pwltr · Oct 9, 2026
diff --git a/app/src/androidTest/java/to/bitkit/services/Bip21DecodingTest.kt b/app/src/androidTest/java/to/bitkit/services/Bip21DecodingTest.kt
@@ -0,0 +1,54 @@
+package to.bitkit.services
+
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import com.synonym.bitkitcore.Scanner
+import com.synonym.bitkitcore.decode
+import org.junit.Test
+import org.junit.runner.RunWith
+import to.bitkit.ext.runSuspendCatching
+import to.bitkit.test.BaseAndroidTest
+import to.bitkit.test.annotations.CoreServiceIntegration
+import to.bitkit.test.annotations.DeviceIntegration
+import kotlin.test.assertEquals
+import kotlin.test.assertIs
+import kotlin.test.assertTrue
+
+@RunWith(AndroidJUnit4::class)
+@DeviceIntegration
+@CoreServiceIntegration
+class Bip21DecodingTest : BaseAndroidTest() {
+    companion object {
+        /** Valid regtest recipient from the bitkit-core regression fixture. */
+        private const val ADDRESS = "bcrt1qr289x0fhg62672e8urudfnxnsr8tcax64xk2vk"
+    }
+
+    @Test
+    fun coreRejectsDuplicateSingletonParameters() = test {
+        val duplicatedUri = "bitcoin:$ADDRESS?amount=0.0000002&message=Bitkit" +
+            "bitcoin:$ADDRESS?amount=0.0000003&message=Bitkit"
+        for (uri in listOf(
+            duplicatedUri,
+            "bitcoin:$ADDRESS?amount=0.000035&AMOUNT=0.00005",
+            "bitcoin:$ADDRESS?label=first&LABEL=second",
+            "bitcoin:$ADDRESS?message=first&Message=second",
+            "bitcoin:$ADDRESS?pop=callback%3a&req-pop=callback%3a",
+        )) {
+            assertTrue(runSuspendCatching { decode(uri) }.isFailure, uri)
+        }
+    }
+
+    @Test
+    fun corePreservesBitcoinTextInQueryMetadata() = test {
+        for ((key, value) in listOf(
+            "message" to "bitcoin:donation",
+            "label" to "BITCOIN:donation",
+            "custom" to "bitcoin:1BoatSLRHtKNngkdXEeobR76b53LETtpyT",
+            "message" to "Why?",
+        )) {
+            val decoded = assertIs<Scanner.OnChain>(decode("bitcoin:$ADDRESS?amount=0.000035&$key=$value"))
+            assertEquals(ADDRESS, decoded.invoice.address)
+            assertEquals(3500uL, decoded.invoice.amountSatoshis)
+            assertEquals(value, decoded.invoice.params?.get(key))
+        }
+    }
+}
diff --git a/app/src/main/java/to/bitkit/utils/Bip21Utils.kt b/app/src/main/java/to/bitkit/utils/Bip21Utils.kt
@@ -4,22 +4,6 @@ import to.bitkit.models.SATS_IN_BTC
 
 object Bip21Utils {
 
-    private const val BIP21_PREFIX = "bitcoin:"
-
-    /**
-     * Checks if a BIP21 URI is duplicated (contains multiple bitcoin: prefixes).
-     * Workaround for https://github.com/synonymdev/bitkit-core/issues/63
-     * @return true if the input contains duplicated BIP21 URIs, false otherwise
-     */
-    fun isDuplicatedBip21(input: String): Boolean {
-        val lowercased = input.lowercase()
-        val firstIndex = lowercased.indexOf(BIP21_PREFIX)
-        if (firstIndex == -1) return false
-
-        val secondIndex = lowercased.indexOf(BIP21_PREFIX, firstIndex + BIP21_PREFIX.length)
-        return secondIndex != -1
-    }
-
     fun buildBip21Url(
         bitcoinAddress: String,
         amountSats: ULong? = null,

diff --git a/app/src/main/java/to/bitkit/viewmodels/AppViewModel.kt b/app/src/main/java/to/bitkit/viewmodels/AppViewModel.kt
@@ -208,7 +208,6 @@ import to.bitkit.ui.utils.localizedPubkyAuthMessage
 import to.bitkit.usecases.FormatMoneyValue
 import to.bitkit.usecases.RefreshContactPaykitLinkUseCase
 import to.bitkit.utils.AppError
-import to.bitkit.utils.Bip21Utils
 import to.bitkit.utils.Logger
 import to.bitkit.utils.NetworkValidationHelper
 import to.bitkit.utils.ServiceError
@@ -2441,16 +2440,6 @@ class AppViewModel @Inject constructor(
     }
 
