59 lines
1.6 KiB
Markdown
59 lines
1.6 KiB
Markdown
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---
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eip: 2488
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title: Deprecate the CALLCODE opcode
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author: Alex Beregszaszi (@axic)
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discussions-to: https://ethereum-magicians.org/t/eip-2488-deprecate-the-callcode-opcode/3957
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status: Stagnant
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type: Standards Track
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category: Core
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created: 2019-12-20
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requires: 7
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---
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## Abstract
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Deprecate `CALLCODE` in a *somewhat* backwards compatible way, by making it always return failure.
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## Motivation
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`CALLCODE` was part of the Frontier release of Ethereum. In the first few weeks/months it became clear
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that it cannot accomplish its intended design goal. This was rectified with introducing `DELEGATECALL`
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([EIP-7](./eip-7.md)) in the Homestead update (early 2016).
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`CALLCODE` became never utilized, but it still puts a burden on EVM implementations.
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Disabling it will not improve the situation for any client whose goal is to sync from genesis, but would
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help light clients or clients planning to sync from a later point in time.
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## Specification
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If `block.number >= FORK_BLOCK`, the `CALLCODE` (`0xf2`) instruction always returns `0`, which signals failure.
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## Rationale
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It would be possible just to remove the opcode and exceptionally abort if it is encountered.
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However, by returning failure, the contract has a chance to act on it and potentially recover.
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## Backwards Compatibility
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This is a breaking change and has a potential to break contracts. The author expects no contracts of any value
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should be affected.
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TODO: validate this claim.
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## Security Considerations
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TBA
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## Test Cases
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TBA
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## Implementation
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TBA
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## Copyright
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Copyright and related rights waived via [CC0](../LICENSE.md).
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