Questions tagged [solidity]
Solidity is a contract-oriented, high-level language whose syntax is similar to that of JavaScript and it is designed for writing smart contracts in Ethereum to run on the EVM. Solidity is statically typed, supports inheritance, libraries and complex user-defined types among other features.
17,421
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How to pass blockNumber to viem call?
I'm trying to view the owner of a certain NFT at a specific blockNumber, when I make the viem call without the blockNumber parameter it works perfectly, however, once I try to pass a blockNumber with ...
- 1,443
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I want to call a contract method using my safe wallet address
I made a safe wallet in my panel safe wallet which is 2/3 signers. I want to use it in my access control for an admin role and use it for calling a transfer method with it only. The problem is when I ...
- 15
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Object has no member 'call' when reading smart contract in geth console
I'm following the Storage contract example from the Geth site (https://geth.ethereum.org/docs/interacting-with-geth/javascript-console-contracts)
I am unable to call a 'retrieve' function on the ...
- 101
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25
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How to exchange one nft for another from a different contract?
I have 2 ERC1155 contracts, and am looking to transfer nft2 into nft1's wallet upon checking wallet holds nft1, but not sure what I'm doing wrong.
This is my nft1 contract:
import "./NFT2.sol&...
- 1
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1
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24
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Ethers is not decoding the indexed parameters
I want to get the value from the first indexed parameter of the TokensTransferred event from the transaction logs which can look like this. You can see that the TokensTransferred event has the first ...
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1
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12
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importing other contract in remix gone wrong despite write file name or path [closed]
import "./filename.sol"
output
Error: not found SimpleStorage.sol
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0
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21
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Malicious ERC20 blocking batch withdrawals of tokens (e.g. ERC777)
I was wondering whether the following attack vector is possible in practice.
There's a batch transfer function that is intended to batch transfer the tokens owned by the contract. That function ...
- 264
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1
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39
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Error (9322): No matching declaration found after argument-dependent lookup
Here is the file which i try to run test through foundry.
//Imports
import "forge-std/Test.sol";
import {Portal} from "../src/Portal.sol";
import {IERC20} from "@openzeppelin/...
1
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1
answer
78
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Byte32 Array is not emitted as array from events
I have created this demo contract. It has a function called convertText which converts a string text into bytes32 and stores it into bytes32[] public storedData.
You can see when you call convertText()...
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1
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36
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reading and writing to a packed nested struct using inline assembly
I've been racking my brain with this for some time, and have been unable to increment and decrement specific fields inside nested structs as per the example below.
// SPDX-License-Identifier: ...
- 1
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15
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Question about foundry testing
I'm trying to create an on chain nft with Foundry. I'm basing my project on the Cyfrin course repo. Here https://github.com/Cyfrin/foundry-nft-f23.
Except that I'm not doing the Moodnft. I decided to ...
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19
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Do dynamic arrays in memory require a pointer to where the length and elements are stored in the memory?
At 29:07 of the video here:
Devcon
it is mentioned and written in the slide that dynamic arrays have pointer slot, length slot and elements after the length slot
However, when I debug the following on ...
- 127
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How to update a bug-fix UUPS implementation through a DAO vote without revealing the bug(s) it fixes?
Let's say we have a ContractProxy and ContractV1 its implementation, using the UUPS pattern. Along that, there is a DAO that has the rights to perform an update on the implementation contract. Only ...
- 70
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Is there a way to stop wallet homomorph attacks without ditching the create2 opcode?
Losses from create2 wallets that look similar to recently active wallets has surpassed $60m:
https://gbhackers.com/create2-bypass-wallet-security-alerts/
Even today I made a transaction, and noticed ...
- 141
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Why the mentioned assembly block is skipped?
A very simple function:
function test(uint256 i) public {
uint256 j;
uint256 k = 4;
assembly {
pop(4)
}
uint256 l = 5;
}
I checked debugging it in Remix but the assembly block ...
- 127
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1
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50
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What does the tilde symbol mean in Solidity integer type casting in the example below?
function _approveTokenIfNeeded(address token, address spender) private {
if (IERC20(token).allowance(address(this), spender) == 0) {
IERC20(token).safeApprove(spender, uint256(~0));...
