iCloud Drive版本冲突：NSFileVersion修改日期异常导致无法判定最新版本

冲突触发场景 #

• 使用同一Apple账号绑定的两台设备（iPhone XR和iPad），按以下步骤触发文件冲突：
  1. 在在线设备（iPhone XR）上创建文本文件；
  2. 在离线设备（iPad）上编辑该文件；
  3. 再次在在线设备（iPhone XR）上更新文件内容；
  4. 将离线设备（iPad）切换回在线状态。

预期与实际问题 #

预期能获取iPhone XR上最后更新的文件内容，但读取时出现版本冲突。尝试遵循Apple官方文档建议，通过NSFileVersion对比修改日期解决冲突，却发现NSFileVersion.unresolvedConflictVersionsOfItem与NSFileVersion.currentVersionOfItem的modificationDate完全相同，无法准确判定最新版本。

使用的代码片段 #

private func pickLatestVersion(for documentURL: URL) -> Bool {
        guard let versionsInConflict = NSFileVersion.unresolvedConflictVersionsOfItem(at: documentURL),
              let currentVersion = NSFileVersion.currentVersionOfItem(at: documentURL) else {
            return false
        }
        let currentVersionURLDate: Date? = currentVersion.url.getAttribute(fileAttribute: .modificationDate)
        print("Current Version: ", currentVersion.modificationDate?.formatted(date: .abbreviated, time: .complete))
        print("Current Version URL DATE: ", currentVersionURLDate?.formatted(date: .abbreviated, time: .complete))
        let currentString = try? String(contentsOf: currentVersion.url, encoding: .utf8)
        print("Current String: ", currentString)
        var shouldRevert = false
        var winner = currentVersion
        for version in versionsInConflict {
            let versionURLDate: Date? = version.url.getAttribute(fileAttribute: .modificationDate)
            print("Conflict Version: ", version.modificationDate?.formatted(date: .abbreviated, time: .complete))
            print("Conflict Version URL DATE: ", versionURLDate?.formatted(date: .abbreviated, time: .complete))
            let conflictString = try? String(contentsOf: version.url, encoding: .utf8)
            print("Conflict String: ", conflictString)
            
            if let date1 = version.modificationDate, let date2 = currentVersion.modificationDate,
               date1 > date2 {
                winner = version
            }
        }
        if winner != currentVersion {
            do {
                try winner.replaceItem(at: documentURL)
                shouldRevert = true
            } catch {
                print("Failed to replace version: \(error)")
            }
        }
        do {
            try NSFileVersion.removeOtherVersionsOfItem(at: documentURL)
            versionsInConflict.forEach({$0.isResolved = true})
        } catch {
            print("Failed to remove other versions: \(error)")
        }
        return shouldRevert
    }

冲突日志 #

Conflicts exist for the document file located at the file URL. Current
Version:  Optional("Apr 15, 2024 at 5:18:21 PM GMT+3") Current Version
URL DATE:  Optional("Apr 15, 2024 at 5:18:21 PM GMT+3") Current
String:  Optional("Xr") Conflict Version:  Optional("Apr 15, 2024 at
5:18:21 PM GMT+3") Conflict Version URL DATE:  Optional("Apr 15, 2024
at 5:18:35 PM GMT+3") Conflict String:  Optional(“iPad one)

此外，还存在疑问：为何从冲突文件URL获取的modificationDate属性值与NSFileVersion.modificationDate返回值不一致？希望得到该问题的见解或解决方案，可通过完整Xcode项目复现问题。

内容的提问来源于stack exchange，提问作者KAMIKAZE