Questions tagged [contract-development]

Questions regarding the development of smart contracts

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Not able to fetch correct APY in aave mumbai

I am following this doc - APY and APR - Developers to fetch lending and borrowing rates in mumbai for usdc but they doesn’t seem to be correct and are different from aave staging UI, how can I solve ...
Varun Sharma's user avatar
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1 answer
9 views

Calling Uniswap Multihop Function returns Error

Deployed on Polygon Mumbai. Code compiles fine on REMIX and is meant to perform multihop swaps on Polygon Mumbai, but it returns error after function is called. Deployed Contract always funded with ...
Samuel Aniss's user avatar
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1 answer
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What will happened to my WETH TOKEN if the receiver or the network didn't support WETH TOKEN

I send WRAPPED ETH to a wallet/network which is COINS PH WALLET that has supported ETH ADDRESS, i thought WETH and ETH are the same? Now my problem is how can i possible retrieve my TOKEN?
Omar's user avatar
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The function runs external, but not internal

mapping(string => mapping(uint256 => Order[])) buyOrders; mapping(string => mapping(uint256 => Order[])) sellOrders; function placeBuyOrder(string memory stockName, uint256 price, uint32 ...
Eilys's user avatar
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Methods not appearing when printing contract but do appear on Etherscan

I have a goerli testnet contract you can check out here. I'm trying to call executeFlashLoan using a javascript function using web3js, but the code acts as if the function doesn't exist. However, it'...
Trent Kennelly's user avatar
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1 answer
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How can I get a defi site source code?

I'm trying to expose a defi scam website which copycats a famous platform on TRX blockchain. I have their transaction address, but no source code or website's contract address. I was wondering if ...
Sina Blank's user avatar
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Anti Sniper / anti Snipe Bot for newly listed token on pancakeswap

Can Somebody explain how to have Bot Protection enabled against sniper bot for a token contract which is going to launch on pancakeswap or on any other decentralised exchange. do we have to create ...
Bhushan Dhiware's user avatar
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Need help writing up a smart contract [closed]

As part of a larger project, I need help implementing Shamir's Secret Sharing algorithm in Ethereum and IPFS. I am an UG engineering student and have just got out of a month long stay in the ICU due ...
Ahleya's user avatar
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Is nonce necessary to prevent signature replay on smart contracts if the method is idempotent?

I have a smart contract in which only I can submit transactions through onlyOwner modifier. If users want to interact with the contract, I make the users sign the parameters of the method and verify ...
Ahmet Yazıcı's user avatar
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1 answer
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How to build a 3 contract structure with delegatecall

I'm looking for help to build an intermediate contract using delegatecall. My challenge would be with 3 contracts. I need contract A to be the owner of Contract B, and contract B to have a ...
Leandro Loures's user avatar
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How can this contract buy and sell a token multiple times in one transaction?

I have discovered a contract that can buy and sell multiple times within the same transaction. How does that contract work, and where can I find this contract? Thank you. https://etherscan.io/tx/...
The Fat Cat's user avatar
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The WETH / 4 2.0 pair already has liqudity on Uniswap V2. You cannot create a presale for this pair as the price is already set

The WETH / 4 2.0 pair already has liqudity on Uniswap V2. You cannot create a presale for this pair as the price is already set. So how do I get my tax token to market, And if my token or contract ...
4 Cure's user avatar
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1 answer
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provider.broadcastTransaction is not a function

I'm trying to call a contract function on the avalanche network. However I'm running into this error. Interestingly, the transaction goes through on hardhat network however fails on a evm testnest (...
Ibra's user avatar
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How to find the data sent to create a new Smart Contract

I am currently learning Solidity & Blockchain development. Came across an instance, where a new ERC20 Token contract was created from a front end App. While checking the Contract, I found a bunch ...
BlockChain Learner's user avatar
1 vote
1 answer
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How to call smart contracts in Web3j

I wrote this code in TS using web3 library: // ABI = my deployed SmartContract as json ABI const daiToken = new web3.eth.Contract(Abi as AbiItem[], smartContractAdress) const smartContractFunction = ...
Paweł Krupski's user avatar
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new release of ERC1155SupplyUpgradeale has compilation issues

The new contracts lib from OZ, specifically ERC1155UspplyUpgradeable has compilation issues before even inheriting it in any child contract (check screenshot below) any idea why? or how to fix it? ...
sasha's user avatar
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Is there any way to get historical pool data by interacting with the pool smart contract?

