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metamask-extension/app/scripts/controllers/transactions/tx-gas-utils.js
Mark Stacey 5b5b67a985
Fix default gas race condition (#8490)
A race condition exists where after adding an unapproved transaction,
it could be mutated and then replaced when the default gas parameters
are set. This happens because the transaction is added to state and
broadcast before the default gas parameters are set, because
calculating the default gas parameters to use takes some time.
Once they've been calculated, the false assumption was made that the
transaction hadn't changed.

The method responsible for setting the default gas now retrieves an
up-to-date copy of `txMeta`, and conditionally sets the defaults only
if they haven't yet been set.

This race condition was introduced in #2962, though that PR also added
a loading screen that avoided this issue by preventing the user from
interacting with the transaction until after the gas had been
estimated. Unfortunately this loading screen was not carried forward to
the new UI.
2020-05-01 12:25:45 -03:00

90 lines
2.9 KiB
JavaScript

import EthQuery from 'ethjs-query'
import { hexToBn, BnMultiplyByFraction, bnToHex } from '../../lib/util'
import log from 'loglevel'
/**
* Result of gas analysis, including either a gas estimate for a successful analysis, or
* debug information for a failed analysis.
* @typedef {Object} GasAnalysisResult
* @property {string} blockGasLimit - The gas limit of the block used for the analysis
* @property {string} estimatedGasHex - The estimated gas, in hexidecimal
* @property {Object} simulationFails - Debug information about why an analysis failed
*/
/**
tx-gas-utils are gas utility methods for Transaction manager
its passed ethquery
and used to do things like calculate gas of a tx.
@param {Object} provider - A network provider.
*/
export default class TxGasUtil {
constructor (provider) {
this.query = new EthQuery(provider)
}
/**
@param {Object} txMeta - the txMeta object
@returns {GasAnalysisResult} The result of the gas analysis
*/
async analyzeGasUsage (txMeta) {
const block = await this.query.getBlockByNumber('latest', false)
// fallback to block gasLimit
const blockGasLimitBN = hexToBn(block.gasLimit)
const saferGasLimitBN = BnMultiplyByFraction(blockGasLimitBN, 19, 20)
let estimatedGasHex = bnToHex(saferGasLimitBN)
let simulationFails
try {
estimatedGasHex = await this.estimateTxGas(txMeta, block.gasLimit)
} catch (error) {
log.warn(error)
simulationFails = {
reason: error.message,
errorKey: error.errorKey,
debug: { blockNumber: block.number, blockGasLimit: block.gasLimit },
}
}
return { blockGasLimit: block.gasLimit, estimatedGasHex, simulationFails }
}
/**
Estimates the tx's gas usage
@param {Object} txMeta - the txMeta object
@returns {string} - the estimated gas limit as a hex string
*/
async estimateTxGas (txMeta) {
const txParams = txMeta.txParams
// estimate tx gas requirements
return await this.query.estimateGas(txParams)
}
/**
Adds a gas buffer with out exceeding the block gas limit
@param {string} initialGasLimitHex - the initial gas limit to add the buffer too
@param {string} blockGasLimitHex - the block gas limit
@returns {string} - the buffered gas limit as a hex string
*/
addGasBuffer (initialGasLimitHex, blockGasLimitHex) {
const initialGasLimitBn = hexToBn(initialGasLimitHex)
const blockGasLimitBn = hexToBn(blockGasLimitHex)
const upperGasLimitBn = blockGasLimitBn.muln(0.9)
const bufferedGasLimitBn = initialGasLimitBn.muln(1.5)
// if initialGasLimit is above blockGasLimit, dont modify it
if (initialGasLimitBn.gt(upperGasLimitBn)) {
return bnToHex(initialGasLimitBn)
}
// if bufferedGasLimit is below blockGasLimit, use bufferedGasLimit
if (bufferedGasLimitBn.lt(upperGasLimitBn)) {
return bnToHex(bufferedGasLimitBn)
}
// otherwise use blockGasLimit
return bnToHex(upperGasLimitBn)
}
}