In update card screen, only update card brand when the card brand has changed

paymentsheet/src/main/java/com/stripe/android/paymentsheet/ui/UpdatePaymentMethodInteractor.kt

@@ -166,23 +166,44 @@ internal class DefaultUpdatePaymentMethodInteractor(
 
     private fun savePaymentMethod() {
         coroutineScope.launch {
-            val newCardBrand = cardBrandChoice.value.brand
-
             error.emit(getInitialError())
             status.emit(UpdatePaymentMethodInteractor.Status.Updating)
 
-            val updateCardBrandResult = updateCardBrandExecutor(
-                displayableSavedPaymentMethod.paymentMethod,
-                newCardBrand
+            val updateCardBrandResult = maybeUpdateCardBrand()
+
+            val errorMessage = getErrorMessageForUpdates(
+                updateCardBrandResult = updateCardBrandResult,
             )
 
-            updateCardBrandResult.onSuccess {
+            if (errorMessage != null) {
+                error.emit(errorMessage)
+            }
+
+            status.emit(UpdatePaymentMethodInteractor.Status.Idle)
+        }
+    }
+
+    private suspend fun maybeUpdateCardBrand(): Result<PaymentMethod>? {
+        val newCardBrand = cardBrandChoice.value.brand
+        return if (cardBrandHasBeenChanged.value) {
+            updateCardBrandExecutor(
+                displayableSavedPaymentMethod.paymentMethod,
+                newCardBrand
+            ).onSuccess {
                 savedCardBrand.emit(CardBrandChoice(brand = newCardBrand, enabled = true))
                 cardBrandHasBeenChanged.emit(false)
-            }.onFailure {
-                error.emit(it.stripeErrorMessage())
             }
-            status.emit(UpdatePaymentMethodInteractor.Status.Idle)
+        } else {
+            null
+        }
+    }
+
+    private fun getErrorMessageForUpdates(
+        updateCardBrandResult: Result<PaymentMethod>?,
+    ): ResolvableString? {
+        return when {
+            updateCardBrandResult?.isFailure == true -> updateCardBrandResult.exceptionOrNull()?.stripeErrorMessage()
+            else -> null
         }
     }
 

paymentsheet/src/test/java/com/stripe/android/paymentsheet/ui/DefaultUpdatePaymentMethodInteractorTest.kt

@@ -212,6 +212,28 @@ class DefaultUpdatePaymentMethodInteractorTest {
         }
     }
 
+    @Test
+    fun updatingCardBrand_cardBrandHasNotChanged_doesNotAttemptUpdate() {
+        val initialPaymentMethod = PaymentMethodFixtures.CARD_WITH_NETWORKS_PAYMENT_METHOD
+        var cardBrandUpdateCalled = false
+
+        @Suppress("UnusedParameter")
+        fun updateCardBrandExecutor(paymentMethod: PaymentMethod, brand: CardBrand): Result<PaymentMethod> {
+            cardBrandUpdateCalled = true
+
+            return Result.success(paymentMethod)
+        }
+
+        runScenario(
+            displayableSavedPaymentMethod = initialPaymentMethod.toDisplayableSavedPaymentMethod(),
+            onUpdateCardBrand = ::updateCardBrandExecutor,
+        ) {
+            interactor.handleViewAction(UpdatePaymentMethodInteractor.ViewAction.SaveButtonPressed)
+
+            assertThat(cardBrandUpdateCalled).isFalse()
+        }
+    }
+
     @Test
     fun saveButtonClick_failure_displaysError() {
         val updateException = IllegalStateException("Not allowed.")