2

This issue is simple to replicate using an Ethereum Grid (Geth) node, ganache-cli and truffle.

After starting the (light) Geth node:

1. Fork mainnet from Geth node

ganache-cli --fork http://localhost:8545

2. Start Truffle console

truffle console

3. Build the contract (web3js)

abi = fs.readFileSync('./test/abi/erc20.json', 'utf-8')

contract = new web3.eth.Contract(JSON.parse(abi), '0x6b175474e89094c44da98b954eedeac495271d0f') // Dai contract address (mainnet)

4. Call on a public getter

contract.methods.decimals().call()

Error

Error: Returned values aren't valid, did it run Out of Gas?

Is it possible that the Dai contract does not exist on the ganache-cli fork of the Geth node? How would I test for its existence?

truffle version

Truffle v5.1.15 (core: 5.1.15)
Solidity - 0.5.1 (solc-js)
Node v10.14.1
Web3.js v1.2.1

truffle-config.js

development: {
  host: "127.0.0.1", // Localhost (default: none)
  port: 8546, // ganache-cli
  network_id: "*" // Any network (default: none)
}

Dai Contract ABI

[{"inputs":[{"internalType":"uint256","name":"chainId_","type":"uint256"}],"payable":false,"stateMutability":"nonpayable","type":"constructor"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"address","name":"src","type":"address"},{"indexed":true,"internalType":"address","name":"guy","type":"address"},{"indexed":false,"internalType":"uint256","name":"wad","type":"uint256"}],"name":"Approval","type":"event"},{"anonymous":true,"inputs":[{"indexed":true,"internalType":"bytes4","name":"sig","type":"bytes4"},{"indexed":true,"internalType":"address","name":"usr","type":"address"},{"indexed":true,"internalType":"bytes32","name":"arg1","type":"bytes32"},{"indexed":true,"internalType":"bytes32","name":"arg2","type":"bytes32"},{"indexed":false,"internalType":"bytes","name":"data","type":"bytes"}],"name":"LogNote","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"address","name":"src","type":"address"},{"indexed":true,"internalType":"address","name":"dst","type":"address"},{"indexed":false,"internalType":"uint256","name":"wad","type":"uint256"}],"name":"Transfer","type":"event"},{"constant":true,"inputs":[],"name":"DOMAIN_SEPARATOR","outputs":[{"internalType":"bytes32","name":"","type":"bytes32"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"PERMIT_TYPEHASH","outputs":[{"internalType":"bytes32","name":"","type":"bytes32"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[{"internalType":"address","name":"","type":"address"},{"internalType":"address","name":"","type":"address"}],"name":"allowance","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"internalType":"address","name":"usr","type":"address"},{"internalType":"uint256","name":"wad","type":"uint256"}],"name":"approve","outputs":[{"internalType":"bool","name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[{"internalType":"address","name":"","type":"address"}],"name":"balanceOf","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"internalType":"address","name":"usr","type":"address"},{"internalType":"uint256","name":"wad","type":"uint256"}],"name":"burn","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"decimals","outputs":[{"internalType":"uint8","name":"","type":"uint8"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"internalType":"address","name":"guy","type":"address"}],"name":"deny","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"internalType":"address","name":"usr","type":"address"},{"internalType":"uint256","name":"wad","type":"uint256"}],"name":"mint","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"internalType":"address","name":"src","type":"address"},{"internalType":"address","name":"dst","type":"address"},{"internalType":"uint256","name":"wad","type":"uint256"}],"name":"move","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"name","outputs":[{"internalType":"string","name":"","type":"string"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[{"internalType":"address","name":"","type":"address"}],"name":"nonces","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"internalType":"address","name":"holder","type":"address"},{"internalType":"address","name":"spender","type":"address"},{"internalType":"uint256","name":"nonce","type":"uint256"},{"internalType":"uint256","name":"expiry","type":"uint256"},{"internalType":"bool","name":"allowed","type":"bool"},{"internalType":"uint8","name":"v","type":"uint8"},{"internalType":"bytes32","name":"r","type":"bytes32"},{"internalType":"bytes32","name":"s","type":"bytes32"}],"name":"permit","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"internalType":"address","name":"usr","type":"address"},{"internalType":"uint256","name":"wad","type":"uint256"}],"name":"pull","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"internalType":"address","name":"usr","type":"address"},{"internalType":"uint256","name":"wad","type":"uint256"}],"name":"push","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"internalType":"address","name":"guy","type":"address"}],"name":"rely","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"symbol","outputs":[{"internalType":"string","name":"","type":"string"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"totalSupply","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"internalType":"address","name":"dst","type":"address"},{"internalType":"uint256","name":"wad","type":"uint256"}],"name":"transfer","outputs":[{"internalType":"bool","name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"internalType":"address","name":"src","type":"address"},{"internalType":"address","name":"dst","type":"address"},{"internalType":"uint256","name":"wad","type":"uint256"}],"name":"transferFrom","outputs":[{"internalType":"bool","name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"version","outputs":[{"internalType":"string","name":"","type":"string"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[{"internalType":"address","name":"","type":"address"}],"name":"wards","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"}]
5
  • 1
    Sure the connection is well established? Like, does web3.eth.getBlockNumber returns expected? Mar 5, 2020 at 10:15
  • Yikes: web3.eth.getBlockNumber() // 82
    – Nick
    Mar 5, 2020 at 10:16
  • The contract at 0x6b175474e89094c44da98b954eedeac495271d0f does not implement function decimals() Mar 5, 2020 at 10:18
  • @goodvibration it's a public storage variable so it should create its own getter function right?
    – Nick
    Mar 5, 2020 at 10:19
  • Yes, but this means that your contract implements this getter, not that the contract deployed at that address does. Mar 5, 2020 at 10:25

1 Answer 1

0

With contract = new web3.eth.Contract(abi, addr),

The one and only reason for contract.methods.decimals().call() to throw:

Error: Returned values aren't valid, did it run Out of Gas?

Is if no contract which implements function decimals() is deployed at addr.

2
  • 1
    It transpired that João Quintanilha was correct in the comments, it was an issue in the Geth node not syncing to the latest block. The contract did not exist according to Geth and so this error was thrown. contract.methods.decimals().call() does now return 18 which is the value of the public storage variable decimals.
    – Nick
    Mar 5, 2020 at 10:22
  • @Nick: Yes, I have slightly updated the answer (the last line). Mar 5, 2020 at 10:24

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