Questions tagged [assert]

An assertion is a statement, which aborts a program when it evaluates to false. Assert is typically used for debugging and situations which should never happen.

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Testing address(this) generates exception, how to obtain the correct value for address(this)

I have modified the following code from a michalzalecki website https://michalzalecki.com/ethereum-test-driven-introduction-to-solidity/ to test address(this): pragma solidity 0.5.16; import "...
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Fail with error 'TransferHelper: TRANSFER_FROM_FAILED', all gas used up

I'm trying to buy some CHY with USDT on Uniswap main net, fails with error 'TransferHelper: TRANSFER_FROM_FAILED', This is my failed tx link. This is a successful tx link from someone else. I notice ...
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23 views

Truffle script: how to run multiple assertions without stopping the program?

I am trying to run multiple assertion using a single script. My script stops after the first assertion: My output is: t$ truffle exec ts4_for_forum.js Using network 'development'. acc2 balance ...
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How to get smart contract assertion message thorugh web3.js? [duplicate]

I revert a transaction in my smart contract when a specific condition is met. For instance: function doMoneyLaundering(uint256 millionsOfDollars) public { ... require(...
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60 views

address payable[] public causing SWC 110 and execption state

This is the output of mythril ==== Exception State ==== SWC ID: 110 Severity: Medium Contract: XXXXXXX Function name: recipients(uint256) PC address: 2067 Estimated Gas Usage: 1089 - 1184 An assertion ...
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I want to understand something with BigNumber assertions

I have create a truffle project with a smartcontract and a test file. Here is an extract of the test file: expect(ret).to.be.bignumber.equal(new BN('42')); ret is a value returned by a smartcontract'...
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68 views

Truffle console: assert.equal, how to use exception for testing purposes?

I want to check the value returned by getName() function: pragma solidity >= 0.5.0 < 0.7.0; contract SimpleContract { string public name; constructor() public { name = 'abs'; } ...
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Are assertions removed in release build?

Are assert() removed in release build? Please show an authoritative document documenting that they are removed or no removed.
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572 views

Read message of require / revert statement in app.js

In my App.js I have called the smart contract function and the require statement in the function is not satisfied, so how do I get the message of that require statement in my App.js?
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573 views

How to handle require/revert/assert errors properly

I'm trying to find an easy pattern to revert/rollback a write transaction. The first idea was to log a GenericErrorEvent but then I noticed that it will never be emited if any require/revert/assert ...
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140 views

Access require message

I am using JavaScript to run some tests on my solidity contract. Since solidity ^0.4.22 you can have a message in require such as: function Hello { require(msg.sender == 0x001234, "msg.sender ...
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348 views

How to use require() with stings

I am trying to run this code on remix IDE: pragma solidity ^0.4.24; contract Aa { string public result; function feedData(string _result) public { require(_result = "e" , "...
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40 views

Contract design by contract -> correctness and maximum gas consumption

This question is a general design question that regards contract correctness and the functions I list here are just examples. As I develop on Ethereum, it becomes aparent to me that it might be ...
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605 views

Better ways to test bytes32 type using truffle testing framework

small quick question, when I store a bytes32 and retrieve it from truffle console, why is it showing in 64 bits? Ex: 0x74657374737472696e6700000000000000000000000000000000000000000000 because this ...
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811 views

Why not use require() in place of assert()?

Even though require() is used substantially more than assert(), there are places where assert() gets used. One example would be in the widely adopted SafeMath library by OpenZeppelin: function add(...
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440 views

Handling require/assert failure errors correctly from a Node.JS app?

I have a getter function in my smart contract that returns one of the string values in statically defined string array. Upon entry to the function, it does a bounds check on the incoming index using ...
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203 views

Call a zero-initialized variable of internal function type

I was reading solidity documentation about when an assert-style exception is generated. In the 6th point it says: "If you call a zero-initialized variable of internal function type." I don't ...
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147 views

Issue with Assert statement in solidity

I am probably missing something very obvious but I cannot get the simplest assert statement to work! What am I doing wrong? My goal is to simply confirm that I am within a start date and end date ...
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797 views

Remix Warning : Assert

I am trying to compile a contract on remix and have run into the following warning : Use assert(x) if you never ever want x to be false, not in any circumstance (apart from a bug in your code). ...
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137 views

'Assert' and 'require' atomicity while internally calling another contract

contract one{ unint number; function saveNumber(unint _number){ number = _number; } } contract two{ function callOtherFunctionAndAlsoTransferFunds(){ oneContract = one('contractaddress'); ...
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301 views

Control structure with truffle (assert and require)

When I'm trying to deploy contracts that contain assert and require using truffle I receive Error: Undeclared identifier. e.g: pragma solidity ^0.4.8; contract Owned{ address public owner = ...