What causes "mysql dsn is nil" in iflytek/astron-agent?

In buildMysql, check the error from mysql.ParseDSN before using the returned config and return the parse error instead of continuing.

iflytek/astron-agent · error

mysql dsn is nil

Error message

mysql dsn is nil

What it means

ensureMySQLDatabase receives the parsed go-sql-driver *mysql.Config and guards against a nil pointer before it clones the DSN to run admin (database-creating) statements. A nil parsedDsn means the DSN parse step upstream produced no config object at all, so the function cannot proceed.

Solutions

In buildMysql, check the error from mysql.ParseDSN before using the returned config and return the parse error instead of continuing.
Ensure the DSN string built in parseMysqlConfig is non-empty and well-formed before parsing.
Add a defensive nil check/log where the *mysql.Config originates so the nil never propagates.
Write a unit test for buildMysql covering the empty-DSN path.

Example fix

// before
parsedDsn, _ := mysql.ParseDSN(dsn)
if err := ensureMySQLDatabase(parsedDsn); err != nil {
    return nil, err
}

// after
parsedDsn, err := mysql.ParseDSN(dsn)
if err != nil {
    return nil, fmt.Errorf("parse mysql dsn: %w", err)
}
if err := ensureMySQLDatabase(parsedDsn); err != nil {
    return nil, err
}

Defensive patterns

Strategy: type-guard

Validate before calling

if parsedDsn == nil {
	return errors.New("mysql dsn parse failed before ensureMySQLDatabase")
}

Type guard

func dsnConfigIsValid(c *mysql.Config) bool { return c != nil && c.DBName != "" }

Try / catch

if err != nil {
	return fmt.Errorf("build mysql: %w", err)
}

Prevention

Never discard errors from mysql.ParseDSN with _.
Run go vet / errcheck so ignored errors are caught in CI.
Write table-driven tests for DSN construction covering empty inputs.

When it happens

Trigger: buildMysql calls ensureMySQLDatabase with the result of mysql.ParseDSN when that call returned nil (typically alongside a parse error that was mishandled or an empty DSN input).

Common situations: Programmer error where the ParseDSN error is ignored and nil is passed through; refactoring that changed the DSN construction and dropped the error check; calling ensureMySQLDatabase directly in tests with no config.

Related errors

AI-assisted analysis of iflytek/astron-agent@5e758547a8 (2026-09-12). Data as JSON: /api/errors/487a23974615d218. Report an issue: GitHub.

Appendix: source

Thrown at core/tenant/tools/database/database.go:114

	credentials config.TenantBootstrapCredentials,
) error {
	if err := runMigrations(client); err != nil {
		return err
	}
	if err := reconcileTenantBootstrap(client, credentials); err != nil {
		return err
	}
	log.Printf("tenant bootstrap credentials reconciled")
	return nil
}

func (db *Database) GetMysql() *sql.DB {
	return db.mysql
}

func ensureMySQLDatabase(parsedDsn *mysql.Config) error {
	if parsedDsn == nil {
		return errors.New("mysql dsn is nil")
	}
	if parsedDsn.DBName == "" {
		return errors.New("mysql database name is empty")
	}

	adminDsn := parsedDsn.Clone()
	dbName := adminDsn.DBName
	adminDsn.DBName = ""

	client, err := sql.Open("mysql", adminDsn.FormatDSN())
	if err != nil {
		return err
	}
	defer func() {
		_ = client.Close()
	}()

	if err := client.Ping(); err != nil {

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