe.fileHandleForReading.readDataToEndOfFile()
-            let output = String(data: data, encoding: .utf8) ?? ""
+            // ⚡ Bolt: Offload synchronous process execution to prevent MainActor blocking (~3-5s UI freeze prevention)
+            let output = try await Task.detached {
+                try process.run()
+                process.waitUntilExit()
+                let data = pipe.fileHandleForReading.readDataToEndOfFile()
+                return String(data: data, encoding: .utf8) ?? ""
+            }.value
 
             if process.terminationStatus == 0 {
                 // Extract "Total reclaimed space:" line
@@ -270,7 +274,8 @@ class CacheoutViewModel: ObservableObject {
         }
 
         // Refresh disk info after prune
-        diskInfo = DiskInfo.current()
+        // ⚡ Bolt: Offload blocking I/O to background thread to prevent UI freeze
+        diskInfo = await Task.detached { DiskInfo.current() }.value
     }
 
     func clean() async {