Check the CloudKit schema when packaging and show broken iCloud sync

mac/Sources/Byre/Startup.swift

@@ -1,3 +1,5 @@
+import ByreAPI
+import CloudKit
 import CoreData
 import Foundation
 import Observation
@@ -11,6 +13,7 @@ final class Servers {
 
     private(set) var entries: [(origin: String, record: ServerRecord)] = []
     private(set) var connections: [String: Connection] = [:]
+    private var syncs: [NSPersistentCloudKitContainer.EventType: ClientSync] = [:]
     var current: String?
     @ObservationIgnored var openWindow: (() -> Void)?
 
@@ -19,7 +22,11 @@ final class Servers {
         current = origins.first
         Task {
             for await note in NotificationCenter.default.notifications(named: NSPersistentCloudKitContainer.eventChangedNotification) {
-                if let event = note.userInfo?[NSPersistentCloudKitContainer.eventNotificationUserInfoKey] as? NSPersistentCloudKitContainer.Event, event.type == .import, event.endDate != nil {
+                guard let event = note.userInfo?[NSPersistentCloudKitContainer.eventNotificationUserInfoKey] as? NSPersistentCloudKitContainer.Event, let end = event.endDate else {
+                    continue
+                }
+                synced(event, end)
+                if event.type == .import {
                     for connection in connections.values {
                         connection.store?.drafts?.reload()
                     }
@@ -29,6 +36,26 @@ final class Servers {
         }
     }
 
+    private func synced(_ event: NSPersistentCloudKitContainer.Event, _ end: Date) {
+        let error = event.succeeded ? nil : syncError(event.error)
+        if let error {
+            log.error("icloud \(String(describing: event.type), privacy: .public) failed: \(error, privacy: .public)")
+        }
+        syncs[event.type] = ClientSync(ok: event.succeeded, error: error, at: end)
+        guard let sync else {
+            return
+        }
+        for connection in connections.values {
+            connection.store?.reportSync(sync)
+        }
+    }
+
+    // A failed export stays the state until an export succeeds, whatever imports do meanwhile.
+    var sync: ClientSync? {
+        let failed = syncs.values.filter { !$0.ok }
+        return (failed.isEmpty ? Array(syncs.values) : failed).max { $0.at < $1.at }
+    }
+
     var origins: [String] {
         entries.map(\.origin)
     }
@@ -103,6 +130,17 @@ final class Servers {
     }
 }
 
+private func syncError(_ error: (any Error)?) -> String {
+    guard let error else {
+        return "failed with no error"
+    }
+    let ns = error as NSError
+    if let partial = ns.userInfo[CKPartialErrorsByItemIDKey] as? [AnyHashable: any Error], let first = partial.values.first {
+        return "\(first.localizedDescription) (\(partial.count) records)"
+    }
+    return "\(ns.localizedDescription) (\(ns.domain) \(ns.code))"
+}
+
 func serverName(_ origin: String) -> String {
     let host = URL(string: origin)?.host() ?? origin
     return host.split(separator: ".").first.map(String.init) ?? host