     private suspend fun validateAddressWithFeedback(input: String) = withContext(bgDispatcher) {
-        // TODO Workaround for https://github.com/synonymdev/bitkit-core/issues/63
-        if (Bip21Utils.isDuplicatedBip21(input)) {
-            showAddressValidationError(
-                titleRes = R.string.other__scan_err_decoding,
-                descriptionRes = R.string.other__scan__error__generic,
-                testTag = "DuplicatedBip21Toast",
-            )
-            return@withContext
-        }
-
         val scanResult = runCatching { coreService.decode(input.removeLightningSchemes()) }
 
         if (scanResult.isFailure) {
@@ -3361,18 +3350,6 @@ class AppViewModel @Inject constructor(
 
         val fromMainScanner = isMainScanner
 
-        // TODO Workaround for https://github.com/synonymdev/bitkit-core/issues/63
-        if (Bip21Utils.isDuplicatedBip21(input)) {
-            if (clearIncomingPaymentRequestTarget()) return@withContext
-            toast(
-                type = Toast.ToastType.ERROR,
-                title = context.getString(R.string.other__scan_err_decoding),
-                description = context.getString(R.string.other__scan__error__generic),
-                testTag = "DuplicatedBip21Toast",
-            )
-            return@withContext
-        }
-
         SamRockSetupRequest.parse(input)?.let {
             handleSamRockSetup(it)
             return@withContext

diff --git a/app/src/test/java/to/bitkit/utils/Bip21UrlBuilderTest.kt b/app/src/test/java/to/bitkit/utils/Bip21UrlBuilderTest.kt
@@ -5,7 +5,6 @@ import org.junit.Test
 import org.junit.runner.RunWith
 import org.junit.runners.JUnit4
 import to.bitkit.utils.Bip21Utils.buildBip21Url
-import to.bitkit.utils.Bip21Utils.isDuplicatedBip21
 
 @RunWith(JUnit4::class)
 class Bip21UrlBuilderTest {
@@ -173,49 +172,6 @@ class Bip21UrlBuilderTest {
         Assert.assertEquals(expected, buildBip21Url(address, amount, lightningInvoice = invoice))
     }
 
-    // Tests for isDuplicatedBip21 - Workaround for bitkit-core#63
-
-    @Test
-    fun `isDuplicatedBip21 returns false for single valid BIP21 URI`() {
-        val input = "bitcoin:bc1qar0srrr7xfkvy5l643lydnw9re59gtzzwf5mdq?amount=0.001&message=Bitkit"
-        Assert.assertFalse(isDuplicatedBip21(input))
-    }
-
-    @Test
-    fun `isDuplicatedBip21 returns true when BIP21 URI is duplicated`() {
-        val first = "bitcoin:bcrt1qr289x0fhg62672e8urudfnxnsr8tcax64xk2vk?amount=0.0000002&message=Bitkit"
-        val second = "bitcoin:bcrt1qr289x0fhg62672e8urudfnxnsr8tcax64xk2vk?amount=0.0000003&message=Bitkit"
-        val input = first + second
-        Assert.assertTrue(isDuplicatedBip21(input))
-    }
-
-    @Test
-    fun `isDuplicatedBip21 handles case-insensitive bitcoin prefix`() {
-        val first = "BITCOIN:bc1qar0srrr7xfkvy5l643lydnw9re59gtzzwf5mdq?amount=0.001"
-        val second = "bitcoin:bc1qar0srrr7xfkvy5l643lydnw9re59gtzzwf5mdq?amount=0.002"
-        val input = first + second
-        Assert.assertTrue(isDuplicatedBip21(input))
-    }
-
-    @Test
-    fun `isDuplicatedBip21 returns false for non-bitcoin URIs`() {
-        val input = "lnbc500n1p3k9v3pp5kzmj..."
-        Assert.assertFalse(isDuplicatedBip21(input))
-    }
-
-    @Test
-    fun `isDuplicatedBip21 returns false for empty string`() {
-        Assert.assertFalse(isDuplicatedBip21(""))
-    }
-
-    @Test
-    fun `isDuplicatedBip21 handles mixed case duplicated URIs`() {
-        val first = "Bitcoin:bc1qaddr1?amount=0.001"
-        val second = "BITCOIN:bc1qaddr2?amount=0.002"
-        val input = first + second
-        Assert.assertTrue(isDuplicatedBip21(input))
-    }
-
     // Tests for empty/blank message and label handling - Issue #746
 
     @Test

diff --git a/app/src/test/java/to/bitkit/viewmodels/AppViewModelSendFlowTest.kt b/app/src/test/java/to/bitkit/viewmodels/AppViewModelSendFlowTest.kt
@@ -2196,11 +2196,12 @@ class AppViewModelSendFlowTest : BaseUnitTest() {
     }
 
