sync: a device with no browser no longer strands the flow

Both launches can fail, and the outer catch named only
ActivityNotFoundException — so a SecurityException from a locked-down
profile escaped the LaunchedEffect and took the app down. The failure
was also ignored: onBrowserLaunched cleared openInBrowser regardless, so
the user sat on "waiting for your browser" with a spinner and no browser
for the rest of the twenty-minute window, on exactly the AOSP and
GrapheneOS devices the Custom Tabs fallback exists for.

A failed launch now says so, and the step offers the password path,
which is the only way forward on such a device.

app/src/main/java/de/jeanlucmakiola/agendula/ui/accounts/AddAccountMessage.kt

@@ -42,6 +42,9 @@ sealed interface AddAccountMessage {
     data object BrowserMaintenance : Problem
     data object BrowserFailed : Problem
 
+    /** No browser could be opened at all — AOSP, GrapheneOS, a locked-down profile. */
+    data object BrowserUnavailable : Problem
+
     /**
      * A home set on a host the credential is not scoped to.
      *

app/src/main/java/de/jeanlucmakiola/agendula/ui/accounts/AddAccountScreen.kt

@@ -1,6 +1,5 @@
 package de.jeanlucmakiola.agendula.ui.accounts
 
-import android.content.ActivityNotFoundException
 import android.content.Intent
 import androidx.browser.customtabs.CustomTabsIntent
 import androidx.compose.foundation.layout.Arrangement
@@ -96,12 +95,19 @@ internal fun AddAccountScreen(
     LaunchedEffect(state.openInBrowser) {
         val url = state.openInBrowser ?: return@LaunchedEffect
         val uri = url.toString().toUri()
-        try {
+        // ⚠️ Neither failure may escape, and neither may be ignored. An
+        // exception out of a LaunchedEffect takes the app down — and the outer
+        // catch named only ActivityNotFoundException, so a SecurityException
+        // from a locked-down profile did exactly that. Reporting the failure is
+        // the other half: clearing openInBrowser regardless left the user on
+        // "waiting for your browser" with a spinner and no browser, on the very
+        // devices this fallback exists for.
+        val launched = runCatching {
             CustomTabsIntent.Builder().build().launchUrl(context, uri)
-        } catch (_: ActivityNotFoundException) {
-            runCatching { context.startActivity(Intent(Intent.ACTION_VIEW, uri)) }
-        }
-        viewModel.onBrowserLaunched()
+        }.recoverCatching {
+            context.startActivity(Intent(Intent.ACTION_VIEW, uri))
+        }.isSuccess
+        if (launched) viewModel.onBrowserLaunched() else viewModel.onBrowserUnavailable()
     }
 
     // Backing out abandons a flow that may still be polling the server every two
@@ -349,6 +355,8 @@ private fun AddAccountMessage.text(): String = when (this) {
         stringResource(R.string.add_account_browser_error_maintenance)
     AddAccountMessage.BrowserFailed ->
         stringResource(R.string.add_account_browser_error_failed)
+    AddAccountMessage.BrowserUnavailable ->
+        stringResource(R.string.add_account_browser_error_unavailable)
     is AddAccountMessage.OutsideCredentialScope ->
         stringResource(R.string.add_account_error_cross_domain, host)
     is AddAccountMessage.Quirk -> when (quirk) {

app/src/main/java/de/jeanlucmakiola/agendula/ui/accounts/AddAccountViewModel.kt

@@ -392,6 +392,21 @@ class AddAccountViewModel @Inject constructor(
 
     fun onBrowserLaunched() = _state.update { it.copy(openInBrowser = null) }
 
+    /**
+     * Nothing could open the URL, so there is no approval coming.
+     *
+     * ⚠️ Without this, a failed launch still cleared `openInBrowser` and left the
+     * user watching "waiting for your browser" for the rest of a twenty-minute
+     * window, on exactly the browserless devices the Custom Tabs fallback exists
+     * for. Nothing was minted — the flow was never opened — so there is nothing
+     * to hand back; the poll is stopped because it is polling for an approval
+     * that cannot happen.
+     */
+    fun onBrowserUnavailable() {
+        pollJob?.cancel()
+        browserFailed(AddAccountMessage.BrowserUnavailable)
+    }
+
     fun onListToggled(url: HttpUrl) {
         val step = _state.value.step as? AddAccountStep.ChooseLists ?: return
         val selected = if (url in step.selected) step.selected - url else step.selected + url

app/src/main/res/values/strings.xml

@@ -348,6 +348,7 @@
     <string name="add_account_browser_error_rate_limited">The server is turning away repeated attempts. Wait a few minutes and try again.</string>
     <string name="add_account_browser_error_maintenance">The server is in maintenance mode. Try again once it is back.</string>
     <string name="add_account_browser_error_failed">The server didn\u2019t finish signing you in. Try again in a moment.</string>
+    <string name="add_account_browser_error_unavailable">This device has no browser that can open the sign-in page. Use a password instead.</string>
     <string name="add_account_quirk_hint_fastmail">Fastmail needs an app password, not your account password \u2014 and CalDAV is not on the Basic plan.</string>
     <string name="add_account_quirk_hint_icloud">iCloud needs an app-specific password, which you create at appleid.apple.com with two-factor on.</string>
     <string name="add_account_quirk_fastmail">Fastmail needs an app password, and CalDAV is not available on the Basic plan.</string>