Don't let a prefilled account ID suppress the password manager prompt.

feature/registration/src/main/java/org/signal/registration/screens/signallogincredentials/SignalLoginCredentialEntryScreen.kt

@@ -252,8 +252,8 @@ private fun CredentialTextFields(
 
 /**
  * Builds a modifier that prompts the password manager the first time either credential field is tapped, so a saved
- * login can fill both halves at once. Only fires while the fields are still empty, and only once per screen so a
- * dismissed prompt doesn't keep coming back.
+ * login can fill both halves at once. Only fires while the user hasn't filled anything in themselves, and only once
+ * per screen so a dismissed prompt doesn't keep coming back.
  */
 @Composable
 private fun passwordManagerPromptOnFocus(
@@ -265,8 +265,7 @@ private fun passwordManagerPromptOnFocus(
   var hasPrompted by rememberSaveable { mutableStateOf(false) }
 
   return Modifier.onFocusChanged { focusState ->
-    val fieldsAreEmpty = state.accountId.isEmpty() && state.recoveryKey.enteredText.isEmpty()
-    if (focusState.isFocused && !hasPrompted && fieldsAreEmpty && SignalCredentialManager.isSupported(context)) {
+    if (focusState.isFocused && !hasPrompted && state.canPromptPasswordManager && SignalCredentialManager.isSupported(context)) {
       hasPrompted = true
       coroutineScope.launch {
         val credential = SignalCredentialManager.getCredential(context)

feature/registration/src/main/java/org/signal/registration/screens/signallogincredentials/SignalLoginCredentialEntryState.kt

@@ -20,6 +20,8 @@ import org.signal.registration.screens.shared.AccountIdFormat
 data class SignalLoginCredentialEntryState(
   val accountId: String = "",
   val accountIdError: AccountIdError? = null,
+  /** Whether [accountId] was handed to the screen by the flow rather than typed by the user, and so isn't user input. */
+  val isAccountIdPrefilled: Boolean = false,
   val recoveryKey: AepInput = AepInput(),
   /** Whether the recovery key is spelled out rather than masked like a password. */
   val isRecoveryKeyRevealed: Boolean = false,
@@ -38,7 +40,11 @@ data class SignalLoginCredentialEntryState(
       !areCredentialsIncorrect &&
       !isLoggingIn
 
-  override fun toString(): String = "SignalLoginCredentialEntryState(accountId=${accountId.censor()}, accountIdError=$accountIdError, recoveryKey=$recoveryKey, isRecoveryKeyRevealed=$isRecoveryKeyRevealed, areCredentialsIncorrect=$areCredentialsIncorrect, isLoggingIn=$isLoggingIn, loginError=$loginError)"
+  /** Allow prompting if it's empty or came pre-filled */
+  val canPromptPasswordManager: Boolean
+    get() = recoveryKey.enteredText.isEmpty() && (accountId.isEmpty() || isAccountIdPrefilled)
+
+  override fun toString(): String = "SignalLoginCredentialEntryState(accountId=${accountId.censor()}, accountIdError=$accountIdError, isAccountIdPrefilled=$isAccountIdPrefilled, recoveryKey=$recoveryKey, isRecoveryKeyRevealed=$isRecoveryKeyRevealed, areCredentialsIncorrect=$areCredentialsIncorrect, isLoggingIn=$isLoggingIn, loginError=$loginError)"
 }
 
 /** A login failure that the text fields can't express, so it gets a dialog instead. */

feature/registration/src/main/java/org/signal/registration/screens/signallogincredentials/SignalLoginCredentialEntryViewModel.kt

@@ -49,7 +49,12 @@ class SignalLoginCredentialEntryViewModel(
     private val TAG = Log.tag(SignalLoginCredentialEntryViewModel::class)
   }
 
-  private val _state = MutableStateFlow(SignalLoginCredentialEntryState(accountId = prefilledAccountId ?: ""))
+  private val _state = MutableStateFlow(
+    SignalLoginCredentialEntryState(
+      accountId = prefilledAccountId ?: "",
+      isAccountIdPrefilled = !prefilledAccountId.isNullOrEmpty()
+    )
+  )
   val state: StateFlow<SignalLoginCredentialEntryState> = _state.asStateFlow()
 
   private val _actions = Channel<SignalLoginCredentialEntryScreenActions>(Channel.BUFFERED)
@@ -79,7 +84,7 @@ class SignalLoginCredentialEntryViewModel(
 
       is SignalLoginCredentialEntryScreenEvents.AccountIdChanged -> {
         val accountId = AccountIdFormat.normalize(event.value)
-        stateEmitter(state.copy(accountId = accountId, accountIdError = AccountIdFormat.validate(accountId), areCredentialsIncorrect = false))
+        stateEmitter(state.copy(accountId = accountId, accountIdError = AccountIdFormat.validate(accountId), isAccountIdPrefilled = false, areCredentialsIncorrect = false))
       }
 
       is SignalLoginCredentialEntryScreenEvents.RecoveryKeyChanged -> {
@@ -126,10 +131,11 @@ class SignalLoginCredentialEntryViewModel(
     parentEventEmitter: (RegistrationFlowEvent) -> Unit,
     stateEmitter: (SignalLoginCredentialEntryState) -> Unit
   ) {
-    val accountId = AccountIdFormat.normalize(event.accountId)
+    val accountId = AccountIdFormat.normalize(event.accountId).ifEmpty { state.accountId }
     val filledState = state.copy(
       accountId = accountId,
       accountIdError = AccountIdFormat.validate(accountId),
+      isAccountIdPrefilled = false,
       recoveryKey = AepInput.from(event.recoveryKey),
       areCredentialsIncorrect = false
     )

feature/registration/src/test/java/org/signal/registration/screens/signallogincredentials/SignalLoginCredentialEntryScreenTest.kt

