Only allow revisions on standard and direct-story-reply messages

SignalServiceKit/MessageBackup/Archivers/ChatItem/MessageBackupTSMessageEditHistoryArchiver.swift

@@ -161,6 +161,39 @@ final class MessageBackupTSMessageEditHistoryArchiver<MessageType: TSMessage>
         context: MessageBackup.ChatArchivingContext,
         builder: Builder
     ) -> MessageBackup.ArchiveInteractionResult<Void> {
+        let unexpectedRevisionsMessageType: ArchiveFrameError.ErrorType.UnexpectedRevisionsMessageType?
+        switch latestRevisionDetails.chatItemType {
+        case .remoteDeletedMessage:
+            // Remote-deleted messages with edit history delete the contents of
+            // their prior revisions, but leave the revisions around as
+            // placeholders. We don't want to archive those, nor do we need to
+            // produce an error, so we bail early.
+            return .success(())
+        case .standardMessage, .directStoryReplyMessage:
+            // These message types are the only ones expected/allowed to have
+            // edit history we want to archive. If we unexpectedly find it on
+            // another message type, we'll drop it and record an error.
+            unexpectedRevisionsMessageType = nil
+        case .contactMessage:
+            unexpectedRevisionsMessageType = .contactMessgae
+        case .stickerMessage:
+            unexpectedRevisionsMessageType = .stickerMessage
+        case .updateMessage:
+            unexpectedRevisionsMessageType = .updateMessage
+        case .paymentNotification:
+            unexpectedRevisionsMessageType = .paymentNotification
+        case .giftBadge:
+            unexpectedRevisionsMessageType = .giftBadge
+        case .viewOnceMessage:
+            unexpectedRevisionsMessageType = .viewOnceMessage
+        }
+        if let unexpectedRevisionsMessageType {
+            return .partialFailure((), [.archiveFrameError(
+                .unexpectedRevisionsOnMessage(unexpectedRevisionsMessageType),
+                latestRevisionMessage.uniqueInteractionId
+            )])
+        }
+
         var partialErrors = [ArchiveFrameError]()
 
         /// The edit history, from oldest revision to newest. This ordering

SignalServiceKit/MessageBackup/Archivers/MessageBackupErrors.swift

@@ -14,6 +14,16 @@ extension MessageBackup {
     /// Error while archiving a single frame.
     public struct ArchiveFrameError<AppIdType: MessageBackupLoggableId>: MessageBackupLoggableError {
         public enum ErrorType {
+            /// Message types for which edit history is unexpected.
+            public enum UnexpectedRevisionsMessageType {
+                case contactMessgae
+                case stickerMessage
+                case updateMessage
+                case paymentNotification
+                case giftBadge
+                case viewOnceMessage
+            }
+
             /// An error occurred serializing the proto.
             /// - Note
             /// Logging the raw error is safe, as it'll just contain proto field
@@ -216,6 +226,9 @@ extension MessageBackup {
             case adHocCallDoesNotHaveCallLinkAsConversationId
             /// An ad hoc call has an invalid start timestamp.
             case invalidAdHocCallTimestamp
+
+            /// A message unexpectedly had edit history.
+            case unexpectedRevisionsOnMessage(UnexpectedRevisionsMessageType)
         }
 
         private let type: ErrorType
@@ -331,7 +344,8 @@ extension MessageBackup {
                     .unviewedViewOnceMessageTooManyAttachments,
                     .callLinkRestrictionsUnknown,
                     .adHocCallDoesNotHaveCallLinkAsConversationId,
-                    .invalidAdHocCallTimestamp:
+                    .invalidAdHocCallTimestamp,
+                    .unexpectedRevisionsOnMessage:
                 // Log any others as we see them.
                 return nil
             }
@@ -396,7 +410,8 @@ extension MessageBackup {
                     .unviewedViewOnceMessageTooManyAttachments,
                     .callLinkRestrictionsUnknown,
                     .adHocCallDoesNotHaveCallLinkAsConversationId,
-                    .invalidAdHocCallTimestamp:
+                    .invalidAdHocCallTimestamp,
+                    .unexpectedRevisionsOnMessage:
                 return .error
             case .contactThreadMissingAddress:
                 // We've seen real-world databases with TSContactThreads that