I am wondering if there is a function in smart contract pools to get historical data (just last 100 bars for example). thanks guys!
Aniss Itaoui's user avatar
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Requirement for running node on etherum

i'm planning to run a node to do some works for learning such as snipping token, decode transaction from mempool in real-time which low latency? I just wonder which configuration that i need to do ...
dang.pm.IT's user avatar
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4 answers
54 views

Gas estimation errored with the following message (see below). The transaction execution will likely fail. Do you want to force sending

Gas estimation errored with the following message (see below). The transaction execution will likely fail. Do you want to force sending? Returned error: {"jsonrpc":"2.0","...
Ramy Selim's user avatar
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2 answers
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Call a function from another contract, entirely determined by initial contract's function arguments

I would like to have a contract MainContract that can call any other contract functions depending on arguments given a MainContract function. It would look like this: pragma solidity 0.8.16; contract ...
Pacdac's user avatar
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How to fix `Invalid callback object specfied` error when deploying a smart contract?

My smart contract: // SPDX-License-Identifier: MIT pragma solidity 0.8.19; contract Inbox { string public message; constructor (string memory initiialMessage) { message = ...
Jyobala's user avatar
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NFT transfer to a contract in ERC1155 standard

NFTS transfer from minter to contract isn't working, below is the detailed problem. NFT.sol // SPDX-License-Identifier: UNLICENSED pragma solidity ^0.8.19; import {ERC1155} from "@openzeppelin/...
Shubham's user avatar
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1 vote
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Issue creating pair on IUniswapV2Factory (sepolia)

I have the following interfaces in my contract file: interface IUniswapV2Factory { function createPair(address tokenA, address tokenB) external returns (address pair); } interface ...
Timmy12321's user avatar
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2 answers
41 views

Transaction gets reverted when using send web3 function

I have a basic smart contract that sets the hash of a string and retrieves it along with verification. The contract works perfectly fine, but the issue is with the .send method of web3 that reverts ...
Andrea Ross's user avatar
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1 answer
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how to chech the address that buys the highest amount on a contract

What is the process for identifying the address that has made the largest purchase amount within a specific contract?"
trodd Highzik's user avatar
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0 answers
14 views

Asking too much gas fee for transaction, Returned error: theta RPC returns an error

I have deployed my contract on theta mainnet. It was working fine for few days but now it is asking too much gas fee for transaction. I am using web3 "v1.3.1" on server side nodejs
Ilyas Khan's user avatar
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Is it possible to pay gas fee for transaction from contract? [duplicate]

I have created function for consumer to deposited balance into contract, My goal is to deduct gas fee for purchasing subscription from his/her deposited balance as same as subscription is deducting ...
Ilyas Khan's user avatar
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1 answer
41 views

I want to pay gas fee from contract, Is it possible? [duplicate]

// here is my contract // SPDX-License-Identifier: MIT pragma solidity ^0.8.0; library SafeMath { function add(uint256 a, uint256 b) internal pure returns (uint256) { uint256 c = a + b; ...
Ilyas Khan's user avatar
0 votes
1 answer
129 views

error: "Transaction has been reverted by EVM"

I'm fairly new to Solidity and coding overall. I'm going through a Udemy course and I ran into an error which I can't find the solution for. I deployed a contract on the Sepolia test network from ...
Arad11222's user avatar
2 votes
1 answer
194 views

Failed to parse as type `uint256`: a character is not in the range 0-9

I am following Patrick Collins Smart Contract Lottery development and trying to run the deploy script test net ( sepolia ) but I am getting this error Error: Failed to parse as type `uint256`: a ...
Iftikhar uddin's user avatar
1 vote
1 answer
32 views

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. ...
Ali's user avatar
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3 votes
2 answers
51 views

Are storage variables tightly packed like struct fields?

Tight variable packing is a known coding pattern in Solidity for saving gas by placing struct fields that are lower than 256 bits closer to one another. Does this logic apply to storage variables? ...
Paul Razvan Berg's user avatar
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2 answers
37 views

How to call public view functions from Contract in a local hardhat node forking a public network?

I have a Hardhat project with a sample storage contract. There are 2 functions: Public view function Public write function (creates a transaction) My Hardhat project forks an Ethereum mainnet public ...
Alexander Herranz's user avatar
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2 answers
29 views

How do you calculate the number of tokens that are worth 1 eth before swapping in Uniswap pool?

