Eagerly finish activities if they're started with invalid args.

payments-core/detekt-baseline.xml

@@ -199,6 +199,7 @@
     <ID>ReturnCount:FraudDetectionDataJsonParser.kt$FraudDetectionDataJsonParser$override fun parse(json: JSONObject): FraudDetectionData?</ID>
     <ID>ReturnCount:PaymentAuthWebViewClient.kt$PaymentAuthWebViewClient$private fun isReturnUrl(uri: Uri): Boolean</ID>
     <ID>ReturnCount:WalletJsonParser.kt$WalletJsonParser$override fun parse(json: JSONObject): Wallet?</ID>
+    <ID>SwallowedException:ActivityUtils.kt$e: IllegalArgumentException</ID>
     <ID>SwallowedException:PaymentUtils.kt$PaymentUtils$e: ClassCastException</ID>
     <ID>SwallowedException:Stripe.kt$Stripe$exception: CardException</ID>
     <ID>ThrowsCount:StripeApiRepository.kt$StripeApiRepository$@Throws( InvalidRequestException::class, AuthenticationException::class, CardException::class, APIException::class ) private fun handleApiError(response: StripeResponse&lt;String>)</ID>

payments-core/src/main/java/com/stripe/android/utils/ActivityUtils.kt

@@ -0,0 +1,13 @@
+package com.stripe.android.utils
+
+import android.app.Activity
+
+internal fun Activity.argsAreInvalid(argsProvider: () -> Unit): Boolean {
+    return try {
+        argsProvider()
+        false
+    } catch (e: IllegalArgumentException) {
+        finish()
+        true
+    }
+}

payments-core/src/main/java/com/stripe/android/view/AddPaymentMethodActivity.kt

@@ -20,6 +20,7 @@ import com.stripe.android.Stripe
 import com.stripe.android.databinding.AddPaymentMethodActivityBinding
 import com.stripe.android.model.PaymentMethod
 import com.stripe.android.model.PaymentMethodCreateParams
+import com.stripe.android.utils.argsAreInvalid
 
 /**
  * Activity used to display a [AddPaymentMethodView] and receive the resulting
@@ -89,6 +90,9 @@ class AddPaymentMethodActivity : StripeActivity() {
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
+        if (argsAreInvalid { args }) {
+            return
+        }
         configureView(args)
         setResult(
             Activity.RESULT_OK,

payments-core/src/main/java/com/stripe/android/view/PaymentFlowActivity.kt

@@ -14,6 +14,7 @@ import com.stripe.android.R
 import com.stripe.android.databinding.PaymentFlowActivityBinding
 import com.stripe.android.model.ShippingInformation
 import com.stripe.android.model.ShippingMethod
+import com.stripe.android.utils.argsAreInvalid
 
 /**
  * Activity containing a two-part payment flow that allows users to provide a shipping address
@@ -61,6 +62,10 @@ class PaymentFlowActivity : StripeActivity() {
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
 
+        if (argsAreInvalid { args }) {
+            return
+        }
+
         val args = PaymentFlowActivityStarter.Args.create(intent)
         args.windowFlags?.let { window.addFlags(it) }
 

payments-core/src/main/java/com/stripe/android/view/PaymentMethodsActivity.kt

@@ -21,6 +21,7 @@ import com.stripe.android.R
 import com.stripe.android.core.exception.StripeException
 import com.stripe.android.databinding.PaymentMethodsActivityBinding
 import com.stripe.android.model.PaymentMethod
+import com.stripe.android.utils.argsAreInvalid
 import com.stripe.android.view.i18n.TranslatorManager
 
 /**
@@ -77,6 +78,8 @@ class PaymentMethodsActivity : AppCompatActivity() {
         )
     }
 
+    private var earlyExitDueToIllegalState: Boolean = false
+
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         if (customerSession.isFailure) {
@@ -86,6 +89,10 @@ class PaymentMethodsActivity : AppCompatActivity() {
             )
             return
         }
+        if (argsAreInvalid { args }) {
+            earlyExitDueToIllegalState = true
+            return
+        }
 
         setContentView(viewBinding.root)
 
