Fix converting deleted database objects

CHANGELOG.md

@@ -14,6 +14,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 ### 🐞 Fixed
 - Fix connection not resuming after guest user goes to background [#3483](https://github.com/GetStream/stream-chat-swift/pull/3483)
 - Fix empty channel list if the channel list filter contains OR statement with only custom filtering keys [#3482](https://github.com/GetStream/stream-chat-swift/pull/3482)
+- Fix not returning models with empty properties when the underlying database model was deleted [#3497](https://github.com/GetStream/stream-chat-swift/pull/3497)
+- Fix an issue where deleting current user in the local database cleared member data in channels [#3497](https://github.com/GetStream/stream-chat-swift/pull/3497)
 - Fix rare crashes when accessing the current user object [#3500](https://github.com/GetStream/stream-chat-swift/pull/3500)
 ### ⚡ Performance
 - Avoid creating `CurrentChatUserController` for reading user privacy settings which is more expensive than just reading the data from the local database [#3502](https://github.com/GetStream/stream-chat-swift/pull/3502)

Sources/StreamChat/Database/DTOs/AttachmentDTO.swift

@@ -261,6 +261,8 @@ private extension AttachmentDTO {
 extension AttachmentDTO {
     /// Snapshots the current state of `AttachmentDTO` and returns an immutable model object from it.
     func asAnyModel() -> AnyChatMessageAttachment? {
+        guard !isDeleted else { return nil }
+
         guard let id = attachmentID else {
             log.debug("Attachment failed to be converted to model because ID is invalid.")
             return nil

Sources/StreamChat/Database/DTOs/ChannelConfigDTO.swift

@@ -26,7 +26,8 @@ final class ChannelConfigDTO: NSManagedObject {
     @NSManaged var commands: NSOrderedSet
 
     func asModel() throws -> ChannelConfig {
-        .init(
+        try isNotDeleted()
+        return .init(
             reactionsEnabled: reactionsEnabled,
             typingEventsEnabled: typingEventsEnabled,
             readEventsEnabled: readEventsEnabled,

Sources/StreamChat/Database/DTOs/ChannelDTO.swift

@@ -470,6 +470,7 @@ extension ChatChannel {
         guard StreamRuntimeCheck._canFetchRelationship(currentDepth: depth) else {
             throw RecursionLimitError()
         }
+        try dto.isNotDeleted()
         guard let cid = try? ChannelId(cid: dto.cid), let context = dto.managedObjectContext else {
             throw InvalidModel(dto)
         }

Sources/StreamChat/Database/DTOs/ChannelReadDTO.swift

@@ -18,7 +18,10 @@ class ChannelReadDTO: NSManagedObject {
 
     override func willSave() {
         super.willSave()
-
+
+        guard !isDeleted else {
+            return
+        }
         // When the read is updated, we need to propagate this change up to holding channel
         if hasPersistentChangedValues, !channel.hasChanges, !channel.isDeleted {
             // this will not change object, but mark it as dirty, triggering updates
@@ -201,7 +204,8 @@ extension ChannelReadDTO {
 
 extension ChatChannelRead {
     fileprivate static func create(fromDTO dto: ChannelReadDTO) throws -> ChatChannelRead {
-        try .init(
+        try dto.isNotDeleted()
+        return try .init(
             lastReadAt: dto.lastReadAt.bridgeDate,
             lastReadMessageId: dto.lastReadMessageId,
             unreadMessagesCount: Int(dto.unreadMessageCount),

Sources/StreamChat/Database/DTOs/CommandDTO.swift

@@ -13,7 +13,8 @@ final class CommandDTO: NSManagedObject {
     @NSManaged var args: String
 
     func asModel() throws -> Command {
-        .init(
+        try isNotDeleted()
+        return .init(
             name: name,
             description: desc,
             set: set,

Sources/StreamChat/Database/DTOs/CurrentUserDTO.swift

@@ -215,6 +215,8 @@ extension CurrentUserDTO {
 
 extension CurrentChatUser {
     fileprivate static func create(fromDTO dto: CurrentUserDTO) throws -> CurrentChatUser {
+        try dto.isNotDeleted()
+
         let user = dto.user
 
         var extraData = [String: RawJSON]()

