forked from DecentralizedClimateFoundation/DCIPs
74 lines
3.0 KiB
Markdown
74 lines
3.0 KiB
Markdown
---
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eip: 897
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title: DelegateProxy
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author: Jorge Izquierdo <jorge@aragon.one>, Manuel Araoz <manuel@zeppelin.solutions>
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type: Standards Track
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category: ERC
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status: Stagnant
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created: 2018-02-21
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discussions-to: https://github.com/ethereum/EIPs/pull/897
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---
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## Simple Summary
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Proxy contracts are being increasingly used as both as an upgradeability mechanism
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and a way to save gas when deploying many instances of a particular contract. This
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standard proposes a set of interfaces for proxies to signal how they work and what
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their main implementation is.
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## Abstract
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Using proxies that delegate their own logic to another contract is becoming an
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increasingly popular technique for both smart contract upgradeability and creating
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cheap clone contracts.
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We don't believe there is value in standardizing any particular implementation
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of a DelegateProxy, given its simplicity, but we believe there is a lot of value
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in agreeing on an interface all proxies use that allows for a standard way to
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operate with proxies.
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## Implementations
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- **aragonOS**: [AppProxyUpgradeable](https://github.com/aragon/aragonOS/blob/master/contracts/apps/AppProxyUpgradeable.sol), [AppProxyPinned](https://github.com/aragon/aragonOS/blob/master/contracts/apps/AppProxyPinned.sol) and [KernelProxy](https://github.com/aragon/aragonOS/blob/master/contracts/kernel/KernelProxy.sol)
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- **zeppelinOS**: [Proxy](https://github.com/zeppelinos/labs/blob/2da9e859db81a61f2449d188e7193788ca721c65/upgradeability_ownership/contracts/Proxy.sol)
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## Standardized interface
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```solidity
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interface ERCProxy {
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function proxyType() public pure returns (uint256 proxyTypeId);
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function implementation() public view returns (address codeAddr);
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}
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```
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### Code address (`implementation()`)
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The returned code address is the address the proxy would delegate calls to at that
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moment in time, for that message.
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### Proxy Type (`proxyType()`)
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Checking the proxy type is the way to check whether a contract is a proxy at all.
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When a contract fails to return to this method or it returns 0, it can be assumed
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that the contract is not a proxy.
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It also allows for communicating a bit more of information about how the proxy
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operates. It is a pure function, therefore making it effectively constant as
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it cannot return a different value depending on state changes.
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- **Forwarding proxy** (`id = 1`): The proxy will always forward to the same code
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address. The following invariant should always be true: once the proxy returns
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a non-zero code address, that code address should never change.
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- **Upgradeable proxy** (`id = 2`): The proxy code address can be changed depending
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on some arbitrary logic implemented either at the proxy level or in its forwarded
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logic.
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## Benefits
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- **Source code verification**: right now when checking the code of a proxy in explorers
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like Etherscan, it just shows the code in the proxy itself but not the actual
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code of the contract. By standardizing this construct, they will be able to show
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both the actual ABI and code for the contract.
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## Copyright
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Copyright and related rights waived via [CC0](../LICENSE.md).
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