I've deployed my smart contract to Rinkeby test net. The "addProject" function works fine.

But when I try the "addProjectFile" function I got error.

"Error: gas required exceeds allowance or always failing transaction"

The code:

pragma solidity ^0.4.18;

contract MyProjectManger {
  address public owner;
  mapping (uint => MyProject) public myProjects;

  uint projectIndex;
  mapping (uint => uint) public projectFileIndexes;

  struct File {
    string url;
    string fileHash;

  struct MyProject {
    bytes32 id;
    string name;
    mapping (uint => File) projectFiles;

  function MyProjectManger() public {
    owner = msg.sender;

  modifier onlyOwner {
    require(msg.sender == owner);

  function addProject(bytes32 id, string name) public onlyOwner returns(uint projectId) {
    projectId = projectIndex;    
    myProjects[projectIndex] = MyProject(id, name);

  function addProjectFile(string url, string fileHash, uint projectKey) public onlyOwner returns(uint fileId) {
    uint projectFileIndex = projectFileIndexes[projectKey];
    MyProject storage project = myProjects[projectIndex];    
    require(project.id[0] != 0);

    fileId = projectFileIndex;
    project.projectFiles[projectFileIndex] = File(url, fileHash);    

  function remove() onlyOwner public {

  // to receive ether
  function() payable public { }


I did get "Gas requirement of functions" warnings for those two addXXX functions. But I don't understand, I don't have loops in those two functions, why gas requirement should be an issue?

  • I was able to deploy the contract. Not sure what your gas limit hit was, but make sure to set your gas limit to 600k. ropsten.etherscan.io/tx/… – ReyHaynes Mar 16 '18 at 3:08
  • @ReyHaynes, thanks. It did deploy. But I can't call one of the function... I've updated the question. – Allen Zhang Mar 16 '18 at 7:11
  • You're not storing the id correctly, the code breaks on the require inside the addProjectFile function. – Gabe Mar 16 '18 at 9:24
  • @Gabe, I changed that line to "require(project.id[0] != 0);" but same result.... – Allen Zhang Mar 16 '18 at 9:33

There is no error/mistake in the contract. Try compiling the contract again.

FYI, I tried deploying the contract and it was successfully deployed at https://rinkeby.etherscan.io/address/0x94677eac807ccd5fd1f686d687c3cf47ada3b97d#code

  • It did deploy. But now the problem is that I can't call one of the function.... – Allen Zhang Mar 16 '18 at 7:10

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