Sources/StreamChat/Database/DTOs/DeviceDTO.swift

@@ -45,6 +45,7 @@ extension DeviceDTO {
 
 extension DeviceDTO {
     func asModel() throws -> Device {
-        Device(id: id, createdAt: createdAt?.bridgeDate)
+        try isNotDeleted()
+        return Device(id: id, createdAt: createdAt?.bridgeDate)
     }
 }

Sources/StreamChat/Database/DTOs/MemberModelDTO.swift

@@ -180,6 +180,8 @@ extension MemberDTO {
 
 extension ChatChannelMember {
     fileprivate static func create(fromDTO dto: MemberDTO) throws -> ChatChannelMember {
+        try dto.isNotDeleted()
+
         let extraData: [String: RawJSON]
         do {
             extraData = try JSONDecoder.default.decode([String: RawJSON].self, from: dto.user.extraData)

Sources/StreamChat/Database/DTOs/MessageDTO.swift

@@ -1339,6 +1339,7 @@ private extension ChatMessage {
         guard let context = dto.managedObjectContext else {
             throw InvalidModel(dto)
         }
+        try dto.isNotDeleted()
 
         id = dto.id
         cid = try? dto.cid.map { try ChannelId(cid: $0) }

Sources/StreamChat/Database/DTOs/MessageReactionDTO.swift

@@ -205,6 +205,8 @@ extension MessageReactionDTO {
 
     /// Snapshots the current state of `MessageReactionDTO` and returns an immutable model object from it.
     func asModel() throws -> ChatMessageReaction {
+        try isNotDeleted()
+
         let decodedExtraData: [String: RawJSON]
 
         if let extraData = self.extraData, !extraData.isEmpty {

Sources/StreamChat/Database/DTOs/MessageReactionGroupDTO.swift

@@ -50,14 +50,16 @@ extension Set where Element == MessageReactionGroupDTO {
 
     func asModel() -> [MessageReactionType: ChatMessageReactionGroup] {
         reduce(into: [:]) { partialResult, groupDTO in
-            partialResult[MessageReactionType(rawValue: groupDTO.type)] = groupDTO.asModel()
+            guard let model = try? groupDTO.asModel() else { return }
+            partialResult[MessageReactionType(rawValue: groupDTO.type)] = model
         }
     }
 }
 
 extension MessageReactionGroupDTO {
-    func asModel() -> ChatMessageReactionGroup {
-        .init(
+    func asModel() throws -> ChatMessageReactionGroup {
+        try isNotDeleted()
+        return .init(
             type: MessageReactionType(rawValue: type),
             sumScores: Int(sumScores),
             count: Int(count),

Sources/StreamChat/Database/DTOs/NSManagedObject+Validation.swift

@@ -15,6 +15,11 @@ extension NSManagedObject {
         }
         return true
     }
+
+    func isNotDeleted() throws {
+        guard isDeleted else { return }
+        throw DeletedModel(self)
+    }
 }
 
 struct InvalidModel: LocalizedError {
@@ -31,4 +36,18 @@ struct InvalidModel: LocalizedError {
     }
 }
 
+struct DeletedModel: LocalizedError {
+    let id: NSManagedObjectID
+    let entityName: String?
+
+    init(_ model: NSManagedObject) {
+        id = model.objectID
+        entityName = model.entity.name
+    }
+
+    var errorDescription: String? {
+        "\(entityName ?? "Unknown") object with ID \(id) is deleted"
+    }
+}
+
 struct RecursionLimitError: LocalizedError {}

Sources/StreamChat/Database/DTOs/PollDTO.swift

@@ -31,6 +31,10 @@ class PollDTO: NSManagedObject {
     override func willSave() {
         super.willSave()
 
+        guard !isDeleted else {
+            return
+        }
+
         // When the poll is updated, trigger message FRC update.
         if let message = self.message, hasPersistentChangedValues, !message.hasChanges, !message.isDeleted {
             message.id = message.id
@@ -82,6 +86,8 @@ extension PollDTO {
 
 extension PollDTO {
     func asModel() throws -> Poll {
+        try isNotDeleted()
+
         var extraData: [String: RawJSON] = [:]
         if let custom,
            !custom.isEmpty,

Sources/StreamChat/Database/DTOs/PollOptionDTO.swift

@@ -58,6 +58,8 @@ extension PollOptionDTO {
 
 extension PollOptionDTO {
     func asModel() throws -> PollOption {
+        try isNotDeleted()
+
         var extraData: [String: RawJSON] = [:]
         if let custom,
            !custom.isEmpty,