- 264
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23
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Signature verification using ecsign and ecrecover
I am using web3.js library to sign a transaction and then verify it from the smart contract. The Signature generated on FrontEnd and as well as from the smart contract are not same..
This is the ...
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0
answers
11
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Multiple Solidity Versions in flattened file
I have deployed a contract to Mumbai Polygon testnet. While verifying and publishing source code, the flattened file has multiple solidity versions. I got the error below.
The OpenZeppelin contracts ...
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1
answer
31
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Signature verification using web3js
I am using web3 library to sign a transaction and then verify it from the smart contract. The signature is not verifying.
This is the frontend code
const DomainSeparator = ethers.keccak256(
...
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1
answer
27
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Unknown key "viaIR"
Unknown key "viaIR"
Error HH600: Compilation failed
I'm encountering the above error when I try to compile.
Here is my hardhat.config.ts
import { HardhatUserConfig } from "hardhat/...
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1
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Can require() be used to revert low level call() that were made before it?
CODE:
(success, ) = contract.call(); // low level call
if (success) {
// do something
}
// instead of below check, can I just use require(condition)?
if (!condition) {
revert();
}
Instead of ...
- 233
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0
answers
26
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Getting error when I trying to test my contract
I started coding project and I got error when trying to test him.
When I trying to call some contract function from js tester i got error:
Error: call revert exception [ See: https://links.ethers.org/...
- 13
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22
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Can't call open trading function
So I try to call the open trading function in my code which is as follows:
function openTrading() external onlyOwner() {
require(!tradingOpen,"Trading is open");
...
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1
answer
41
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How to Specify an Acceptable Range or Ignore a Field When Testing Event Emissions in Foundry?
In a foundry project I encountered a scenario where I need to test the emission of an event with specific conditions. My requirement is either to check if a field in the emitted event falls within a ...
- 1,443
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1
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16
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How signature verification works?
I have read that to sign a message we need the private key but in the below code snippet hasing is done in the 'getMessageHash' function and 'signing' is done in the 'getEthSignedMessageHash' function....
- 41
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1
answer
12
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Which contract should execute the approveAndTransferFrom function under one transaction?
I'm trying to perform approve and transfer under one tx but I don't understand which contract should be calling the approveAndTransferFrom function? Say contract A is trying to transfer tokens to ...
- 83
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1
answer
16
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Which function to use for swapping eth against token on uniswap?
I use the following code to create the swap_transaction:
swap_transaction = router_contract.functions.swapETHForExactTokens(
0, [weth_address ,token_address], account_address, int(time.time())...
- 1
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votes
1
answer
16
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require message is not coming?
Im calling storage contract from logic contract, but when i change the owner to new logic contract,
Line 27 : require(owner==msg.sender,"only owner can call");
This is not properly ...
- 244
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1
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47
views
Find slot of private variable
How do I find the slot of a private variable?
I know that Foundry has the method stdstorage.sig(), but that only works for variables with public getters, so private ones are out of scope.
Thanks!
- 713
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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/...
1
vote
1
answer
137
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Grab first 20 bytes of 32-bytes input
In solidity casting or assembly, how do I grab the first 20 bytes of this 32-bytes input: 0x00010000c900c90062fceaad00000000000000000002af416812f9bb6f2fdff5?
Thanks!
- 713
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1
answer
40
views
Is there a shortcut for "greater than or equals to" in Solidity assembly?
I have some code where I was experimenting with the Math library, namely the logarithm functions, and I figured these would be the perfect functions to optimize with assembly, after slightly improving ...
- 79
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1
answer
34
views
quoteExactInputSingle is returning error
I'm working on solidity code that uses pancakeswapV3 quoter contract to call quoteExactInputSingle. Here is the code snippet
function AnalyseTnx(address tokenPath0,address tokenPath1,uint256 amtIn)...
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1
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58
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Extracting input data when writing Forge tests/POCs
I would like to write a test in Foundry but I need to be able to first read data from a previous transaction that was submitted in some point in the past.
