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.
5,296
questions with no upvoted or accepted answers
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How to handle contracts in libraries when forking Uniswap?
I am creating a DEX by forking Uniswap.
If I fork Uniswap V3 then do I need to re-deploy all contracts in libraries folder?
Q 2: How Uniswap calculates the price of a token? Does it get it from ...
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2
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0
answers
142
views
Is there an alternative to Chainlink to get a random number in a solidity contract?
I'm trying to create an NFT that selects at random between 3 json metadata files. The only way I know of to do this is to use Chainlink. I've seen one tutorial that implements "@chainlink/...
- 361
2
votes
1
answer
50
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Can not interact with the deployed contract
getting this error
Error: Transaction reverted: function returned an unexpected amount of data
at Proxy.getDecimals (contracts/proxy.sol:100)
at processTicksAndRejections (node:internal/process/...
- 21
2
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BAL#401 - SENDER_NOT_ALLOWED - Not able to Join a Balancer Pool via smart contract interfacing?
I'm looking to join a pool through a smart contract. The contract interfaces with the Balancer Vault and joins the pool, the sender would be the user and the receiver of the BPT would be the contract ...
- 21
2
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40
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Hash metamask message
I have the following metamask message (type v4):
const message = {
domain: domain,
// Defining the message signing data content.
message: {
Commit: {
...
- 213
2
votes
1
answer
141
views
Is this correct way to initialize contract instance with react?
I set my contract set-up in event-handler, i did not set it in useEffect because we use useEfect when we want to stay syncronized with state update, but here we don't need to be syncronized because we ...
- 665
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55
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Truffle hit a require or revert statement in simple ERC777 constructor
I have incredibly simple code, taking straight from openzeppelin's ERC777 contract. When I run truffle migrate, however, I receive
Replacing 'Implementation'
--------------------------
*** ...
- 282
2
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173
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Seaport order fulfillment is not verifying signature
@seaport devs
I need your help.
I have been stuck in an issue. I have been using Opensea Seaport contracts for my NFT marketplace order settlement. All stuff is done except signature verification.
I ...
- 31
2
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answers
130
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Best practices for Hardhat deployment script?
As a newcomer in Solidity, I am trying to understand and create a deploy script that I will use for deploying my contracts.
Stack: Ether.js + hardhat + javascript
Here is the code that I came up with:
...
- 27
2
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58
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I have a for loop. it doesnt work on hardhat but works on mumbai testnet
I have basic chainlink vrf contract.Trying to get 12 random numbers.I want to save those random numbers in another array.
I define an array called output. in fulfillRandomWords function, simple assign ...
- 81
2
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88
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Use Brownie to send ERC20 tokens to a payable function with the amount of tokens as an argument to the function
I have the following AlgoToken contract:
interface StableCoin {
function balanceOf(address account) external view returns (uint256);
function allowance(address owner, address spender) external ...
2
votes
1
answer
307
views
How to access address mapping to array struct in hardhat solidity?
I'm writing Unit Test using hardhat for a solidity contract. There is a public mapping variable which has a mapping of address to array of struct.
struct ticket {
uint16 looteryID;
...
2
votes
1
answer
56
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unable to verify etherscan contract may be due to high optimize runs
I have used high optimize runs as 999999999 while deploying contract..
I need to verify contract on etherscan but it has range from 0-1000000 ..
what should i do?
2
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1
answer
27
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An event with unclear purpose and data emitted in transactions
I've observed this in multiple txs I've looked at, so, here's a random one on Polygon Mumbai: link.
It contains several emitted events, the last of which is this:
What is this event and how to ...
- 279
2
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356
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Between writing fuzzing tests with echidna vs writing fuzzing tests with foundry, are there any advantages one has over the other?
Deciding which tool to use to write some fuzzing tests, was curious if one tool or the other performs better at fuzz testing than the other. It seems to me that foundry will be easier to setup my ...
- 927
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60
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Strategy for choosing the number of optimizer runs for factory contracts
The number of optimizer runs in Solidity should normally be set to the expected number of times the contract will be called in its lifetime. To quote the Solidity docs:
The number of runs (--...
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2
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64
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Is there any way to bubble up custom errors without using low-level assembly?
Is there any way to bubble up custom errors without using low-level assembly?