Sources/StreamChat/Database/DTOs/PollVoteDTO.swift

@@ -22,6 +22,10 @@ class PollVoteDTO: NSManagedObject {
     override func willSave() {
         super.willSave()
 
+        guard !isDeleted else {
+            return
+        }
+
         // When the poll is updated, trigger message FRC update.
         if let message = poll?.message, hasPersistentChangedValues, !message.hasChanges, !message.isDeleted {
             message.id = message.id
@@ -75,7 +79,8 @@ extension PollVoteDTO {
 
 extension PollVoteDTO {
     func asModel() throws -> PollVote {
-        try PollVote(
+        try isNotDeleted()
+        return try PollVote(
             id: id,
             createdAt: createdAt.bridgeDate,
             updatedAt: updatedAt.bridgeDate,

Sources/StreamChat/Database/DTOs/ThreadDTO.swift

@@ -143,6 +143,8 @@ extension ThreadDTO {
 
 extension ThreadDTO {
     func asModel() throws -> ChatThread {
+        try isNotDeleted()
+
         let extraData: [String: RawJSON]
         do {
             extraData = try JSONDecoder.default.decode([String: RawJSON].self, from: self.extraData)

Sources/StreamChat/Database/DTOs/ThreadParticipantDTO.swift

@@ -46,7 +46,8 @@ extension ThreadParticipantDTO {
 
 extension ThreadParticipantDTO {
     func asModel() throws -> ThreadParticipant {
-        try .init(
+        try isNotDeleted()
+        return try .init(
             user: user.asModel(),
             threadId: threadId,
             createdAt: createdAt.bridgeDate,

Sources/StreamChat/Database/DTOs/ThreadReadDTO.swift

@@ -15,6 +15,10 @@ class ThreadReadDTO: NSManagedObject {
     override func willSave() {
         super.willSave()
 
+        guard !isDeleted else {
+            return
+        }
+
         // When the read is updated, we need to propagate this change up to holding thread
         if hasPersistentChangedValues, !thread.hasChanges, !thread.isDeleted {
             // this will not change object, but mark it as dirty, triggering updates
@@ -70,7 +74,8 @@ extension ThreadReadDTO {
 
 extension ThreadReadDTO {
     func asModel() throws -> ThreadRead {
-        try .init(
+        try isNotDeleted()
+        return try .init(
             user: user.asModel(),
             lastReadAt: lastReadAt?.bridgeDate,
             unreadMessagesCount: Int(unreadMessagesCount)

Sources/StreamChat/Database/DTOs/UserDTO.swift

@@ -40,6 +40,10 @@ class UserDTO: NSManagedObject {
     override func willSave() {
         super.willSave()
 
+        guard !isDeleted else {
+            return
+        }
+
         // We need to propagate fake changes to other models so that it triggers FRC
         // updates for other entities. We also need to check that these models
         // don't have changes already, otherwise it creates an infinite loop.
@@ -227,6 +231,8 @@ extension UserDTO {
 
 extension ChatUser {
     fileprivate static func create(fromDTO dto: UserDTO) throws -> ChatUser {
+        try dto.isNotDeleted()
+
         let extraData: [String: RawJSON]
         do {
             extraData = try JSONDecoder.default.decode([String: RawJSON].self, from: dto.extraData)

Sources/StreamChat/Database/StreamChatModel.xcdatamodeld/StreamChatModel.xcdatamodel/contents

@@ -152,7 +152,7 @@
         <relationship name="devices" optional="YES" toMany="YES" deletionRule="Nullify" destinationEntity="DeviceDTO" inverseName="user" inverseEntity="DeviceDTO"/>
         <relationship name="flaggedMessages" optional="YES" toMany="YES" deletionRule="Nullify" destinationEntity="MessageDTO" inverseName="flaggedBy" inverseEntity="MessageDTO"/>
         <relationship name="flaggedUsers" optional="YES" toMany="YES" deletionRule="Nullify" destinationEntity="UserDTO" inverseName="flaggedBy" inverseEntity="UserDTO"/>
-        <relationship name="mutedUsers" toMany="YES" deletionRule="Cascade" destinationEntity="UserDTO" inverseName="mutedBy" inverseEntity="UserDTO"/>
+        <relationship name="mutedUsers" toMany="YES" deletionRule="Nullify" destinationEntity="UserDTO" inverseName="mutedBy" inverseEntity="UserDTO"/>
         <relationship name="user" optional="YES" maxCount="1" deletionRule="Nullify" destinationEntity="UserDTO" inverseName="currentUser" inverseEntity="UserDTO"/>
         <uniquenessConstraints>
             <uniquenessConstraint>

