PopupBridge.mWebView / mContext null after process kill

[herbeth1u]

General information

• SDK/Library version: 2.0.0
• Android Version and Device: Multiple devices from multiple OEMs (60% Xiaomi Mi A2 Lite, then BlackBerry, Sony and WIKO), all Android versions (6, 8, 9, 10).

Issue description

Hello again. After some tests following #25 , we've managed to reproduce the crash so we're creating a new issue as mentioned in the previous issue. The stacktrace as a reminder:

Caused by java.lang.NullPointerException: Attempt to invoke virtual method 'boolean android.view.View.post(java.lang.Runnable)' on a null object reference
       at com.braintreepayments.popupbridge.PopupBridge.runJavaScriptInWebView(PopupBridge.java:100)
       at com.braintreepayments.popupbridge.PopupBridge.onBrowserSwitchResult(PopupBridge.java:153)
       at com.braintreepayments.browserswitch.BrowserSwitchFragment.onResume(BrowserSwitchFragment.java:73)
       at androidx.fragment.app.Fragment.performResume(Fragment.java:2747)
       at androidx.fragment.app.FragmentStateManager.resume(FragmentStateManager.java:373)
       at androidx.fragment.app.FragmentManager.moveToState(FragmentManager.java:1199)
       at androidx.fragment.app.FragmentManager.moveToState(FragmentManager.java:1356)
       at androidx.fragment.app.FragmentManager.moveFragmentToExpectedState(FragmentManager.java:1434)
       at androidx.fragment.app.FragmentManager.moveToState(FragmentManager.java:1497)
       at androidx.fragment.app.FragmentManager.dispatchStateChange(FragmentManager.java:2625)
       at androidx.fragment.app.FragmentManager.dispatchResume(FragmentManager.java:2589)
       at androidx.fragment.app.FragmentController.dispatchResume(FragmentController.java:269)
       at androidx.fragment.app.FragmentActivity.onResumeFragments(FragmentActivity.java:478)
       at androidx.fragment.app.FragmentActivity.onPostResume(FragmentActivity.java:467)
       at androidx.appcompat.app.AppCompatActivity.onPostResume(AppCompatActivity.java:195)
       at android.app.Activity.performResume(Activity.java:7184)
       at android.app.ActivityThread.performResumeActivity(ActivityThread.java:3694)
       at android.app.ActivityThread.handleResumeActivity(ActivityThread.java:3766)
       at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2939)
       at android.app.ActivityThread.-wrap11(ActivityThread.java)
       at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1615)
       at android.os.Handler.dispatchMessage(Handler.java:105)
       at android.os.Looper.loop(Looper.java:231)
       at android.app.ActivityThread.main(ActivityThread.java:6749)
       at java.lang.reflect.Method.invoke(Method.java)
       at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240)
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767)

Steps to reproduce

FYI we are using PopupBridge for Paypal.

1. Initialize the SDK as mentioned in the docs (at this point we've made sure our webview cannot be null) :

webView?.let { PopupBridge.newInstance(activity, it) }

2. Click on "Buy with Paypal" : the Paypal Chrome Tabs opens.
3. Log in to Paypal if necessary but don't click on "Buy".
4. Trigger a process kill (see here for more information on how to simulate a process kill).
5. Go back to the application : the Paypal Chrome Tabs restarts and loads again properly.
6. Click on "Buy".
7. The PopupBridge fragment is recreated, but its data initialized in newInstance and not saved in a Bundle have been erased (including mWebView and mContext). When going in onResume, the NPE occurs.

Again feel free to ask for more details!
Thank you.

[sshropshire]

Hi @herbeth1u thanks again for using the sdk. I tried reproducing in our demo application and am unable to reproduce. I do however see the concern. May I trouble you for a screen-capture as well?

Theoretically, I'm unable to imagine how WebView can become null if you're certain that a non-null reference is being passed into the PopupBridge::newInstance method.

[herbeth1u]

Hi @sshropshire , we have recorded a video showcasing the crash. For obvious confidentiality issues, we would like to forward it to you in a private message. However it doesn't seem to be possible to send a PM on Github.
Do you perhaps have a public email address or any other private means of communication so we can send you the video?
Thanks.

[sshropshire]

Hello @herbeth1u apologies for the late response. We are able to reproduce similar behavior in our demo application, and it has to do with the deep link back into the PopupBridgeActivity. It seems that Android isn't invoking the deep link after a process kill. We are investigating the issue.

[sarahkoop]

This fix is released in 4.0.0-beta2.

[sshropshire]

Version 4.0.0 is now generally available.