@@ -83,6 +83,28 @@ class SignalLoginCredentialEntryScreenTest {
     coVerify(exactly = 0) { SignalCredentialManager.getCredential(any()) }
   }
 
+  @Test
+  fun `when a field is tapped with only a prefilled account ID, the password manager is still prompted`() {
+    stubPasswordManager()
+    setContent(SignalLoginCredentialEntryState(accountId = VALID_ACCOUNT_ID, isAccountIdPrefilled = true))
+
+    composeTestRule.onNodeWithTag(TestTags.SIGNAL_LOGIN_CREDENTIAL_ACCOUNT_ID_FIELD).performClick()
+    composeTestRule.waitForIdle()
+
+    assertThat(events).contains(SignalLoginCredentialEntryScreenEvents.PasswordManagerCredentialSelected(accountId = VALID_ACCOUNT_ID, recoveryKey = VALID_RECOVERY_KEY))
+  }
+
+  @Test
+  fun `when a field is tapped with a user-typed account ID, the password manager is not prompted`() {
+    stubPasswordManager()
+    setContent(SignalLoginCredentialEntryState(accountId = VALID_ACCOUNT_ID))
+
+    composeTestRule.onNodeWithTag(TestTags.SIGNAL_LOGIN_CREDENTIAL_ACCOUNT_ID_FIELD).performClick()
+    composeTestRule.waitForIdle()
+
+    coVerify(exactly = 0) { SignalCredentialManager.getCredential(any()) }
+  }
+
   @Test
   fun `the account ID field is tagged for autofill as the username`() {
     setContent(SignalLoginCredentialEntryState())

feature/registration/src/test/java/org/signal/registration/screens/signallogincredentials/SignalLoginCredentialEntryViewModelTest.kt

@@ -95,6 +95,41 @@ class SignalLoginCredentialEntryViewModelTest {
     assertThat(prefilled.state.value.accountId).isEqualTo(VALID_ACCOUNT_ID)
   }
 
+  @Test
+  fun `a prefilled account ID does not count as user input, so the password manager can still be offered`() = runTest(testDispatcher) {
+    val prefilled = SignalLoginCredentialEntryViewModel(repository = mockRepository, parentEventEmitter = parentEventEmitter, prefilledAccountId = VALID_ACCOUNT_ID)
+
+    assertThat(prefilled.state.value.isAccountIdPrefilled).isTrue()
+    assertThat(prefilled.state.value.canPromptPasswordManager).isTrue()
+  }
+
+  @Test
+  fun `without a prefilled account ID the screen starts empty and the password manager can be offered`() = runTest(testDispatcher) {
+    assertThat(viewModel.state.value.isAccountIdPrefilled).isFalse()
+    assertThat(viewModel.state.value.canPromptPasswordManager).isTrue()
+  }
+
+  @Test
+  fun `an account ID the user typed themselves stops the password manager from being offered`() = runTest(testDispatcher) {
+    applyEvent(
+      SignalLoginCredentialEntryState(accountId = VALID_ACCOUNT_ID, isAccountIdPrefilled = true),
+      SignalLoginCredentialEntryScreenEvents.AccountIdChanged("a6b28482")
+    )
+
+    assertThat(emittedStates.last().isAccountIdPrefilled).isFalse()
+    assertThat(emittedStates.last().canPromptPasswordManager).isFalse()
+  }
+
+  @Test
+  fun `an entered recovery key stops the password manager from being offered`() = runTest(testDispatcher) {
+    applyEvent(
+      SignalLoginCredentialEntryState(accountId = VALID_ACCOUNT_ID, isAccountIdPrefilled = true),
+      SignalLoginCredentialEntryScreenEvents.RecoveryKeyChanged("uy38")
+    )
+
+    assertThat(emittedStates.last().canPromptPasswordManager).isFalse()
+  }
+
   @Test
   fun `BackClicked navigates back`() = runTest(testDispatcher) {
     applyEvent(SignalLoginCredentialEntryState(), SignalLoginCredentialEntryScreenEvents.BackClicked)
@@ -191,6 +226,19 @@ class SignalLoginCredentialEntryViewModelTest {
     coVerify(exactly = 0) { mockRepository.reRegisterAccountWithoutPhoneNumber(any(), any(), any(), any(), any()) }
   }
 
+  @Test
+  fun `PasswordManagerCredentialSelected keeps a prefilled account ID when the credential has no username`() = runTest(testDispatcher) {
+    stubSuccessfulLogin(AccountEntropyPool(VALID_AEP))
+
+    applyEvent(
+      SignalLoginCredentialEntryState(accountId = VALID_ACCOUNT_ID, isAccountIdPrefilled = true),
+      SignalLoginCredentialEntryScreenEvents.PasswordManagerCredentialSelected(accountId = "", recoveryKey = VALID_AEP)
+    )
+
+    assertThat(emittedStates.first().accountId).isEqualTo(VALID_ACCOUNT_ID)
+    coVerify { mockRepository.reRegisterAccountWithoutPhoneNumber(any(), any(), any(), any(), any()) }
+  }
+
   @Test
   fun `PasswordManagerCredentialSelected clears a previously rejected login`() = runTest(testDispatcher) {
     stubSuccessfulLogin(AccountEntropyPool(VALID_AEP))