[Bug] Crash @kotlin.KotlinNullPointerException: at mozilla.components.service.fxa.manager.FxaAccountManager.postAuthenticated(FxaAccountManager.kt:36)

[grigoryk]

Filed from mozilla-mobile/fenix#12000

https://crash-stats.mozilla.org/signature/?product=Fenix&signature=kotlin.KotlinNullPointerException%3A%20at%20mozilla.components.service.fxa.manager.FxaAccountManager.postAuthenticated%28FxaAccountManager.kt%3A36%29

kotlin.KotlinNullPointerException
	at mozilla.components.service.fxa.manager.FxaAccountManager.postAuthenticated(FxaAccountManager.kt:36)
	at mozilla.components.service.fxa.manager.FxaAccountManager$postAuthenticated$1.invokeSuspend(FxaAccountManager.kt)
	at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:2)
	at kotlinx.coroutines.DispatchedTask.run(DispatchedTask.kt:19)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1115)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:590)
	at java.lang.Thread.run(Thread.java:818)

┆Issue is synchronized with this Jira Task

[grigoryk]

The obvious thing that can NPE in that stacktrace (unfortunately line numbers are wrong) is fxaDeviceId = account.getCurrentDeviceId()!!.

[grigoryk]

getCurrentDeviceId ends up reading from local state in https://github.com/mozilla/application-services/blob/master/components/fxa-client/src/device.rs#L334-L339:

match self.state.current_device_id {
            Some(ref device_id) => Ok(device_id.to_string()),
            None => Err(ErrorKind::NoCurrentDeviceId.into()),
        }

self.state.current_device_id is set in two places - ensure_capabilities or initialize_device (in fxaclient's device.rs). In the most common scenario (just logging-in, either manually or via pairing) we call initialize_device just before going into postAuthenticated. But, that needs to talk to network, and can fail.
Currently, we assume that this call actually succeeded. If it didn't, we won't have the current_device_id set, and will blow up in postAuthenticated.

[pocmo]

According to Google Play this is our top crash in 79.0.0.

[pocmo]

The following Fenix issue has STRs:
mozilla-mobile/fenix#13064

[Diana-Rus]

Hi, issue is still reproducible with Samsung Galaxy S9 (Android 8) and Google Pixel 3XL (Android 9) on Firefox Release 79.0.1.

As long as you leave the "Approval now required" page, after a second or two and before on desktop is displayed "Firefox Account is connected with Firefox for Android."

Crash link - Samsung Galaxy S9 (Android 8): https://crash-stats.mozilla.org/report/index/25257b31-c0f6-49ec-9892-2b4df0200731
Crash link - google Pixel 3 XL (Android 9): https://crash-stats.mozilla.org/report/index/b4d6be88-4130-4bf7-96cb-e4b8d0200731

Same STR, exception is the timing in step 6:

1. Open browser go to Settings/ Sign in with a QR code.
2. Tap on the "Allow" button from the dialog box.
3. On Firefox Nightly desktop go to firefox.com/pair and tap on the "Show code" button.
4. Scan the provided QR code.
5. Confirm pairing on both mobile and desktop.
6. Leave "Approval now required" page by tapping on deivce back button, after 1 or 2 seconds.
7. Go to Settings/Synced tabs.
8. Wait a couple of seconds.

[grigoryk]

Thanks, @Diana-Rus. These STRs are quite different now, and the stacktrace is different. Before we were dealing with error handling around network failures, and this is something else now. I've filed #7944 to investigate. Thanks for reporting :)

[grigoryk]

@Diana-Rus landed a fix in #7944 - I'll close this issue for now.

We've cut 48.0.12 with this fix in it, which should be available in 79.0.2 fenix release that will be available later today.