Contract upgrade anti-patterns
A popular trend in smart contract design is to promote the development of upgradable contracts . To be fair, existing techniques to upgrade contracts have flaws, increase the complexity of the contract significantly, and ultimately introduce bugs - even in the Zeppelin contract upgrade strategy. In this article, we are going to detail our analysis of existing smart contract upgrade strategies, describe the weaknesses we have observed in practice, and provide recommendations for contracts that require upgrades. In a follow-up blog post, we will detail a method, contract migration, that achieves the same benefits with few of the downsides. An overview of upgradable contracts Two ‘families’ of patterns have emerged for upgradable smart contracts: Data separation, where logic and data are kept in separate contracts. The logic contract owns and calls the data contract. Delegatecall-based proxies, where logic and data are kept in separate contracts, also, but the data contr...