I want to make a function for my token contract that allows me to swap a dynamic amount of tokens in exchange for 1 eth. Is it possible to calculate how many tokens are worth 1 eth and then swap with ...
Pen Tester's user avatar
1 vote
0 answers
27 views

How is the derivation of the Constant Product AMM formula of Uniswap?

I was researching about Uniswap v1 and I found that the code is using the following formula to get the amount out of a swap: Formula: Reference to code Everyone says that this formula is derived of ...
santipu_'s user avatar
1 vote
2 answers
170 views

Remove the element from array where order matters?

I am presenting my use case here. Let's think of a dating app where each candidate enters their preferences and we store their data and add them to an array. when someone enters that matches with any ...
Rashid Ul Haq's user avatar
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1 answer
26 views

How do you use the Diamond Pattern for escrow upgrades?

I am creating a contract with the diamond pattern so I can evolve and add new features to my contract. Contract facets: Contract A: an ERC721 that takes care of minting its own NFTs Contract B: ...
Piyush Chittara's user avatar
1 vote
0 answers
16 views

Is there any way to read block attestation from inside a solidity smart contract?

Are there any precompiles, or any other native ways to get block attestation data from ETH2 POS inside a solidity contract?
Bruce's user avatar
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1 vote
1 answer
104 views

Where to place special functions receive() & fallback()?

receive() external payable { fund(); } fallback() external payable { fund(); I want to find out where exactly should these special functions be wrriten; should they come before the contract ...
progress Ibrahim's user avatar
0 votes
1 answer
39 views

Can I edit in the msg.sender value for the called contract?

let's assume following solidity contracts: contract EntryPointContract { address one = '0x...'; address two = '0x...'; address delegateContract; constructor(address ...
Jaroslaw Piatek's user avatar
1 vote
1 answer
22 views

How to call a function from a separate contract

I have a already deployed contract and it has a withdraw() function. And i want to create another contract that first send some ETH to the target contract and then call the withdraw() to withdraw ...
Arkonomi's user avatar
0 votes
1 answer
55 views

Is there any way to mint an NFT with metadata without passing URI in mint?

I want to create an application that receives a contract address and create a frontend for other users to mint the NFTs from that contract. But I don't have any metadata for that contract, could this ...
Vitor M. Almeida's user avatar
1 vote
1 answer
93 views

Optimizing Gas Costs in Solidity Smart Contracts: Best Practices?

I'm working on a Solidity smart contract and I'm concerned about the gas costs associated with its execution. I want to optimize my contract for gas efficiency to save on transaction fees and improve ...
Mehran Ra's user avatar
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2 votes
1 answer
103 views

Error encountered during contract execution [execution reverted]

I am trying to execute the method "withdrawICOFunds" but I am getting an error in Mainnet. In Goerli works ok Any idea what's wrong? Transaction failed: https://etherscan.io/tx/...
Esteban restrepo's user avatar
0 votes
1 answer
37 views

Auto generating a solidity based smart contracts

I have recently built a Custom UI and integrated it into a jupyterlab notebook environment. This UI helps the data owners define the sharing policies on the basis of the carefully chosen constraints, ...
Lord's Lord's user avatar
1 vote
1 answer
36 views

Is using a mapping as argument scalable?

Is a function with an argument that is a mapping scalable in terms of gas? If too many elements are added in this mapping, would it become problematic for the protocol? Example: mapping(uint256 ...
IBeFrogs's user avatar
0 votes
2 answers
187 views

Error: gas required exceeds allowance or always failing transaction in Remix

Im trying to deploy my NFT contract and works fine but only if i mint less then 1000 nfts. When i tried to raise up to 2000, 5000, 8000 and even 10000 i got the gas exceeds allowance error. Can some ...
kauan's user avatar
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1 vote
1 answer
45 views

where does the problem of this transaction come from?

So i've been working on a smart contract and im trying to perform a swap on uniswap using polygon mainnet but im struggling to get it to work, This is the solidity code im using: // SPDX-License-...
Paucar's user avatar
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1 vote
1 answer
47 views

mint NFT for contract address. it is possible to mint nft by passing contract address?

we have 2 contracts which is deployed on Bsc network. the first contract is NFT Contract and the second one is Gataway contract were we accept payment and currency swaps Please find below code Nft ...
Harish Manthurthi's user avatar
1 vote
1 answer
42 views

How to calculate make precision calculations with very small ETH amounts?

In the given scenario that I have the following code, in which a user sets a token amount and an ETH amount, I want to determine a price of token using the following code: pricePerToken = (ethAmount * ...
Samuel Sandoval's user avatar

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