Say you have a custom error defined like this:
contract For {
error Unauthorized();
function reverWithError() ...
- 17.3k
2
votes
1
answer
16
views
How to use a contract's mapping in test script?
Suppose there is a mapping mapping (address => bool) submitted.
If want to save something (like submitted[address] = true) in this mapping from test script while testing how can I do it??
- 665
2
votes
1
answer
334
views
Adding viaIR: true option Brownie
I'm getting
CompilerError: Stack too deep. Try compiling with `--via-ir` (cli) or the equivalent `viaIR: true` (standard JSON) while enabling the optimizer. Otherwise, try removing local variables. ...
2
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2
answers
105
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Best way to programmatically get an eth address
I am wondering what the best practice is to get an eth address and send it to an API.
Ideally, I am looking for a simple interface to grab the eth address and send it to the API and then send that eth ...
- 133
2
votes
1
answer
87
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Struct returns indexed numbers and property names
I'm using ethers and hardhat to run my React application. I want to pass an object as a parameter to a Solidity function. The function should map the object (struct) to the id provided as a property ...
2
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0
answers
37
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How to get the abstract model in smtlib2 format or z3 expressions from Solidity SMTChecker?
I want to get the abstract model in smtlib2 format or as Z3 expressions created by the SMTChecker. However, i cannot find any compiler switch or something to get the model. The SMTChecker ...
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2
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48
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Temporarily restricting access to your own funds
I want to do my personal banking in cryptocurrency because I want the customizability, convenience and freedom of money being open source software instead of being heavily limited by the huge variety ...
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2
votes
1
answer
94
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Dynamic array inside a struct in solidity
contract EventContract {
struct Event {
address organiser;
uint price;
uint totalTickets;
uint ticketsAvailable;
uint startDate;
uint endDate;
...
2
votes
2
answers
515
views
is there a tool for building calldata for calling methods?
I am trying to write a script to call the following method:
/// @notice Creates a proposal
/// @param _targets The target addresses to call
/// @param _values The ETH values of each call
...
- 23
2
votes
2
answers
86
views
How to take input from the user only once with the help of a function and then use it in all of the other functions?
Here I take input from the user in every function to perform the calculation but what if I wanted to take the two input numbers from the user only once and then perform all the rest of functions with ...
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2
votes
2
answers
319
views
How does the EVM internally revert the contract to the initial state when exceptions are present?
In error handling, assert and require statements revert the state of the contract to the initial state and then the transaction passes or fails depending on the code. I'm trying to understand how this ...
2
votes
2
answers
320
views
Given 2 transactions to my smart contact on the same block, how can I tell which came first within the contract?
My contract requires holding a history of all interactions to it. I have a hook for everything except tokens being sent to the contract — this requires a separate array of history from everything else ...
- 608
2
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2
answers
149
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Efficient way of verifying a sum of multiple numbers
If I have, let's say 1000 numbers or 10k numbers, and they all add up to 100 when combined, what would be the most efficient way to verify that in fact the sum of all of them is 100?
I was thinking on ...
- 711
2
votes
1
answer
795
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Hardhat multiple folders for compilation
Is there a way to provide multiple folders for compilation in hardhat config? I test my contracts with the foundry and all test contracts are under test/foundry folder so the written code in this ...
- 386
2
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0
answers
219
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Deploying on hardhat using gnosis-safe as deployer
Is there any approach to deploy smart contracts in hardhat using my gnosis safe as deployer?
I had a look over hardhat plugins but I haven't found anything.
Any idea?
- 131
2
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2
answers
2k
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How this honeypot token is able to fool the checkers? How does it figure out how the transfer function is called - via mined or simulated transaction?
I'm developing a scanner/checker for honeypot tokens and I was using it for a few days now to scan the BSC network. While using it I keep stumbling on one particular design many times a day, which is ...
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2
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ERC1155 wrapper to ERC721
I have seen a couple of wrappers/adapters from ERC1155 to ERC20 but no from ERC1155 to ERC721: https://github.com/gnosis/1155-to-20
Does anyone know any public implementation?
I'm thinking to ...
2
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0
answers
64
views
solidity - supportsInterface with ERC165 in the abstract contract
I have an abstract contract.
abstract contract Test is ERC165 {
function great1() public {
}
function great2() public {
}
function supportsInterface(bytes4 interfaceId) public ...
