Add check for empty play purchase payment token

5 files changed, 71 insertions, 2 deletions

diff --git a/android/lib/billing/build.gradle.kts b/android/lib/billing/build.gradle.kts
index 46554cf956..d9b4c4dc68 100644
--- a/android/lib/billing/build.gradle.kts
+++ b/android/lib/billing/build.gradle.kts
@@ -62,6 +62,9 @@ dependencies {
     // Management service
     implementation(projects.lib.daemonGrpc)
 
+    // Logger
+    implementation(libs.kermit)
+
     // Test dependencies
     testRuntimeOnly(Dependencies.junitJupiterEngine)
 
diff --git a/android/lib/billing/src/main/kotlin/net/mullvad/mullvadvpn/lib/billing/BillingPaymentRepository.kt b/android/lib/billing/src/main/kotlin/net/mullvad/mullvadvpn/lib/billing/BillingPaymentRepository.kt
index 540a8ad929..39cc584a57 100644
--- a/android/lib/billing/src/main/kotlin/net/mullvad/mullvadvpn/lib/billing/BillingPaymentRepository.kt
+++ b/android/lib/billing/src/main/kotlin/net/mullvad/mullvadvpn/lib/billing/BillingPaymentRepository.kt
@@ -2,8 +2,12 @@ package net.mullvad.mullvadvpn.lib.billing
 
 import android.app.Activity
 import arrow.core.Either
+import arrow.core.flatMap
+import arrow.core.left
 import arrow.core.raise.either
 import arrow.core.raise.ensure
+import arrow.core.right
+import co.touchlab.kermit.Logger
 import com.android.billingclient.api.BillingClient.BillingResponseCode
 import com.android.billingclient.api.Purchase
 import kotlinx.coroutines.flow.Flow
@@ -19,6 +23,7 @@ import net.mullvad.mullvadvpn.lib.billing.extension.toPurchaseResult
 import net.mullvad.mullvadvpn.lib.billing.model.BillingException
 import net.mullvad.mullvadvpn.lib.billing.model.PurchaseEvent
 import net.mullvad.mullvadvpn.lib.model.PlayPurchase
+import net.mullvad.mullvadvpn.lib.model.PlayPurchaseInitError
 import net.mullvad.mullvadvpn.lib.model.PlayPurchasePaymentToken
 import net.mullvad.mullvadvpn.lib.payment.PaymentRepository
 import net.mullvad.mullvadvpn.lib.payment.ProductIds
@@ -78,7 +83,7 @@ class BillingPaymentRepository(
         // Get transaction id
         emit(PurchaseResult.FetchingObfuscationId)
         val obfuscatedId: PlayPurchasePaymentToken =
-            initialisePurchase()
+            initializePurchase()
                 .fold(
                     {
                         emit(PurchaseResult.Error.TransactionIdError(productId, null))
@@ -148,7 +153,15 @@ class BillingPaymentRepository(
             .bind()
     }
 
-    private suspend fun initialisePurchase() = playPurchaseRepository.initializePlayPurchase()
+    private suspend fun initializePurchase() =
+        playPurchaseRepository.initializePlayPurchase().flatMap {
+            if (it.value.isNotEmpty()) {
+                it.right()
+            } else {
+                Logger.e("PlayPurchasePaymentToken is empty")
+                PlayPurchaseInitError.OtherError.left()
+            }
+        }
 
     private suspend fun verifyPurchase(purchase: Purchase) =
         playPurchaseRepository.verifyPlayPurchase(
diff --git a/android/lib/billing/src/main/kotlin/net/mullvad/mullvadvpn/lib/billing/BillingRepository.kt b/android/lib/billing/src/main/kotlin/net/mullvad/mullvadvpn/lib/billing/BillingRepository.kt
index 77eaea03a6..2e9f956d07 100644
--- a/android/lib/billing/src/main/kotlin/net/mullvad/mullvadvpn/lib/billing/BillingRepository.kt
+++ b/android/lib/billing/src/main/kotlin/net/mullvad/mullvadvpn/lib/billing/BillingRepository.kt
@@ -2,6 +2,7 @@ package net.mullvad.mullvadvpn.lib.billing
 
 import android.app.Activity
 import android.content.Context
+import co.touchlab.kermit.Logger
 import com.android.billingclient.api.BillingClient
 import com.android.billingclient.api.BillingClient.BillingResponseCode
 import com.android.billingclient.api.BillingClientStateListener
@@ -124,6 +125,11 @@ class BillingRepository(context: Context) {
         return try {
             ensureConnected()
 