Sources/StreamChat/Repositories/PollsRepository.swift

@@ -144,12 +144,18 @@ class PollsRepository {
         voteId: String,
         completion: ((Error?) -> Void)? = nil
     ) {
-        var pollVote: PollVote?
+        var exists = false
+        var answerText: String?
+        var optionId: String?
+        var userId: UserId?
         var filterHash: String?
         database.write { session in
             let voteDto = try session.removePollVote(with: voteId, pollId: pollId)
+            exists = voteDto != nil
             filterHash = voteDto?.queries?.first?.filterHash
-            pollVote = try voteDto?.asModel()
+            answerText = voteDto?.answerText
+            optionId = voteDto?.optionId
+            userId = voteDto?.user?.id
         } completion: { [weak self] error in
             if error == nil {
                 self?.apiClient.request(
@@ -159,14 +165,14 @@ class PollsRepository {
                         voteId: voteId
                     )
                 ) {
-                    if $0.error != nil, $0.error?.isBackendNotFound404StatusCode == false, let pollVote {
+                    if $0.error != nil, $0.error?.isBackendNotFound404StatusCode == false, exists {
                         self?.database.write { session in
                             _ = try session.savePollVote(
                                 voteId: voteId,
                                 pollId: pollId,
-                                optionId: pollVote.optionId,
-                                answerText: pollVote.answerText,
-                                userId: pollVote.user?.id,
+                                optionId: optionId,
+                                answerText: answerText,
+                                userId: userId,
                                 query: nil
                             )
                             try? session.linkVote(with: voteId, in: pollId, to: filterHash)

Tests/StreamChatTests/Database/DTOs/CurrentUserDTO_Tests.swift

@@ -289,4 +289,47 @@ final class CurrentUserModelDTO_Tests: XCTestCase {
         XCTAssertEqual(true, loadedCurrentUser.privacySettings.readReceipts?.enabled)
         XCTAssertEqual(true, loadedCurrentUser.privacySettings.typingIndicators?.enabled)
     }
+
+    func test_deletingCurrentUser() throws {
+        let currentUserId = "current_user_id"
+        let mutedUserId = "muted_user_id"
+        let cid = ChannelId.unique
+        try database.writeSynchronously { session in
+            try session.saveCurrentUser(
+                payload: .dummy(
+                    userId: currentUserId,
+                    role: .admin,
+                    mutedUsers: [.dummy(
+                        userId: mutedUserId
+                    )]
+                )
+            )
+            try session.saveChannel(
+                payload: .dummy(
+                    channel: .dummy(cid: cid),
+                    members: [
+                        .dummy(user: .dummy(userId: currentUserId)),
+                        .dummy(user: .dummy(userId: mutedUserId))
+                    ]
+                )
+            )
+        }
+        try database.readSynchronously { session in
+            guard let channelDTO = session.channel(cid: cid) else { throw ClientError.ChannelDoesNotExist(cid: cid) }
+            let channel = try channelDTO.asModel()
+            let memberIds = channel.lastActiveMembers.map(\.id).sorted()
+            XCTAssertEqual([currentUserId, mutedUserId].sorted(), memberIds)
+        }
+        // Delete current user which should not clear member ids of the channel
+        try database.writeSynchronously { session in
+            guard let currentUserDTO = session.currentUser else { throw ClientError.CurrentUserDoesNotExist() }
+            (session as! NSManagedObjectContext).delete(currentUserDTO)
+        }
+        try database.writeSynchronously { session in
+            guard let channelDTO = session.channel(cid: cid) else { throw ClientError.ChannelDoesNotExist(cid: cid) }
+            let channel = try channelDTO.asModel()
+            let memberIds = channel.lastActiveMembers.map(\.id).sorted()
+            XCTAssertEqual([currentUserId, mutedUserId].sorted(), memberIds)
+        }
+    }
 }