App crashes occurring in ZPParticipantViewController

[andy.ly (Andy)]

Description
We have been receiving many crash reports for the [ZPParticipantViewController dismissParticipantAlertController:] method. Specific it crashes with Fatal Exception: NSInvalidArgumentException for -[ZPParticipantViewController dismissParticipantAlertController:]: unrecognized selector sent to instance. We were wondering if there were any current workarounds to prevent this crash? Also, is there a timeline on when these crashes will resolved? Please let me know if you need any other information, thank you.

Which Client Mobile SDK version?
5.4.54802.0124

[Michael_Condon (Michael)]

Hey @andy.ly,

Thanks for using the dev forum! It is nice to see you again

Thank you for bringing this to our attention!
Can you provide the following:

• Does this happen consistently?
• Are there any reproduction steps?
• Do you have crash logs?
• Are you using Swift or Objective-C?
• If you are using Objective-C, do you have ARC enabled?
• Are you using the Default UI or Custom UI?
• If there are reproduction steps, can you provide any relevant code?
• Are you seeing this in the MobileRTCSample application?

Thanks!
Michael

[andy.ly (Andy)]

Hey @Michael_Condon,

Nice to see you again as well.

To answer some of your questions:

• Does this happen consistently? - We have not been able to reproduce this ourselves, but have received around 100 reports of this issue in the past week
• Are there any reproduction steps? - Have not been able to find reproducible steps
• Do you have crash logs? - Do not have crash logs for the issue, but we know the crash has to do with this line -[NSOrderedSet initWithSet:copyItems:]. States that it does not recognize the selector.
• Are you using Swift or Objective-C? - We are using Objective-C
• If you are using Objective-C, do you have ARC enabled? - We have ARC enabled
• Are you using the Default UI or Custom UI? - Default UI
• If there are reproduction steps, can you provide any relevant code?
• Are you seeing this in the MobileRTCSample application? - Have not tested this issue on the MobileRTCSample application

[Michael_Condon (Michael)]

Hey @andy.ly,

Thank you for getting back to me.

Unfortunately, without any reproduction steps or crash logs the engineers are not going to be able to find the root cause of the issue. However, here are some suggestions that have resolved crashes similar to this one in the past.

• Make sure that your MobileRTCMeetingServiceDelegate will not become nil at any point during a meeting. There have been sparse crashes from this delegate becoming nil after minimizing the meeting view and navigating around the app for a while.
• Verify you have called all of the necessary AppDelegate calls:

• (void)applicationWillResignActive:(UIApplication *)application
  {
  [[MobileRTC sharedRTC] appWillResignActive];
  }

• (void)applicationDidEnterBackground:(UIApplication *)application
  {
  [[MobileRTC sharedRTC] appDidEnterBackgroud];
  }

• (void)applicationDidBecomeActive:(UIApplication *)application
  {
  [[MobileRTC sharedRTC] appDidBecomeActive];
  }

• (void)applicationWillTerminate:(UIApplication *)application
  {
  [[MobileRTC sharedRTC] appWillTerminate];
  }

• Verify that background modes are enabled. It is possible this is caused by the view being improperly released during a backgrounding of the application.

Thanks!
Michael

[andy.ly (Andy)]

Hello @Michael_Condon ,

Thanks for the reply.

I have confirmed that our app does not set MobileRTCMeetingServiceDelegate as nil during a meeting and that we call all of the necessary AppDelegate calls. For your last point, how do we verify that background modes are enabled? Thank you.

[Michael_Condon (Michael)]

Hey @andy.ly,

If you go to your Xcode target settings, there will be a tab that says “Signing & Capabilities”. In that tab’s section, there should be a subsection that says “Background Modes”. It should look like this:

Thanks!
Michael