@@ -283,7 +290,9 @@ class PaymentMethodsActivity : AppCompatActivity() {
     }
 
     override fun onDestroy() {
-        viewModel.selectedPaymentMethodId = adapter.selectedPaymentMethod?.id
+        if (!earlyExitDueToIllegalState) {
+            viewModel.selectedPaymentMethodId = adapter.selectedPaymentMethod?.id
+        }
         super.onDestroy()
     }
 

payments-core/src/test/java/com/stripe/android/view/ActivityScenarioFactory.kt

@@ -22,6 +22,12 @@ internal class ActivityScenarioFactory(
         )
     }
 
+    internal inline fun <reified T : Activity> create(): ActivityScenario<T> {
+        return ActivityScenario.launch(
+            Intent(context, T::class.java)
+        )
+    }
+
     fun createAddPaymentMethodActivity() = create<AddPaymentMethodActivity>(
         AddPaymentMethodActivityStarter.Args.Builder()
             .setPaymentMethodType(PaymentMethod.Type.Card)

payments-core/src/test/java/com/stripe/android/view/AddPaymentMethodActivityTest.kt

@@ -9,6 +9,7 @@ import android.widget.ProgressBar
 import android.widget.TextView
 import androidx.core.view.isGone
 import androidx.core.view.isVisible
+import androidx.lifecycle.Lifecycle
 import androidx.lifecycle.LiveData
 import androidx.lifecycle.MutableLiveData
 import androidx.test.core.app.ApplicationProvider
@@ -69,6 +70,13 @@ class AddPaymentMethodActivityTest {
         CustomerSession.instance = customerSession
     }
 
+    @Test
+    fun testActivityIsFinishedWhenNoArgsPassed() {
+        activityScenarioFactory.create<AddPaymentMethodActivity>().use { activityScenario ->
+            assertThat(activityScenario.state).isEqualTo(Lifecycle.State.DESTROYED)
+        }
+    }
+
     @Test
     fun testConstructionForLocal() {
         activityScenarioFactory.create<AddPaymentMethodActivity>(

payments-core/src/test/java/com/stripe/android/view/PaymentFlowActivityTest.kt

@@ -5,6 +5,7 @@ import android.content.Context
 import androidx.arch.core.executor.testing.InstantTaskExecutorRule
 import androidx.core.view.isGone
 import androidx.core.view.isVisible
+import androidx.lifecycle.Lifecycle
 import androidx.test.core.app.ApplicationProvider
 import com.google.common.truth.Truth.assertThat
 import com.stripe.android.ApiKeyFixtures
@@ -49,6 +50,13 @@ class PaymentFlowActivityTest {
         CustomerSession.initCustomerSession(context, ephemeralKeyProvider)
     }
 
+    @Test
+    fun launchPaymentFlowActivity_withInvalidArgs_finishesActivity() {
+        activityScenarioFactory.create<PaymentFlowActivity>().use { activityScenario ->
+            assertThat(activityScenario.state).isEqualTo(Lifecycle.State.DESTROYED)
+        }
+    }
+
     @Test
     fun launchPaymentFlowActivity_withHideShippingInfoConfig_hidesShippingInfoView() {
         activityScenarioFactory.create<PaymentFlowActivity>(

payments-core/src/test/java/com/stripe/android/view/PaymentMethodsActivityTest.kt

@@ -3,7 +3,9 @@ package com.stripe.android.view
 import android.app.Activity.RESULT_CANCELED
 import android.content.Context
 import android.view.View
+import androidx.lifecycle.Lifecycle
 import androidx.test.core.app.ApplicationProvider
+import com.google.common.truth.Truth.assertThat
 import com.stripe.android.ApiKeyFixtures
 import com.stripe.android.CustomerSession
 import com.stripe.android.PaymentConfiguration
@@ -44,6 +46,13 @@ class PaymentMethodsActivityTest {
         PaymentConfiguration.init(context, ApiKeyFixtures.FAKE_PUBLISHABLE_KEY)
     }
 
+    @Test
+    fun onCreate_finishesActivityWhenArgsAreMissing() {
+        activityScenarioFactory.create<PaymentMethodsActivity>().use { activityScenario ->
+            assertThat(activityScenario.state).isEqualTo(Lifecycle.State.DESTROYED)
+        }
+    }
+
     @Test
     fun onCreate_callsApiAndDisplaysProgressBarWhileWaiting() {
         activityScenarioFactory.create<PaymentMethodsActivity>(