For example, the transaction I'm interested ...
- 47
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2
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37
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Gas estimation errored with the following message (see below). The transaction execution will likely fail. Returned error: invalid opcode
Unable to deploy this code on any chain. I have done all i could, cleared my browser and restarted my pc and still could not deploy. what could be the issue please.
// SPDX-License-Identifier: MIT
...
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2
answers
47
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ApproveUSDT function not working internally, how do I fix this?
I’m experimenting with a presale contract based on the BSC testnet, and in the contract I’m attempting to achieve the purchase of my token with USDT.
Using my own code within the contract itself, I ...
- 1
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0
answers
21
views
I deployed the launchpad contract, but the result is 0x00000. What could be the cause?
Deployer
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "./launchpad.sol";
contract Deployer is Ownable {
uint256 public launchpadCount;
uint256 public deployCost = ...
2
votes
1
answer
65
views
Call external contract with arguments in Huff
I am trying to make an external function call, with arguments, to a contract written in Solidity from a contract written in Huff. I am able to successfully call an external contract when the function ...
- 51
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votes
3
answers
35
views
How to encode param of type address
I have this function in my contract:
function removeRes(address _res) public onlyOwner {
.
.
.
}
I'm encoding ABI like:
const contractAddress = "...
- 145
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votes
1
answer
62
views
How to fix `Expected 0 arguments, but got 1` error on web3.eth.contract method?
I'm trying to make a simple function call to a view function that takes a single uint256 as input, however when I try to pass the variable, next type check gives me this error: Expected 0 arguments, ...
- 1,443
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Is it possible Randomly generate and privately store data using Chainlink?
I'm working on a social coordination game for the Chainlink Constellation Hackathon. Game mechanics are similar to Mafia, Bang! or AmongUs where roles are assigned at the onset of the game. Roles ...
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vote
1
answer
30
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Are block.timestamp and block.number still problematic under Proof of Stake?
As stated in the SWC116 (https://swcregistry.io/docs/SWC-116/) using block.timestamp and block.number in Smart Contracts under Proof of Work was problematic.
Block.timestamp could be influenced by ...
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54
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Unable to deploy on Eth mainnet
i done all the steps and when im connecting to "Injected provider" its still asking to be on EVM version: shanghai. i want to deploy the CA on the mainnet.
2
votes
2
answers
44
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Solidity automatically generated getter function returning tuple instead of struct
// SPDX-License-Identifier: MIT
pragma solidity =0.8.22;
contract A {
struct User {
string name;
uint age;
}
mapping(uint => User) public users;
function getUser(...
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2
votes
1
answer
264
views
What is a returnbomb attack?
I've read that when making an external call to an unknown contract, if the contract returns a large amount of random or junk byte it will cause some type of bug. But I dont know exact what it is and ...
- 41
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0
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10
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Who is the msg.sender in the context when calling the "super.{....}" contract method on the inherited parent contract?
The child contract's method is: (1)
function redeem(
uint256 shares,
address receiver,
address owner
) public override andSync returns (uint256 assets) {
return ...
- 264
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2
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26
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Solidity - Trouble Installing Foundry: SSL Connection Timeout"
I'm encountering an issue while trying to install Foundry using the command curl -L https://foundry.paradigm.xyz | bash. The process times out with the error message:
% Total % Received % Xferd ...
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1
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How to interact with contract methods with more complicated data structures with Nethereum?
I'm trying to interact with the smart contract that I have created.
At the moment I deploy the contract on GANACHE.
Adding new items into contract works.
This is the part that doesn't work, and it ...
- 13
1
vote
1
answer
87
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Huff language gas optimization
I am testing out using Huff language for smart contract development. It is my understanding that the benefit of Huff language is the improved gas efficiency. However, in my small test, the contract ...
- 51
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vote
1
answer
5
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Can anyone help me to solve this error (TypeError: contractInstance.isComplete is not a function)?
My Solidity code:
// SPDX-License-Identifier: MIT
pragma solidity^0.8.17;
contract Lottery {
address public manager;
address payable[] public players;
address payable winner;
bool ...
