Data Races in IterableEmbeddedManager

[macbellingrath]

Hello, there are several data races in the SDK as of version 6.5.11.

As an example, IterableEmbeddedManager stores some memory for placements and their associated messages. This memory is not protected and is accessed from multiple threads. This can lead to memory corruption and instability. Access to this memory should be synchronized if it accross threads.

class IterableEmbeddedManager: NSObject, IterableInternalEmbeddedManagerProtocol {
    ... 
    private var messages: [Int: [IterableEmbeddedMessage]] = [:]
   ...
    public func getMessages() -> [IterableEmbeddedMessage] { << not isolated
        return Array(messages.values.flatMap { $0 })
    }
...    
      private func retrieveEmbeddedMessages(completion: @escaping () -> Void) {
        apiClient.getEmbeddedMessages()
            .onCompletion(
                receiveValue: { embeddedMessagesPayload in
               ..
                    let processor = EmbeddedMessagingProcessor(currentMessages: self.messages, <<<< URLSession-Delegate Queue 
                                                               fetchedMessages: fetchedMessagesDict)
...
    private func setMessages(_ processor: EmbeddedMessagingProcessor) { << not isolated, called from several different threads
        messages = processor.processedMessagesList() 
        cleanUpTrackedMessageIds(messages)
    }
...
    
    public func reset() {
        let processor = EmbeddedMessagingProcessor(currentMessages: self.messages, fetchedMessages: [:])
        self.setMessages(processor)  << Message access on main thread 

[jena-chakour]

Hey @macbellingrath thanks for surfacing this, our team will take this note into our next internal discussion on upcoming improvements. Let me know in our Support thread if anything misbehaves.