Not all warm start cases covered by SDK?

[zhukic]

Problem Statement

Hi!

Sentry SDK version - 7.14.0

Currently, SDK reports the warm start only in case when an application was launched from background state and activity is created with non-null bundle(how to reproduce it).

But, according to the documentation there are another cases like The user backs out of your app but then re-launches it. The process might continue to run, but the app must recreate the activity from scratch using a call to onCreate().

For example, when an application receives a push notification, the process and application are initialized; if we launch the app after that, only activity is created, and it looks like a case for the warm start, but the SDK doesn't report it.

Another case(but I'm not sure if it's a really warm start) - the app goes to the background, the system kills all activities, and then we launch the app. In this case, the process still exists, and only activity is created(can be reproduced with "Don't keep activities" enabled).

We see that the number of warm starts reported by SDK is much less than the number of starts we see in Google Play Console, so covering all such possible cases should reduce the difference.

What do you think?

Solution Brainstorm

No response

[markushi]

@zhukic Thanks for reporting, it definitely looks like we're under-reporting warm app starts. We'll take a look into this.

[markushi]

Instead of dropping warm app starts with older process inits, we should create a new app start transaction once the warm start happens and properly date it back to the second app launch time.

The papa library provides some good reference for the different warm app start types: https://github.com/square/papa/blob/be9dd6d466fbc2de8722aa83d80bfcf6b17317c5/papa/src/main/java/papa/PreLaunchState.kt#L39-L58