fix: harden provider session restoration

android/core/session/src/main/kotlin/com/flagship/abox/manager/session/profile/ProviderProfileStoreImpl.kt

@@ -4,6 +4,7 @@ import androidx.datastore.core.DataStore
 import androidx.datastore.preferences.core.Preferences
 import androidx.datastore.preferences.core.booleanPreferencesKey
 import androidx.datastore.preferences.core.edit
+import androidx.datastore.preferences.core.emptyPreferences
 import androidx.datastore.preferences.core.stringPreferencesKey
 import androidx.datastore.preferences.core.stringSetPreferencesKey
 import com.flagship.abox.manager.domain.DomainResult
@@ -13,19 +14,34 @@ import com.flagship.abox.manager.domain.ProviderProfileId
 import com.flagship.abox.manager.domain.ProviderProfileStore
 import com.flagship.abox.manager.domain.ProviderType
 import com.flagship.abox.manager.domain.Username
+import java.io.IOException
+import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.catch
 import kotlinx.coroutines.flow.first
 import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.flow.retryWhen
 
 class ProviderProfileStoreImpl(
     private val dataStore: DataStore<Preferences>,
 ) : ProviderProfileStore {
-    override fun observeProfiles(): Flow<List<ProviderProfile>> = dataStore.data.map(::profilesFrom)
+    private val safeData: Flow<Preferences>
+        get() = dataStore.data
+            .retryWhen { cause, attempt ->
+                val retry = cause is IOException && attempt < MAX_READ_RETRIES
+                if (retry) delay(READ_RETRY_DELAY_MILLIS)
+                retry
+            }
+            .catch { error ->
+                if (error is IOException) emit(emptyPreferences()) else throw error
+            }
 
-    override fun observeActiveProfile(): Flow<ProviderProfile?> = dataStore.data.map(::activeProfileFrom)
+    override fun observeProfiles(): Flow<List<ProviderProfile>> = safeData.map(::profilesFrom)
+
+    override fun observeActiveProfile(): Flow<ProviderProfile?> = safeData.map(::activeProfileFrom)
 
     override fun observeLoginPreferences(profileId: ProviderProfileId): Flow<LoginPreferences> =
-        dataStore.data.map { preferencesFrom(it, profileId) }
+        safeData.map { preferencesFrom(it, profileId) }
 
     override suspend fun profiles(): List<ProviderProfile> = profilesFrom(dataStore.data.first())
 
@@ -99,6 +115,8 @@ class ProviderProfileStoreImpl(
     }
 
     companion object {
+        private const val MAX_READ_RETRIES = 2L
+        private const val READ_RETRY_DELAY_MILLIS = 50L
         private val PROFILE_IDS = stringSetPreferencesKey("profile_ids")
         private val ACTIVE_PROFILE_ID = stringPreferencesKey("active_profile_id")
 

android/core/session/src/main/kotlin/com/flagship/abox/manager/session/profile/SessionDataStore.kt

@@ -2,11 +2,14 @@ package com.flagship.abox.manager.session.profile
 
 import android.content.Context
 import androidx.datastore.core.DataStore
+import androidx.datastore.core.handlers.ReplaceFileCorruptionHandler
 import androidx.datastore.preferences.core.Preferences
+import androidx.datastore.preferences.core.emptyPreferences
 import androidx.datastore.preferences.preferencesDataStore
 
 private const val SESSION_DATA_STORE_NAME = "provider_session"
 
 val Context.sessionDataStore: DataStore<Preferences> by preferencesDataStore(
     name = SESSION_DATA_STORE_NAME,
+    corruptionHandler = ReplaceFileCorruptionHandler { emptyPreferences() },
 )

android/core/session/src/test/kotlin/com/flagship/abox/manager/session/ProviderProfileStoreFailureTest.kt

@@ -0,0 +1,33 @@
+package com.flagship.abox.manager.session
+
+import androidx.datastore.core.DataStore
+import androidx.datastore.preferences.core.Preferences
+import androidx.datastore.preferences.core.emptyPreferences
+import com.flagship.abox.manager.session.profile.ProviderProfileStoreImpl
+import java.io.IOException
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.flow.flow
+import kotlinx.coroutines.test.runTest
+import org.junit.Assert.assertEquals
+import org.junit.Test
+
+class ProviderProfileStoreFailureTest {
+    @Test
+    fun ioFailureFallsBackToEmptyPreferences() = runTest {
+        val store = ProviderProfileStoreImpl(FailingReadDataStore())
+
+        assertEquals(emptyList<Any>(), store.observeProfiles().first())
+        assertEquals(null, store.observeActiveProfile().first())
+    }
+
+    private class FailingReadDataStore : DataStore<Preferences> {
+        override val data: Flow<Preferences> = flow {
+            throw IOException("disk unavailable")
+        }
+
+        override suspend fun updateData(
+            transform: suspend (t: Preferences) -> Preferences,
+        ): Preferences = transform(emptyPreferences())
+    }
+}