EXC_BAD_ACCESS KERN_INVALID_ADDRESS ios 11.2 swift 4.0

Question

I am facing crash in the following code only in iOS 11.2. I am using swift 4.0. I tried to debug for hours to reproduce the crash but could not succeed. Here is the code

func prepareNewConnection(conn:String) -> RTCPeerConnection {

    let uuid = UIDevice.current.identifierForVendor?.uuidString

    localAudioTrack = peerConnectionFactory.audioTrack(withTrackId: uuid!)

        mediaStream = peerConnectionFactory.mediaStream(withStreamId: LOCAL_MEDIA_STREAM_ID)
        if(localAudioTrack != nil && mediaStream != nil)
        {
            mediaStream.addAudioTrack(localAudioTrack!) //Crash on this line
        }

    let pc = peerConnectionFactory.peerConnection(with: rtcConfig, constraints: mediaConstraints, delegate: self)
    if(mediaStream != nil)
    {
        pc.add(mediaStream)
    }

return pc;
}

Here is crashlytics report.

I shall be very thankful for any help.

Why aren't you properly and safely unwrapping `localAudioTrack` and `mediaStream`? — rmaddy, Mar 21 '18 at 03:33
Can you give me example? I am not understanding what do you mean by "properly and safely unwrapping". I will be very thankful. — Fawad Masud, Mar 21 '18 at 03:35
I am checking both localAudioTrack and mediaStream for nil value. — Fawad Masud, Mar 21 '18 at 03:49
But you are not doing it properly. Another thread could set them to `nil`. Safely unwrap them using `if let`. — rmaddy, Mar 21 '18 at 03:53
Can you write in answer editing my code so that I can accept ? Thanks. — Fawad Masud, Mar 21 '18 at 03:57
I have no idea if it actually fixes your issue. It's just a suggestion. — rmaddy, Mar 21 '18 at 03:59
I still could not get it. Can you please give me an example? — Fawad Masud, Mar 21 '18 at 04:10
Read about [Optionals and Optional Binding](https://developer.apple.com/library/content/documentation/Swift/Conceptual/Swift_Programming_Language/TheBasics.html#//apple_ref/doc/uid/TP40014097-CH5-ID309) in the Swift book. — rmaddy, Mar 21 '18 at 04:28
if let ms = mediaStream{ if let at = localAudioTrack{ ms.addAudioTrack(at) } } Is this correct? — Fawad Masud, Mar 21 '18 at 04:52
you can have it this way `if let ms = mediaStream, let at = localAudioTrack { ms.addAudioTrack(at) }` this way you only have one `if-statement` — SquareBox, Apr 03 '18 at 00:42

score 0 · Answer 1 · answered Aug 03 '18 at 16:02

please avoid safely unwrapping, use if let ..

 func prepareNewConnection(conn:String) -> RTCPeerConnection {

   if let uuid = UIDevice.current.identifierForVendor?.uuidString {
localAudioTrack = peerConnectionFactory.audioTrack(withTrackId: uuid) //removed safely Unwrapping
    mediaStream = peerConnectionFactory.mediaStream(withStreamId: LOCAL_MEDIA_STREAM_ID)
 let pc = peerConnectionFactory.peerConnection(with: rtcConfig,constraints: mediaConstraints, delegate: self)
    if(localAudioTrack != nil && mediaStream != nil)
    {
        mediaStream.addAudioTrack(localAudioTrack)
        pc.add(mediaStream) 
    }
  }
 return pc
}

EXC_BAD_ACCESS KERN_INVALID_ADDRESS ios 11.2 swift 4.0

1 Answers1