Add migration test

.changeset/added_a_test_for_migrations_to_ensure_consistency_between_database_schemas.md

@@ -0,0 +1,5 @@
+---
+default: patch
+---
+
+# Added a test for migrations to ensure consistency between database schemas

persist/sqlite/init.go

@@ -34,31 +34,28 @@ func (s *Store) initNewDatabase(target int64) error {
 }
 
 func (s *Store) upgradeDatabase(current, target int64) error {
-	log := s.log.Named("migrations")
-	log.Info("migrating database", zap.Int64("current", current), zap.Int64("target", target))
-
-	return s.transaction(func(tx *txn) error {
-		// defer foreign key constraints until commit
-		if _, err := tx.Exec("PRAGMA defer_foreign_keys=ON"); err != nil {
-			return fmt.Errorf("failed to enable foreign key deferral: %w", err)
-		}
-
-		for _, fn := range migrations[current-1:] {
-			current++
-			start := time.Now()
-			if err := fn(tx, log.With(zap.Int64("version", current))); err != nil {
-				return fmt.Errorf("failed to migrate database to version %v: %w", current, err)
-			}
-			// check that no foreign key constraints were violated
-			if err := tx.QueryRow("PRAGMA foreign_key_check").Scan(); !errors.Is(err, sql.ErrNoRows) {
-				return fmt.Errorf("foreign key constraints are not satisfied")
+	log := s.log.Named("migrations").With(zap.Int64("target", target))
+	for ; current < target; current++ {
+		version := current + 1 // initial schema is version 1, migration 0 is version 2, etc.
+		log := log.With(zap.Int64("version", version))
+		start := time.Now()
+		fn := migrations[current-1]
+		err := s.transaction(func(tx *txn) error {
+			if _, err := tx.Exec("PRAGMA defer_foreign_keys=ON"); err != nil {
+				return fmt.Errorf("failed to enable foreign key deferral: %w", err)
+			} else if err := fn(tx, log); err != nil {
+				return err
+			} else if err := foreignKeyCheck(tx, log); err != nil {
+				return fmt.Errorf("failed foreign key check: %w", err)
 			}
-			log.Debug("migration complete", zap.Int64("current", current), zap.Int64("target", target), zap.Duration("elapsed", time.Since(start)))
+			return setDBVersion(tx, version)
+		})
+		if err != nil {
+			return fmt.Errorf("migration %d failed: %w", version, err)
 		}
-
-		// set the final database version
-		return setDBVersion(tx, target)
-	})
+		log.Info("migration complete", zap.Duration("elapsed", time.Since(start)))
+	}
+	return nil
 }
 
 func (s *Store) init() error {
@@ -77,3 +74,30 @@ func (s *Store) init() error {
 	// nothing to do
 	return nil
 }
+
+func foreignKeyCheck(txn *txn, log *zap.Logger) error {
+	rows, err := txn.Query("PRAGMA foreign_key_check")
+	if err != nil {
+		return fmt.Errorf("failed to run foreign key check: %w", err)
+	}
+	defer rows.Close()
+	var hasErrors bool
+	for rows.Next() {
+		var table string
+		var rowid sql.NullInt64
+		var fkTable string
+		var fkRowid sql.NullInt64
+
+		if err := rows.Scan(&table, &rowid, &fkTable, &fkRowid); err != nil {
+			return fmt.Errorf("failed to scan foreign key check result: %w", err)
+		}
+		hasErrors = true
+		log.Error("foreign key constraint violated", zap.String("table", table), zap.Int64("rowid", rowid.Int64), zap.String("fkTable", fkTable), zap.Int64("fkRowid", fkRowid.Int64))
+	}
+	if err := rows.Err(); err != nil {
+		return fmt.Errorf("failed to iterate foreign key check results: %w", err)
+	} else if hasErrors {
+		return errors.New("foreign key constraint violated")
+	}
+	return nil
+}