1.9 KiB
Preamble
EIP: <to be assigned>
Title: REVERT instruction in the Ethereum Virtual Machine
Author: Alex Beregszaszi, Nikolai Mushegian (nikolai@nexusdev.us)
Type: Standard Track
Category: Core
Status: Draft
Created: 2017-02-06
Simple Summary
The REVERT instruction provides a way to stop execution and revert state changes, without consuming all provided gas and with the ability to return a reason.
Abstract
The REVERT instruction will stop execution, roll back all state changes done so far and provide a pointer to a memory section, which can be interpreted as an error code or message. While doing so, it will not consume all the remaining gas.
Motivation
Currently this is not possible. There are two practical ways to revert a transaction from within a contract: running out of gas or executing an invalid instruction. Both of these options will consume all remaining gas. Additionally, reverting a transaction means that all changes, including LOGs, are lost and there is no way to convey a reason for aborting a transaction.
Specification
The REVERT instruction is introduced at 0xfd. Execution is aborted and state changes are rolled back.
It expects two stack items, the top item is the memory_length followed by memory_offset. Both of these can equal to zero. The cost of the REVERT instruction equals to that of the RETURN instruction.
In case there is not enough gas left to cover the cost of REVERT or there is a stack underflow, the effect of the REVERT instruction will equal to that of a regular out of gas exception.
The content of the optionally provided memory section is not defined by this EIP, but is a candidate for another Informational EIP.
Rationale
TBD
Backwards Compatibility
This change has no effect on contracts created in the past.
Test Cases
TBA
Copyright
Copyright and related rights waived via CC0.