- 147
2
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0
answers
553
views
HardhatError: HH110: Invalid JSON-RPC response received: missing token when deploying to Görli (Gorli/Goerli) testnet
Summary
When I run yarn hardhat run scripts/deploy.js --network goerli, the following error is displayed in my terminal:
HardhatError: HH110: Invalid JSON-RPC response received: missing token
at ...
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2
votes
1
answer
80
views
Why does releasing a storage variable cost more gas than it saves?
I am experimenting on saving gas by releasing some storage on my smart contract.
In the smart contract there is a mapping, which i fill with data by calling the function setStorage. The other function ...
- 21
2
votes
1
answer
116
views
What is the purpose of returning values in state changing functions?
I'm confused, as far as I know you can't get the returning value of state changing value funcions (unless the function is invoked from a smart contract), so what is the purpose of the return true in ...
- 31
2
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0
answers
156
views
function call failed to execute with swapExactETHForTokens on pancakeswap
My friends, I am trying to create a function to swap WBNB vs tokens On pancakeswap. I can swap token vs token, But when I try to swap WBNB vs token, I'm stuck and get the error in the end of this post....
- 41
2
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0
answers
22
views
deployment cost different in solidity
contract A {
function b_1Y() public pure returns (uint) {
return 1;
}
}
contract B {
function b_1X() public pure returns (uint) {
return 1;
}
}
Deployment cost of A is much ...
- 1,145
2
votes
2
answers
511
views
How to check for emitted event inside solidity constructor when writing hardhat tests?
Say I have contract Foo:
contract Foo {
event OwnerAdded(address indexed owner);
address public owner;
constructor(address _owner) {
owner = _owner
emit OwnerAdded(owner)
}
How would I ...
- 1,408
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0
answers
28
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Why No Constant Linking?
Similarly to library linking
https://docs.soliditylang.org/en/latest/using-the-compiler.html?highlight=compiler%20options#library-linking
why is there no constant linking for the compiler?
The only ...
- 141
2
votes
3
answers
1k
views
How to get test ERC20 tokens on mumbai testnet?
How I can get DAI, USDC, WETH, or any other erc20 token for mumbai testnet ?
I am working on lending and borrowing platform so I need test tokens for that.
2
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1
answer
386
views
What is the gas refund for clearing out storage via SSTORE?
There is a lot of conflicting information due to the change in the gas refund mechanism from EIP-3298.
According to evm.codes the user will still be charged net 200 gas for clearing out a storage slot....
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2
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0
answers
73
views
Convert FunctionMessage into ABI string using Nethereum
I want to convert FunctionMessage objects into ABI. Is there any function in Nethereum library to do this work or should I do it using reflection ?
code example:
[Function("balanceOf", "...
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2
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1
answer
135
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Solidity Clones Contracts: How to save deployer as a storage variable which can be called in created clones?
I am using the OpenZeppelin Clones Library so that users of my dapp can create clones of my implementation contract. My dapp will be following the EIP-1167 standard.
For functionality, I will need to ...
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2
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1
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236
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What is the recommended waiting time between requestRandomWords and fulfillRandomWords calls in Chainlink VRF V2?
Recently, Chainlink published their VRF v2. The new VRF uses subscription management app. There is a delay between the requestRandomWords and fulfillRandomWords function.
On the Goerli test net, ...
2
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0
answers
28
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payable extension required?
I am writing a simple contract to replicate a voting session led by a president. The contract compiles correctly, however, I can't deploy it because of the following error: "Note: The called ...
2
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0
answers
94
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How to interact with smart contract using android(Kotlin)?
How to interact with smart contract via Kotlin? I'm able to interact with Web apps using react.js. But struggling to interact with android!
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1
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135
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Set metadata for Ethereun new token minted after deployment ERC 1155
i set a new contract with eRC 1155 on ethereum with 3 categories of 3 tokens (Id 1,2,3) and deployed it in the blockchain.
To have the possibility to mint new token i create a override function for ...
2
votes
1
answer
1k
views
Error: call revert exception
I keep getting this unhandled runtime error with my code:-
" Unhandled Runtime Error
Error: call revert exception [ See: https://links.ethers.org/v5-errors-CALL_EXCEPTION ] (method="...
