Unable to log in via Custom Tab on debug build variants

[mileskrell]

Describe the bug
When I try to log in on a debug build variant via a Custom Tab, I get a NullPointerException that causes login to fail.

The NPE happens in LoginActivityIntent.getLoginMode because intent.getSerializableExtra(EXTRA_LOGIN_MODE) returns null and this value is then asserted to be not null.

I've narrowed it down to the following ProGuard rule:

-assumenosideeffects class kotlin.jvm.internal.Intrinsics {
    static void checkNotNull(java.lang.Object);
    # ...
}

When that rule is absent (e.g. in debug build variants), login doesn't work, but when that rule is present (e.g. in release build variants), then LoginActivityIntent.getLoginMode somehow just returns null and login via a Custom Tab works fine. Seems like the ProGuard rule is hiding the issue.

We could make the non-ProGuard behavior explicit by changing the implementation to

fun getLoginMode(intent: Intent) = intent.getSerializableExtra(EXTRA_LOGIN_MODE) as? LoginMode

But I'm not familiar with the intent of the code that calls this function; maybe there's a mistake somewhere else that we should fix instead so that EXTRA_LOGIN_MODE will always be present.

Screenshots or video
The following is what I experience when I install and try to log in with the blueFdroidDebug build variant, built from the v2.5.1 source (i.e. commit c6d6f0f).

login.issue.mp4

Versions
Pachli 2.5.1
Android 14
Server: 4.3.0-alpha.3+glitch

Additional context
Stack trace:

 E  FATAL EXCEPTION: main
    Process: app.pachli, PID: 17131
    java.lang.RuntimeException: Unable to start activity ComponentInfo{app.pachli/app.pachli.feature.login.LoginActivity}: java.lang.NullPointerException
    	at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3946)
    	at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:4126)
    	at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:108)
    	at android.app.servertransaction.TransactionExecutor.executeNonLifecycleItem(TransactionExecutor.java:195)
    	at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:157)
    	at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:90)
    	at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2544)
    	at android.os.Handler.dispatchMessage(Handler.java:107)
    	at android.os.Looper.loopOnce(Looper.java:232)
    	at android.os.Looper.loop(Looper.java:317)
    	at android.app.ActivityThread.main(ActivityThread.java:8501)
    	at java.lang.reflect.Method.invoke(Native Method)
    	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:552)
    	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:878)
    Caused by: java.lang.NullPointerException
    	at app.pachli.core.navigation.LoginActivityIntent$Companion.getLoginMode(Navigation.kt:239)
    	at app.pachli.feature.login.LoginActivity.isAccountMigration(LoginActivity.kt:352)
    	at app.pachli.feature.login.LoginActivity.onCreate(LoginActivity.kt:98)
    	at android.app.Activity.performCreate(Activity.java:8767)
    	...

Affirmation
I have checked other issues for this project (open and closed) and I cannot find one that matches the problem I am reporting.