     @Test
-    fun `duplicated bip21 request target leaves terminal feedback visible`() = test {
+    fun `core rejected bip21 request target leaves terminal feedback visible`() = test {
         sut.setIsAuthenticated(true)
         val request = paymentRequest()
         val first = "bitcoin:bcrt1qfirst?amount=0.00000001"
         val duplicatedBip21 = first + "bitcoin:bcrt1qsecond?amount=0.00000001"
+        whenever(coreService.decode(duplicatedBip21)).doSuspendableAnswer { throw AppError("Invalid payment URI") }
         whenever(context.getString(R.string.wallet__payment_request)).thenReturn("Payment Request")
         whenever(context.getString(R.string.wallet__payment_request_waiting_for_details)).thenReturn("Waiting")
         whenever(context.getString(R.string.wallet__payment_request_unavailable)).thenReturn(
@@ -6649,6 +6650,65 @@ class AppViewModelSendFlowTest : BaseUnitTest() {
         assertEquals("InsufficientSavingsToast", toastCaptor.lastValue.testTag)
     }
 
+    @Test
+    fun `manual bip21 with bitcoin text delegates to core and stays valid`() = test {
+        val uri = "bitcoin:$REGTEST_ADDRESS?amount=0.000035&message=bitcoin:donation"
+        stubBip21Scan(uri)
+
+        sut.setSendEvent(SendEvent.AddressChange(uri))
+        advanceUntilIdle()
+
+        verify(coreService).decode(uri)
+        assertTrue(sut.sendUiState.value.isAddressInputValid)
+        assertTrue(sut.canDecodeClipboard(uri))
+    }
+
+    @Test
+    fun `manual bip21 rejected by core stays invalid`() = test {
+        val uri = "bitcoin:$REGTEST_ADDRESS?amount=0.000035&amount=0.00005"
+        whenever(coreService.decode(uri)).doSuspendableAnswer { throw AppError("Invalid payment URI") }
+        clearInvocations(toastManager)
+
+        sut.setSendEvent(SendEvent.AddressChange(uri))
+        advanceUntilIdle()
+
+        verify(coreService).decode(uri)
+        assertFalse(sut.sendUiState.value.isAddressInputValid)
+        verify(toastManager).enqueue(check { assertEquals("InvalidAddressToast", it.testTag) })
+    }
+
+    @Test
+    fun `scanned bip21 with bitcoin text reaches send state`() = test {
+        val uri = "bitcoin:$REGTEST_ADDRESS?amount=0.000035&message=bitcoin:donation"
+        stubBip21Scan(uri)
+        sut.setIsAuthenticated(true)
+
+        sut.onScanResult(uri)
+        advanceUntilIdle()
+
+        verify(coreService).decode(uri)
+        assertEquals(REGTEST_ADDRESS, sut.sendUiState.value.address)
+        assertEquals(uri, sut.sendUiState.value.addressInput)
+        assertEquals(3500uL, sut.sendUiState.value.amount)
+    }
+
+    @Test
+    fun `scanned concatenated bip21 rejected by core clears previous payment`() = test {
+        val first = "bitcoin:$REGTEST_ADDRESS?amount=0.000035&message=Bitkit"
+        val uri = first + "bitcoin:$REGTEST_ADDRESS?amount=0.00005&message=Bitkit"
+        whenever(coreService.decode(uri)).doSuspendableAnswer { throw AppError("Invalid payment URI") }
+        setSendState(SendUiState(address = REGTEST_ADDRESS, amount = 3500uL))
+        sut.setIsAuthenticated(true)
+
+        sut.onScanResult(uri)
+        advanceUntilIdle()
+
+        verify(coreService).decode(uri)
+        assertEquals("", sut.sendUiState.value.address)
+        assertEquals(0uL, sut.sendUiState.value.amount)
+        assertNull(sut.currentSheet.value)
+    }
+
     @Test
     fun `manual input of unified own lightning invoice with no savings shows self payment toast`() = test {
         val bolt11 = "lnbcrt1ownunifiedmanual"
@@ -10326,6 +10386,28 @@ class AppViewModelSendFlowTest : BaseUnitTest() {
         stubLightningScan(bolt11 = bolt11, amountSats = amountSats, payeeNodeId = payeeNodeId)
     }
 
