SwiftUI：在Commands菜单中使用fileImporter致macOS应用崩溃

我发现一个特殊现象：带有打开fileImporter按钮的视图，在普通视图中可正常运行，但将其放入Commands菜单后，macOS应用会直接崩溃。请问有人知道原因吗？

注：仅开发macOS应用。

相关代码 #

FileImporter按钮视图代码 #

import SwiftUI

struct FileImporterButtonView: View {
   @State var isPresented = false

   var body: some View {
      Button("Open...") {
         isPresented.toggle()
      }
      .keyboardShortcut("O")
      .fileImporter(isPresented: $isPresented, allowedContentTypes: [.item], allowsMultipleSelection: false, onCompletion: { _ in
         print("just tried to open file importer...")
      })
   }
}

ContentView代码 #

import SwiftUI

struct ContentView: View {
   var body: some View {
      FileImporterButtonView() // File importer works fine
   }
}

应用入口代码 #

import SwiftUI

@main
struct fileImporterCrashApp: App {
    var body: some Scene {
        WindowGroup {
            ContentView()
        }.commands {
           CommandGroup(before: CommandGroupPlacement.newItem) {
              FileImporterButtonView() // This leads to crash, why???
           }
        }
    }
}

崩溃信息 #

崩溃截图 #

崩溃栈信息 #

SwiftUI`___lldb_unnamed_symbol194403:
0x1b3f45dec <+0>:   pacibsp 
0x1b3f45df0 <+4>:   stp    x22, x21, [sp, #-0x30]!
0x1b3f45df4 <+8>:   stp    x20, x19, [sp, #0x10]
0x1b3f45df8 <+12>:  stp    x29, x30, [sp, #0x20]
0x1b3f45dfc <+16>:  add    x29, sp, #0x20
0x1b3f45e00 <+20>:  mov    x19, x8
0x1b3f45e04 <+24>:  adrp   x8, 180875
0x1b3f45e08 <+28>:  ldr    x8, [x8, #0x390]
0x1b3f45e0c <+32>:  add    x21, x20, x8
0x1b3f45e10 <+36>:  mov    x0, x21
0x1b3f45e14 <+40>:  bl     0x1b4786850               ; symbol stub for: swift_unknownObjectWeakLoadStrong
0x1b3f45e18 <+44>:  cbz    x0, 0x1b3f45e7c           ; <+144>
0x1b3f45e1c <+48>:  mov    x20, x0
0x1b3f45e20 <+52>:  ldr    x21, [x21, #0x8]
0x1b3f45e24 <+56>:  bl     0x1b4786470               ; symbol stub for: swift_getObjectType
0x1b3f45e28 <+60>:  mov    x8, x21
0x1b3f45e2c <+64>:  ldr    x9, [x8, #0x10]!
0x1b3f45e30 <+68>:  mov    x1, x21
0x1b3f45e34 <+72>:  mov    x17, x8
0x1b3f45e38 <+76>:  movk   x17, #0x6cba, lsl #48
0x1b3f45e3c <+80>:  blraa  x9, x17
0x1b3f45e40 <+84>:  mov    x21, x0
0x1b3f45e44 <+88>:  mov    x0, x20
0x1b3f45e48 <+92>:  bl     0x1b4785e50               ; symbol stub for: objc_release
0x1b3f45e4c <+96>:  mov    x8, x19
0x1b3f45e50 <+100>: mov    x20, x21
0x1b3f45e54 <+104>: bl     0x1b43e1774               ; ___lldb_unnamed_symbol225352
0x1b3f45e58 <+108>: mov    x0, x21
0x1b3f45e5c <+112>: ldp    x29, x30, [sp, #0x20]
0x1b3f45e60 <+116>: ldp    x20, x19, [sp, #0x10]
0x1b3f45e64 <+120>: ldp    x22, x21, [sp], #0x30
0x1b3f45e68 <+124>: autibsp 
0x1b3f45e6c <+128>: eor    x16, x30, x30, lsl #1
0x1b3f45e70 <+132>: tbz    x16, #0x3e, 0x1b3f45e78   ; <+140>
0x1b3f45e74 <+136>: brk    #0xc471
0x1b3f45e78 <+140>: b      0x1b4786630               ; symbol stub for: swift_release
->  0x1b3f45e7c <+144>: brk    #0x1

原因分析 #

Commands菜单属于应用的全局命令层结构，和普通窗口内容视图的生命周期、上下文环境完全不同：

1. fileImporter修饰符依赖当前视图所在的**窗口场景（WindowScene）**提供文件选择器的展示上下文，但Commands菜单不隶属于任何具体窗口场景，导致找不到有效上下文触发空指针崩溃。
2. @State变量在Commands菜单中的生命周期管理异常——Commands菜单视图是全局懒加载的，@State的状态逻辑无法正常工作，进一步加剧崩溃风险。

解决方法 #

不要直接在Commands菜单中使用带fileImporter的视图，而是通过全局状态触发+窗口视图响应的方式实现：

优化后的应用入口代码 #

import SwiftUI

// 定义全局应用状态
class AppState: ObservableObject {
    @Published var showFileImporter = false
}

@main
struct fileImporterCrashApp: App {
    @StateObject private var appState = AppState()
    
    var body: some Scene {
        WindowGroup {
            ContentView()
                .environmentObject(appState)
                // 将fileImporter放在有窗口场景的视图上
                .fileImporter(
                    isPresented: $appState.showFileImporter,
                    allowedContentTypes: [.item],
                    allowsMultipleSelection: false
                ) { result in
                    print("just tried to open file importer...")
                    // 处理文件选择结果
                }
        }.commands {
           CommandGroup(before: CommandGroupPlacement.newItem) {
              Button("Open...") {
                  // 仅触发全局状态
                  appState.showFileImporter = true
              }
              .keyboardShortcut("O")
           }
        }
    }
}

简化后的ContentView（可选） #

如果不需要在窗口内保留打开按钮，可以简化ContentView：

import SwiftUI

struct ContentView: View {
    var body: some View {
        Text("Hello, World!")
    }
}

这种方式将文件选择器的展示逻辑放在拥有有效窗口场景的视图中，Commands菜单仅负责触发状态，既避开了上下文缺失的问题，又保留了快捷键功能。

内容的提问来源于Stack Exchange，提问作者Kirill Rud