[Audit Fix] Re-evaluate EternalModel

[dmvt]

The Eternal Storage pattern is not used in the way it is designed. According to https://fravoll.github.io/solidity-patterns/eternal_storage.html:
“A separate contract, with the sole purpose of acting as a storage to another contract, is introduced.”
However with ElasticDAO the contracts are derived from EternalModel and thus the EternalModel memory is integrated in the contract:
• contract TokenHolder is EternalModel, ReentryProtection {
• contract Token is EternalModel, ReentryProtection {
• contract Ecosystem is EternalModel, ReentryProtection {
• contract DAO is EternalModel, ReentryProtection {
You can also see the difference in the implementation of the EternalModel functions, they should be external to be callable from another contract:
ElasticDAO EternalModel.sol:
Fravoll EternalModel.sol:
function setUint(bytes32 _key, uint256 _value) internal {
s.uIntStorage[_key] = _value;
}
function setUint(bytes32 _key, uint _value) onlyLatestVersion external {
uIntStorage[_key] = _value;
}

Because the Proxy pattern is already used, the Eternal Storage pattern is not necessary and just complicates the source and uses a lot of gas.

Recommendation:

Choose either the Proxy pattern or the Eternal Storage pattern.
Use the same chosen pattern for allowances (see bugs above).

Definition of Done

• Time boxed to 1 day, check to see gas savings of the following
• DAO struct lives on ElasticDAO
• elasticGovernanceTokenAddress lives on ElasticDAO
• Token struct lives on ElasticGovernanceToken
• TokenHolder struct lives on ElasticGovernanceToken
• mapping(address => TokenHolder) struct lives on ElasticGovernanceToken
• before and after gas estimations for all model related write functions