EXC_BAD_ACCESS on VideoFeed.swift line 104: session.addInput(videoDeviceInput)

[waltersanford]

When trying to scan a credit card after using the camera, the video preview window appears empty and we get Thread 9: EXC_BAD_ACCESS (code=2, address=0x16db6fff8). The line of code that is failing is VideoFeed.swift, line 104: session.addInput(videoDeviceInput).

I've reproduced the error in CardScan - Example by adding a button that opens a standard UIImagePickerController. If you open the camera using the UIImagePickerController 3+ times and then tap the Scan Card button, the error will happen.

[kingst]

Thanks for the bug report, Walter. We're on it.

@jaimejiyepark can you take a look?

[jaimejiyepark]

taking a peek now! let me see if i can reproduce this.

[waltersanford]

PR for fix is here: #90

[waltersanford]

Here is the example app with the changes needed to take photos:
Example.zip

[jaimejiyepark]

Thanks Walter! Taking a look now.

[jaimejiyepark]

Hey @waltersanford ,
I was not able to reproduce your error with your example and with my own implementation with your description or the error.

[jaimejiyepark]

Is there another way to reproduce the error?

[waltersanford]

Interesting, I wonder if its device specific. What device are you testing on? I'll try it on several here.

[jaimejiyepark]

I am testing on my iPhone 8 Plus + iOS13. What about you?

[waltersanford]

Here is what I have so far:
iPhone Xs Max (13.1.2) - EXC_BAD_ACCESS
iPhone 6s Plus (12.4.1) - not happening
iPad Air 2 (13.1.2) - not happening

[waltersanford]

I've updated that original iPhone Xs Max to 13.1.3 and I still get the error. I'll track down another similar device and see if I can reproduce it there.

[jaimejiyepark]

I will also try to run it on an iPhone Xs Max. Will get back to you shortly.

[waltersanford]

I just tried it on an iPhone Xs (13.1.2). I couldn't reproduce the crash in the same way but I was able to cause it to crash using a different set of steps: In my version of the Example app I opened the Scan window 3 times (tapping the Scan Card button, then the Back button) and then tapped the Take Photo button.

[waltersanford]

Good news. Applying the fix in my PR fixes the second crash too. I'm calling it a second crash because it's also an EXC_BAD_ACCESS with code=2 but it doesn't have the same stack trace.

[waltersanford]

So far it's only reproducible on the iPhone Xs and Xs Max. It doesn't happen on the iPhone 8, iPhone 6s Plus or the iPad Air 2.

[jaimejiyepark]

Hey @waltersanford.
Sorry for taking so long getting back to you. After being able to reproduce your error and testing it ourselves, it looks like your fix works! Thank you and we will be closing this issue now.