sqldb: establish a base DB version even if it's not yet tracked

Previously, if a DB version wasn't available, we re-ran all schema
migrations without verifying the schema version. However, setting a
base schema version is essential because some earlier migrations were
not idempotent. This commit addresses the issue by using the current
schema version provided by sqlc as the base.

sqldb/sqlite.go

@@ -158,6 +158,10 @@ func (s *SqliteStore) ApplyAllMigrations(ctx context.Context,
 	return ApplyMigrations(ctx, s.BaseDB, s, migrations)
 }
 
+func errSqliteMigration(err error) error {
+	return fmt.Errorf("error creating sqlite migration: %w", err)
+}
+
 // ExecuteMigrations runs migrations for the sqlite database, depending on the
 // target given, either all migrations or up to a given version.
 func (s *SqliteStore) ExecuteMigrations(target MigrationTarget) error {
@@ -165,7 +169,7 @@ func (s *SqliteStore) ExecuteMigrations(target MigrationTarget) error {
 		s.DB, &sqlite_migrate.Config{},
 	)
 	if err != nil {
-		return fmt.Errorf("error creating sqlite migration: %w", err)
+		return errSqliteMigration(err)
 	}
 
 	// Populate the database with our set of schemas based on our embedded
@@ -176,6 +180,23 @@ func (s *SqliteStore) ExecuteMigrations(target MigrationTarget) error {
 	)
 }
 
+// GetSchemaVersion returns the current schema version of the SQLite database.
+func (s *SqliteStore) GetSchemaVersion() (int, bool, error) {
+	driver, err := sqlite_migrate.WithInstance(
+		s.DB, &sqlite_migrate.Config{},
+	)
+	if err != nil {
+		return 0, false, errSqliteMigration(err)
+	}
+
+	version, dirty, err := driver.Version()
+	if err != nil {
+		return 0, dirty, err
+	}
+
+	return version, dirty, nil
+}
+
 // NewTestSqliteDB is a helper function that creates an SQLite database for
 // testing.
 func NewTestSqliteDB(t *testing.T) *SqliteStore {