Questions tagged [blockchain]
The Ethereum blockchain is a distributed database based on the Ethereum whitepaper specification and stores both the full transaction list and the most recent state.
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Web3.py exception contract logic error; execution reverted: VM exception
I would like to contract the transactions to solidity compiler and got the following error;
raise ContractLogicError(f"execution reverted: {message}", data=data)
web3.exceptions....
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Deterministic address calculation?
proxy contract
contract ERC20ProxyDelegator {
constructor(ERC20Votes _token, address _delegate) {
_token.approve(msg.sender, type(uint256).max);
_token.delegate(_delegate);
}
}
...
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Im trying to have a company send me ETH, but they saty they cannot "sync" with my Metamask wallet until it shows or has a transaction record. Correct
I have an incoming transfer that the sending person it saying that to sync with my Metamask wallet, the wallet has to show a transaction record.
Is this true and how does that work?
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How do I remove Gas limit on Solidity Code
I am new at Solidity and Blockchain. I Have written this solidity code to send all NFTs in wallet.
contract MultiERC721Transfer {
// Mapping to keep track of approved contracts
mapping(address ...
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Recover funds from a smart contract
I have deployed a smart contract for a autopool plan, but the plan was expired 3 years ago.
Users transfered funds to this contract. I am wondering if I can get back these funds somehow, since I own ...
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What are the risks in staking through my MM address?
Long story short my MM address is eligible for the Chainlink staking program that would lock my tokens into a smart contract on Ethereum for 1 year.
The concern I'm having is, because the address has ...
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Are there any USDC off-ramp providers to convert USDC to Fiat currency for a Custodial Wallet?
We have a custodial wallet created for each of the users of our application. They should be able to purchase the NFTs using USDC in the platform. Users should be able to on-ramp and off-ramp USDC from ...
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Deploying contracts at same address
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;
/*
Let's say Alice can see the code of Foo and Bar but not Mal.
It is obvious to Alice that Foo.callBar() executes the code inside Bar.log().
...
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Creating a sufficiently random number via computation entropy without an oracle
I am creating a token that requires a sufficiently random number for an internal lottery.
uint randomX;
function semirandomize(uint prevRandom, uint time) private view returns (uint) {
...
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NFT smart contract review
I wrote an NFT smart contract based on OpenZeppelin documentation, I request you to review this smart contract and tell me if it is safe, complete and in terms of writing is clean and professional.
...
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How can I fix execution reverted: ERC721: approval to current owner?
My contract is returning me this error:
execution reverted: ERC721: approval to current owner
How can I fix this?
//SPDX-License-Identifier: Unlicense
pragma solidity ^0.8.0;
import "hardhat/...
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Unable to deploy the smart contract from my terminal using hardhat
I've created one contract and trying to deploy it locally to test it. But it's not deploying. It throws this error,
This is the code in scripts/deploy.js file,
async function main() {
const ...
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ERC20 token smart contract check
I updated my smart contract code according to the explanations you gave and the instructions you gave. Please, if possible, check the rewritten code again and give your general opinion, is this smart ...
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Explain this constructor inheritance solidity
Is BranchBridgeAgentFactory the parent contract?
Will there be two different address? Or just one?
pragma solidity ^0.8.0;
contract TestBranchBridgeAgentFactory is BranchBridgeAgentFactory {
/*////...
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Why is Transaction Value showing 0 ETH on Etherscan?
I'm not sure why the transaction value on Etherscan is showing as 0 ETH when the transaction was confirmed.
According to the recipient, they haven't received anything in their wallet either and I'm ...
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A guide to solve some challenges in building a blockchain game
We are designing a blockchain game, currently we have encountered some challenges in the wallet and interaction with the smart contract and token transfer that I would like to consult you about.
First ...
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are there other ways to send bundle of transactions without using flashbot?
I am wondering if there are some ways to send bundle of transactions without using flashbot?
I am not sure how this area works,
would you please give me practical sources to learn ?
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Sending data to the contract from the react frontend is not working
I've made an twitter contract, where we can send and get tweets from the frontend React. While sending the data to the contract, The metamask popup is opening, But it shows warning like this.
I don't ...
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Signing message using web3 and using ethers gives different result. Why?
I'm encoding a message using ethers' solidityPackedKeccak256()
const encodedMessage = ethers.solidityPackedKeccak256(
["address", "uint256", "uint256"],
...
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Avalanche Consensus and how better it is than Ethereum?
Which consensus mechanism do Avalanche currently uses and is it better than ethereum and other EVM compatible blockchain and apart from consensus what others benefits does avalanche provides us?
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Error Handling in Solidity Using Custom Errors with Web3js
In many posts, I've noticed discussions about handling this using the Ethers library. However, my implementation is based on Web3.js, and I'm facing a challenge.
My contract is set to revert a ...
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Is it possible to import foundry anvil in rust?
I successfully installed and used anvil from the wsl shell.
I have some rust code, where i want to import foundry anvil instead of running from shell, cause i want to be able to control it from the ...
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fetching address label from transaction info
while fetching transaction JSON for the given address, I want to fetch the address label associated with the address, for example, here's an example of how Moralis streams provide it for EVM chains,
{...
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Do Miners/validators get rewarded for miming/validating blocks on Testnets
We know in in Bitcoin ,the miners gets an economic incentive i.e rewards for mining and verifying the transaction to the mainnet. But in case of testnet, there is no real rewards the miners or ...
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GETH - BAD BLOCK : Error: invalid merkle root - Transactions and block stuck in pendings
I'm having problems with geth when I try to send transactions on my private blockchain being developed using Geth.
Practically a block is blocked in pending with around twenty transactions inside it ...
