Function updateChainConfig

core/genesis.go:182–189

(storedcfg *configs.ChainConfig, newcfg *configs.ChainConfig, db database.Database, stored common.Hash)

}

func updateChainConfig(storedcfg *configs.ChainConfig, newcfg *configs.ChainConfig, db database.Database, stored common.Hash) *configs.ChainConfig {
	if storedcfg == nil {
		log.Warn("Found genesis block without chain config")
	}
	// NOTICE: in future we may need to check the compatibility of old and new configurations.
	rawdb.WriteChainConfig(db, stored, newcfg)
	return newcfg
}

// OpenGenesisBlock opens genesis block and returns its chain configuration and hash.
// Return errors when genesis block not exist or genesis block configuration not exist.