+            if (obfuscatedId.isEmpty()) {
+                Logger.e("Obfuscated id is empty")
+                return BillingResult.newBuilder().setResponseCode(BillingResponseCode.ERROR).build()
+            }
+
             val productDetailsParamsList =
                 listOf(
                     BillingFlowParams.ProductDetailsParams.newBuilder()
diff --git a/android/lib/billing/src/test/kotlin/net/mullvad/mullvadvpn/lib/billing/BillingPaymentRepositoryTest.kt b/android/lib/billing/src/test/kotlin/net/mullvad/mullvadvpn/lib/billing/BillingPaymentRepositoryTest.kt
index 48618feb2b..d04c40029e 100644
--- a/android/lib/billing/src/test/kotlin/net/mullvad/mullvadvpn/lib/billing/BillingPaymentRepositoryTest.kt
+++ b/android/lib/billing/src/test/kotlin/net/mullvad/mullvadvpn/lib/billing/BillingPaymentRepositoryTest.kt
@@ -184,6 +184,32 @@ class BillingPaymentRepositoryTest {
         }
 
     @Test
+    fun `purchaseProduct should return TransactionIdError when PlayPurchasePaymentToken is empty`() =
+        runTest {
+            // Arrange
+            val mockProductId = ProductId("MOCK")
+            val mockProductDetailsResult = mockk<ProductDetailsResult>()
+            val mockProductDetails: ProductDetails = mockk()
+            every { mockProductDetails.productId } returns mockProductId.value
+            every { mockProductDetailsResult.billingResult.responseCode } returns
+                BillingResponseCode.OK
+            every { mockProductDetailsResult.productDetailsList } returns listOf(mockProductDetails)
+            coEvery { mockBillingRepository.queryProducts(listOf(mockProductId.value)) } returns
+                mockProductDetailsResult
+            coEvery { mockPlayPurchaseRepository.initializePlayPurchase() } returns
+                PlayPurchasePaymentToken("").right()
+
+            // Act, Assert
+            paymentRepository.purchaseProduct(mockProductId, mockk()).test {
+                assertIs<PurchaseResult.FetchingProducts>(awaitItem())
+                assertIs<PurchaseResult.FetchingObfuscationId>(awaitItem())
+                val result = awaitItem()
+                assertIs<PurchaseResult.Error.TransactionIdError>(result)
+                awaitComplete()
+            }
+        }
+
+    @Test
     fun `purchaseProduct should return BillingError on billing unavailable from startPurchaseFlow`() =
         runTest {
             // Arrange
diff --git a/android/lib/billing/src/test/kotlin/net/mullvad/mullvadvpn/lib/billing/BillingRepositoryTest.kt b/android/lib/billing/src/test/kotlin/net/mullvad/mullvadvpn/lib/billing/BillingRepositoryTest.kt
index 3313e2d91e..bce573a6b6 100644
--- a/android/lib/billing/src/test/kotlin/net/mullvad/mullvadvpn/lib/billing/BillingRepositoryTest.kt
+++ b/android/lib/billing/src/test/kotlin/net/mullvad/mullvadvpn/lib/billing/BillingRepositoryTest.kt
@@ -206,6 +206,27 @@ class BillingRepositoryTest {
         }
 
     @Test
+    fun `starting purchase flow with empty transaction id should return error`() = runTest {
+        // Arrange
+        val transactionId = ""
+        val mockProductDetails: ProductDetails = mockk(relaxed = true)
+        val mockActivityProvider: () -> Activity = mockk()
+        every { mockBillingClient.isReady } returns true
+        every { mockBillingClient.connectionState } returns BillingClient.ConnectionState.CONNECTED
+
+        // Act
+        val result =
+            billingRepository.startPurchaseFlow(
+                mockProductDetails,
+                transactionId,
+                mockActivityProvider,
+            )
+
+        // Assert
+        assertEquals(BillingResponseCode.ERROR, result.responseCode)
+    }
+
+    @Test
     fun `when billing client query purchases returns OK query purchases should return OK`() =
         runTest {
             // Arrange