Recently we wrote a contract using an Upgradeable Proxy pattern (EIP173) similar to the Transparent Proxy pattern used by OpenZeppelin.
Notably we did not use the OZ SDK or CLI.
At one point we changed solidity compiler versions from
0.7 and downgraded the
@openzeppelin/contracts package from
Upon upgrading our Proxy thereafter, we noticed that the state storage values were corrupted after the upgrade. However, we hadnt changed the contracts inheritance or state layout.
The contract inherits state from OZ contracts like:
We wondered whether downgrade in the
@openzepplin/contracts version might have resulted in some of the contracts dependencies to have a different state layout than before and thus break the safety of the upgradeable layout we relied on?
Question: when using upgradeable contracts that have to stick to an append-only state layout, is it unsafe to switch versions of the @openzeppelin/contracts package in between upgrades?
Is there a granular safe way to switch between versions of the package? E.g. everything within a
major version is safe for upgrading, whereas switching in between major versions of the package is dangerous because state layout might be changed in between major versions?