fix(multiplayer): repair allocated compose verification

server/migrations/runner.go

@@ -15,6 +15,32 @@ const migrationTableSQL = `CREATE TABLE IF NOT EXISTS schema_migrations (
     applied_at TIMESTAMPTZ NOT NULL DEFAULT now()
 )`
 
+const migrationLockSQL = `SELECT pg_advisory_xact_lock(hashtext('cosmic-clash:migrations'))`
+
+// ensureMigrationTable serializes the bootstrap DDL itself. PostgreSQL's
+// CREATE TABLE IF NOT EXISTS is not safe against concurrent first creation:
+// the relation-type catalog entry can still collide before either statement
+// observes the other table. Every long-lived role calls Apply at startup, so
+// take the same transaction-scoped advisory lock used for individual files
+// before issuing the bootstrap statement.
+func ensureMigrationTable(ctx context.Context, db *sql.DB) error {
+	tx, err := db.BeginTx(ctx, nil)
+	if err != nil {
+		return fmt.Errorf("begin migration bootstrap: %w", err)
+	}
+	defer tx.Rollback()
+	if _, err := tx.ExecContext(ctx, migrationLockSQL); err != nil {
+		return fmt.Errorf("lock migration bootstrap: %w", err)
+	}
+	if _, err := tx.ExecContext(ctx, migrationTableSQL); err != nil {
+		return fmt.Errorf("create migration table: %w", err)
+	}
+	if err := tx.Commit(); err != nil {
+		return fmt.Errorf("commit migration bootstrap: %w", err)
+	}
+	return nil
+}
+
 // Apply executes numbered SQL files in lexical order. A transaction-level
 // advisory lock serializes concurrent API/worker starts, while each migration
 // is committed together with its schema_migrations marker so a failed
@@ -31,8 +57,8 @@ func Apply(ctx context.Context, db *sql.DB, directory string) error {
 	if len(paths) == 0 {
 		return fmt.Errorf("no migrations found in %s", directory)
 	}
-	if _, err := db.ExecContext(ctx, migrationTableSQL); err != nil {
-		return fmt.Errorf("create migration table: %w", err)
+	if err := ensureMigrationTable(ctx, db); err != nil {
+		return err
 	}
 	for _, path := range paths {
 		version := filepath.Base(path)
@@ -50,7 +76,7 @@ func Apply(ctx context.Context, db *sql.DB, directory string) error {
 				_ = tx.Rollback()
 			}
 		}()
-		if _, err := tx.ExecContext(ctx, `SELECT pg_advisory_xact_lock(hashtext('cosmic-clash:migrations'))`); err != nil {
+		if _, err := tx.ExecContext(ctx, migrationLockSQL); err != nil {
 			return fmt.Errorf("lock migration %s: %w", version, err)
 		}
 		var applied bool
@@ -86,8 +112,8 @@ func Rollback(ctx context.Context, db *sql.DB, directory string, steps int) erro
 	if db == nil || strings.TrimSpace(directory) == "" || steps <= 0 {
 		return fmt.Errorf("database, migration directory and a positive step count are required")
 	}
-	if _, err := db.ExecContext(ctx, migrationTableSQL); err != nil {
-		return fmt.Errorf("create migration table: %w", err)
+	if err := ensureMigrationTable(ctx, db); err != nil {
+		return err
 	}
 	rows, err := db.QueryContext(ctx, `SELECT version FROM schema_migrations ORDER BY version DESC LIMIT $1`, steps)
 	if err != nil {
@@ -123,7 +149,7 @@ func Rollback(ctx context.Context, db *sql.DB, directory string, steps int) erro
 				_ = tx.Rollback()
 			}
 		}()
-		if _, err := tx.ExecContext(ctx, `SELECT pg_advisory_xact_lock(hashtext('cosmic-clash:migrations'))`); err != nil {
+		if _, err := tx.ExecContext(ctx, migrationLockSQL); err != nil {
 			return fmt.Errorf("lock rollback %s: %w", version, err)
 		}
 		var applied bool