fix: database migration 89 needs to be 91 to allow 90 being applied first

This adds safety checks for versions that already applied migration 89.

Author: wmontwe

legacy/storage/src/main/java/com/fsck/k9/storage/migrations/MigrationTo89.kt

@@ -0,0 +1,42 @@
+package com.fsck.k9.storage.migrations
+
+import android.database.sqlite.SQLiteDatabase
+import com.fsck.k9.mailstore.MigrationsHelper
+
+/**
+ * Migration to version 91. Was planed as version 89 but got skipped, to do 90 first
+ *
+ * Adds the `account_id` column to the `folders` and `messages` tables.
+ */
+internal class MigrationTo91(private val db: SQLiteDatabase, private val migrationsHelper: MigrationsHelper) {
+
+    fun columnExists(tableName: String, columnName: String): Boolean {
+        val cursor = db.rawQuery("PRAGMA table_info($tableName)", null)
+        cursor.use {
+            while (it.moveToNext()) {
+                val currentColumnName = it.getString(it.getColumnIndexOrThrow("name"))
+                if (currentColumnName == columnName) {
+                    return true
+                }
+            }
+        }
+        return false
+    }
+
+    fun addAccountIdColumn() {
+        if (!columnExists("folders", "account_id")) {
+            db.execSQL("ALTER TABLE folders ADD account_id TEXT")
+        }
+
+        if (!columnExists("messages", "account_id")) {
+            db.execSQL("ALTER TABLE messages ADD account_id TEXT")
+        }
+
+        val accountUuid = migrationsHelper.account.uuid
+        db.execSQL("UPDATE messages SET account_id = ?", arrayOf(accountUuid))
+        db.execSQL("UPDATE folders SET account_id = ?", arrayOf(accountUuid))
+
+        db.execSQL("CREATE INDEX IF NOT EXISTS folders_account_id ON folders(account_id)")
+        db.execSQL("CREATE INDEX IF NOT EXISTS messages_account_id ON messages(account_id)")
+    }
+}

legacy/storage/src/main/java/com/fsck/k9/storage/migrations/MigrationTo91.kt

@@ -35,7 +35,7 @@ object Migrations {
         if (oldVersion < 86) MigrationTo86(db, migrationsHelper).addFoldersPushEnabledColumn()
         if (oldVersion < 87) MigrationTo87(db, migrationsHelper).addFoldersSyncEnabledColumn()
         if (oldVersion < 88) MigrationTo88(db, migrationsHelper).addFoldersVisibleColumn()
-        if (oldVersion < 89) MigrationTo89(db, migrationsHelper).addAccountIdColumn()
         if (oldVersion < 90) MigrationTo90(db, migrationsHelper).removeImapPrefixFromFolderServerId()
+        if (oldVersion < 91) MigrationTo91(db, migrationsHelper).addAccountIdColumn()
     }
 }

legacy/storage/src/main/java/com/fsck/k9/storage/migrations/Migrations.kt

@@ -18,11 +18,11 @@ import org.mockito.kotlin.mock
 import org.robolectric.RobolectricTestRunner
 
 @RunWith(RobolectricTestRunner::class)
-class MigrationTo89Test {
+class MigrationTo91Test {
     private val database = createDatabaseVersion88()
     private val account = createAccount()
     private val migrationHelper = createMigrationsHelper(account)
-    private val migration = MigrationTo89(database, migrationHelper)
+    private val migration = MigrationTo91(database, migrationHelper)
 
     @After
     fun tearDown() {
@@ -50,6 +50,24 @@ class MigrationTo89Test {
         assertThat(messages[0].accountId).isEqualTo(ACCOUNT_UUID)
     }
 
+    @Test
+    fun `should not fail if account_id column already exists`() {
+        // Arrange
+        migration.addAccountIdColumn()
+
+        // Act
+        migration.addAccountIdColumn()
+
+        // Assert
+        val folders = database.readFolders()
+        assertThat(folders).isNotNull()
+        assertThat(folders.size).isEqualTo(0)
+
+        val messages = database.readMessages()
+        assertThat(messages).isNotNull()
+        assertThat(messages.size).isEqualTo(0)
+    }
+
     private fun createAccount(): LegacyAccountDto {
         return mock {
             on { uuid } doReturn ACCOUNT_UUID