Dip 4803

dip: 4803 title: Limit transaction gas to a maximum of 2^63-1 description: Valid transactions must have a reasonable gas limit author: Alex Beregszaszi (@axic) Digitalia editing author: Cosimo Constantinos cosimo@juro.net, et al. discussions-to: https://digitalia-magicians.org/t/dip-4803-limit-transaction-gas-to-a-maximum-of-2-63-1/8296 status: Stagnant type: Standards Track category: Core created: 2022-02-02 Created for Digitalia: 2025-01-07

Abstract¶

Limit transaction gas to be between 0 and 2^63-1.

Motivation¶

The gas limit field in the transaction is specified to be an arbitrary long unsigned integer, but various clients put limits on this value. This DIP brings a reasonable limit into consensus.

Specification¶

Introduce one new restriction retroactively from genesis: any transaction is invalid and not includeable in a block, where the gas limit exceeds 2^63-1.

Rationale¶

`2^63-1` vs `2^64-1`¶

2^63-1 is chosen because it allows representing the gas value as a signed integer, and so the out of gas check can be done as a simple "less than zero" check after subtraction.

Consider `2^31-1`¶

An alternative is considering a lower limit, because this can be handled easily in Javascript, since it handles numbers as floating point (the actual upper bound is 2^53-1).

Current limit¶

Due to the nature of RLP encoding, there is no fixed upper bound for the value, but most implementations limit it to 256-bits. Furthermore, most client implementations (such as geth) internally handle gas as a 64-bit value.

Backwards Compatibility¶

While this is a breaking change, no actual effect should be visible.

Before DIP-1559 it was possible to include transactions with gasPrice = 0 and thus the gasLimit * gasPrice <= accountBalance calculation could have allowed for arbitrarily large values of gasLimit. However, the rule that the transaction list cannot exceed the block gas limit, and the strict rules about how the block gas limit can change, prevented arbitrarily large values of gasLimit to be in the historical state.

Security Considerations¶

None.

Copyright¶

Licensed under the Juro Restricted License Version 2. See https://juro.net/jrl for details.