Limit synced channels count to 100 (#3863)

Author: laevandus

CHANGELOG.md

@@ -8,6 +8,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - Fix `ChannelController.hasLoadedAllPreviousMessages` not correct for newly created channels [#3855](https://github.com/GetStream/stream-chat-swift/pull/3855)
 - Fix duplicated watch channel requests when a channel is created and it belongs to multiple queries [#3857](https://github.com/GetStream/stream-chat-swift/pull/3857)
 - Fix calling watch channel request when a channel is updated and it already belongs to another query [#3857](https://github.com/GetStream/stream-chat-swift/pull/3857)
+- Fix syncing error when trying to sync too many channels [#3863](https://github.com/GetStream/stream-chat-swift/pull/3863)
 
 ## StreamChatUI
 ### 🐞 Fixed

Sources/StreamChat/Repositories/SyncOperations.swift

@@ -122,7 +122,7 @@ final class SyncEventsOperation: AsyncOperation, @unchecked Sendable {
             }
 
             syncRepository?.syncChannelsEvents(
-                channelIds: Array(channelIds),
+                channelIds: Array(channelIds.prefix(100)),
                 lastSyncAt: context.lastSyncAt,
                 isRecovery: recovery
             ) { result in

TestTools/StreamChatTestTools/Mocks/StreamChat/Repositories/SyncRepository_Mock.swift

@@ -12,6 +12,7 @@ final class SyncRepository_Mock: SyncRepository, Spy {
 
     let spyState = SpyState()
     var syncMissingEventsResult: Result<[ChannelId], SyncError>?
+    var syncMissingEvents_syncChannels: [ChannelId]?
 
     convenience init() {
         let apiClient = APIClient_Spy()
@@ -59,6 +60,7 @@ final class SyncRepository_Mock: SyncRepository, Spy {
         completion: @escaping (Result<[ChannelId], SyncError>) -> Void
     ) {
         record()
+        syncMissingEvents_syncChannels = channelIds
         syncMissingEventsResult.map(completion)
     }
 }

Tests/StreamChatTests/Repositories/SyncOperations_Tests.swift

@@ -69,6 +69,27 @@ final class SyncOperations_Tests: XCTestCase {
             times: 1
         )
     }
+    
+    func test_SyncEventsOperation_limitChannelIdsTo100() throws {
+        let context = SyncContext(lastSyncAt: .init())
+        context.localChannelIds = Set((0..<255).map { ChannelId(type: .messaging, id: "\($0)") })
+        try database.createCurrentUser()
+        try database.writeSynchronously { session in
+            session.currentUser?.lastSynchedEventDate = DBDate().addingTimeInterval(-3600)
+        }
+
+        let operation = SyncEventsOperation(syncRepository: syncRepository, context: context, recovery: false)
+        syncRepository.syncMissingEventsResult = .success([.unique])
+
+        operation.startAndWaitForCompletion()
+
+        XCTAssertEqual(syncRepository.syncMissingEvents_syncChannels?.count, 100)
+        XCTAssertCall(
+            "syncChannelsEvents(channelIds:lastSyncAt:isRecovery:completion:)",
+            on: syncRepository,
+            times: 1
+        )
+    }
 
     // MARK: - WatchChannelOperation