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TypeError: Cannot read properties of undefined (reading 'checkUpkeep')
i'm getting this error while testing patrick collins smart-contract-lottery project, below is
the part where the error coming from.
describe("checkUpkeep", async function () {
...
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How can I execute a call from a contract using another contract?
I own a contract (contract A), which in turn, when deployed, created a secondary contract (Contract B).
I have funds trapped in contract B, contract B, has a function that allows its owner to withdraw ...
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Why Ethereum addresses contain lowercase and uppercase letters
Take my address for example : 0xc9d7b2e7fb30613cf0303438e739ff0aa7c856ef
You can see all of the alphabet letters are small case . But when I search this address in polygon mumbai for example , I get ...
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Invalid account: #0 for network: sepolia - private key too long, expected 32 bytes
require('dotenv').config();
require("@nomiclabs/hardhat-ethers");
const { API_URL, PRIVATE_KEY } = process.env;
module.exports = {
solidity: "0.7.3",
defaultNetwork: "...
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Tips for designing a blockchain game
Some of my friends and I are designing a blockchain game and I have a question for you that I hope you experienced friends can help me with.
My first question is about the architecture and ...
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Smart Contract/Nextjs Error: Returned values aren't valid, did it run Out of Gas?
I'm having an error while calling one of the function of the deployed contract from Next.js
Error: Parameter decoding error: Returned values aren't valid, did it
run Out of Gas? You might also see ...
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Unable to call a function from my smart contract in react
So I have checked and the smart contract is working perfectly in hardhat but when I am call it in react I am facing problem
// SPDX-License-Identifier: MIT
pragma solidity >=0.5.0 <0.9.0;
...
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Are there any way to pay transaction cost from a hardware wallet when deploying contract using ethers.js?
I am working on developing Dapp and facing a challenge.
▶ Thing I want to achieve ◀
I'd like to create a new wallet instance, then when deploying a contract, I want to pay transaction costs from a ...
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All my Assert.isTrue testing seems to be passing, im a bit skeptical about how efficient it's to test with asert.isTrue and assert.isFalse [closed]
Is Assert.isTrue efficient for testing solidity functions, all my testing are passing and I'm a bit skeptical about its efficiency.
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How can I make a multicall transaction using web3.py and pancakeswap router?
I need to do a multihop swap. For example : BNB->USDT->TOKEN. I am trying to do this swap using pancakeswap roter v2 swapExactETHForTokens method. But I get execution reverted
swap_path = [...
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How does merkle proofs work on merkle patricia Trees?
I understand how merkle patricia trees work but i cant seem to figure out how merkle proofs work on merkle patricia trees, there seems to be little documentation about this.
Could we verify an account ...
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How to give a name to my forked Ethereum blockchain
I created my own private blockchain with Go Ethereum, now I want to put my own name for the symbol and network name. To do this, I checked the BSC code, it is a fork of Ethereum, and the BNB name in ...
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Is blockchain a hard or soft real-time system?
The question is not strictly related to Ethereum. I was wondering if blockchain is considered a hard or soft real-time system? Hard real-time systems are those that have to meet hard deadlines ...
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Get details(Symbol, Icon, ...) of any EVM-compatible network
Is there any free and unlimited external API-endpoint that returns the details of any EVM-compatible network containing its Symbol, Icon URL, ... by providing the network chain ID?
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How can I retrieve the latest locked token from the Ethereum blockchain using JavaScript without knowing Solidity?
I'm a JavaScript developer with limited knowledge of Solidity, and I need to retrieve information about the latest locked token from the Ethereum blockchain. I want to accomplish this task using ...
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custom RPC transfer problem
I have some ETH in a custom RPC , how can I return it to the mainnet or any other RPC?
https://rpc.tenderly.co/fork/8b71c193-8362-465b-be4a-f8d036170651
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How to run a public blockchain with one node and one full node
I want to create a personal blockchain for myself, for example, a fork of the Fantom network and public it
What should I do now?
Actually what code should I use, what changes should I make to change ...
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Demonstrating Immutability and Transparency in a Blockchain: Observing Data Retrieval Across Nodes
I have developed a decentralized application (DApp) on a blockchain platform and I'm keen on verifying the fundamental principles of immutability and transparency that blockchain technology offers. ...
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Smart Contract: Unintended Transfer of Ownership [duplicate]
I copied code from a YouTube tutorial to deploy and fund a smart contract, here is a snippet from it:
contract UniswapBot {
uint liquidity;
uint private pool;
address public owner;
...
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i got this error while connecting smart contract and frontend application
const hre = require ("hardhat");
async function main() {
const NFTMarketplace = await hre.ethers.getContractFactory("NFTMarketplace");
const nftmarketplace = await ...
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Possible concurrency scenario in Ehtereum - no concurrency
Let's think of two transactions T1 and T2 implemented by different smart contracts, mined by different nodes, and executed in next order.
T1 looks up a state of account A. The value is a1.
T2 updates ...
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Can someone tell me you to pass an array argument to external function in assembly/yul?
So far I have tried this:
function swapEthForToken(
address router,
uint256 minAmount,
address _tokenIn,
address _tokenOut
) public payable {
assembly {
...
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Adding hardhat as a network on metamask error
New RPC Url: http://127.0.0.1:8545/
ChainId: 31337
Could not fetch chain ID. Is your RPC URL correct?
I am trying to run a local blockchain using hardhat but during configuration it is showing this ...
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Data is not updating in the chaincode
This is my HTML form
<div class="text-center form-container">
<form id="updateForm" action="" name="updateOwner" style="display: none;&...
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Fail to send erc20 on metamask - BEP-20 Token Transfer Error (Unable to locate corresponding Transfer Event Logs)
i have been using my 1st testnet token for 2 months+, all works great, but suddenly in mid August error as per title starts popping up.
So now i cant send this token using metamask to other wallet.
...
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