Crate cw2

Most of the CW* specs are focused on the public interfaces of the contract. The APIs used for ExecuteMsg or QueryMsg. However, when we wish to migrate or inspect smart contract info, we need some form of smart contract information embedded on state.

This is where CW2 comes in. It specifies a special Item to be stored on disk by all contracts on instantiate.

ContractInfo must be stored under the "contract_info" key which translates to "636F6E74726163745F696E666F" in hex format. Since the state is well defined, we do not need to support any “smart queries”. We do provide a helper to construct a “raw query” to read the ContractInfo of any CW2-compliant contract.

For more information on this specification, please check out the README.

Structs

• ContractVersion

Enums

• VersionError

Constants

• CONTRACT

Functions

• assert_contract_version
  Assert that the stored contract version info matches the given value. This is useful during migrations, for making sure that the correct contract is being migrated, and it’s being migrated from the correct version.
• ensure_from_older_version
  This function not only validates that the right contract and version can be migrated, but also updates the contract version from the original (stored) version to the new version. It returns the original version for the convenience of doing external checks.
• get_contract_version
  get_contract_version can be use in migrate to read the previous version of this contract
• query_contract_info
  This will make a raw_query to another contract to determine the current version it claims to be. This should not be trusted, but could be used as a quick filter if the other contract exists and claims to be a cw20-base contract for example. (Note: you usually want to require interfaces not implementations of the contracts you compose with, so be careful of overuse)
• set_contract_version
  set_contract_version should be used in instantiate to store the original version, and after a successful migrate to update it