+    private suspend fun stubBip21Scan(uri: String) {
+        balanceState.value = BalanceState(maxSendOnchainSats = 100_000uL)
+        whenever { coreService.decode(uri) }.thenReturn(
+            Scanner.OnChain(
+                OnChainInvoice(
+                    address = REGTEST_ADDRESS,
+                    amountSatoshis = 3500uL,
+                    label = null,
+                    message = "bitcoin:donation",
+                    params = mapOf("message" to "bitcoin:donation"),
+                )
+            )
+        )
+        whenever(coreService.validateBitcoinAddress(REGTEST_ADDRESS)).thenReturn(
+            ValidationResult(
+                address = REGTEST_ADDRESS,
+                network = NetworkType.REGTEST,
+                addressType = AddressType.P2WPKH,
+            )
+        )
+    }
+
     private fun nonOnchainPaymentScans() = listOf(
         "lnbcrt1hardware" to Scanner.Lightning(lightningInvoice("lnbcrt1hardware", 1_000uL)),
         "lnurl1hardware" to Scanner.LnurlPay(

diff --git a/changelog.d/next/1454.fixed.md b/changelog.d/next/1454.fixed.md
@@ -0,0 +1 @@
+Fixed payment URI validation to accept Bitcoin links in notes while rejecting ambiguous payment requests through the shared decoder.
diff --git a/journeys/send/README.md b/journeys/send/README.md
@@ -0,0 +1,11 @@
+# Send
+
+`bip21-core-validation.xml` is shared with iOS, with identical actions and fixtures. It requires a released bitkit-core SDK containing [PR #151](https://github.com/synonymdev/bitkit-core/pull/151); the current 0.5.18 dependency cannot satisfy its duplicate-key checks. Keep the adoption PR in draft until that dependency is bumped and the journey passes.
+
+Deliver each `Open bitcoin:...` action with `adb shell "am start -a android.intent.action.VIEW -d '<uri>' to.bitkit.dev"`, replacing XML `&amp;` with `&` in the actual URI. Inspect errors immediately. Use `android layout` for payment state and screenshots for transient error toasts, which the semantic dump does not expose.
+
+Use an onboarded regtest wallet with at least 100,000 sats in Savings and Quickpay disabled. The fixture address is not a destination to pay; close every payment sheet without confirming payment.
+
+The native-binding tests also cover labels, proof-of-payment aliases and question marks in notes. App tests cover manual entry and payment-request failure handling. Automatic clipboard prompting additionally has a manual check because arbitrary OS clipboard injection is not listed in the Capabilities table. Do not type long URI fixtures with `adb shell input text`, which can truncate them.
+
+`own-invoice-guard.xml` covers the existing Lightning self-payment guard and is unchanged by this adoption.
diff --git a/journeys/send/bip21-core-validation.xml b/journeys/send/bip21-core-validation.xml
@@ -0,0 +1,17 @@
+<journey name="bip21 core validation">
+  <description>Preconditions: an onboarded English-language regtest wallet with at least 100,000 sats in Savings, Quickpay disabled, and a bitkit-core release containing PR #151. Do not pay any fixture. Open each bitcoin: link through the platform's external-URI delivery command described in this suite's README. This checks that the native decoder rejects ambiguous payments while accepting bitcoin: text as metadata.</description>
+  <actions>
+    <action>Open bitcoin:bcrt1qr289x0fhg62672e8urudfnxnsr8tcax64xk2vk?amount=0.000035&amp;message=bitcoin:donation</action>
+    <action>Verify Send shows the recipient bcrt1qr289x0fhg62672e8urudfnxnsr8tcax64xk2vk, an amount of 3,500 sats, and the note bitcoin:donation without a decoding error</action>
+    <action>Close Send without paying</action>
+    <action>Open bitcoin:bcrt1qr289x0fhg62672e8urudfnxnsr8tcax64xk2vk?amount=0.0000002&amp;message=Bitkitbitcoin:bcrt1qr289x0fhg62672e8urudfnxnsr8tcax64xk2vk?amount=0.0000003&amp;message=Bitkit</action>
+    <action>Verify a decoding error appears and Send does not open with the previous payment</action>
+    <action>Open bitcoin:bcrt1qr289x0fhg62672e8urudfnxnsr8tcax64xk2vk?amount=0.000035&amp;AMOUNT=0.00005</action>
+    <action>Verify a decoding error appears and no payment sheet opens</action>
+    <action>Open bitcoin:bcrt1qr289x0fhg62672e8urudfnxnsr8tcax64xk2vk?message=first&amp;Message=second</action>
+    <action>Verify a decoding error appears and no payment sheet opens</action>
+    <action>Open bitcoin:bcrt1qr289x0fhg62672e8urudfnxnsr8tcax64xk2vk?amount=0.000035&amp;custom=bitcoin:1BoatSLRHtKNngkdXEeobR76b53LETtpyT</action>
+    <action>Verify Send still shows bcrt1qr289x0fhg62672e8urudfnxnsr8tcax64xk2vk as the recipient and 3,500 sats as the amount</action>
+    <action>Close Send without paying</action>
+  </actions>
+</journey>
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1 @@
		Fixed payment URI validation to accept Bitcoin links in notes while rejecting ambiguous payment requests through the shared decoder.