call other contract's external function , the error: The contract code couldn't be stored, please check your gas amount

Question

when I deploy a contract, the truffle frame told me this error：“The contract code couldn't be stored, please check your gas amount”。 the solidity code is:

1. Base.sol

   pragma solidity ^0.4.22; contract Base{ uint public num; event mint(uint n); constructor() public { }

   function Minit(uint _n) external returns (bool) {
       num = _n;
       emit mint(num);
       return true;
   }
   function getN() external view returns(uint result){
       result =  num;
   
   }
   

   }

2. Extend.sol

   pragma solidity ^0.4.22; import "./Base.sol"; contract Extend{ Base public base; uint public num; constructor() public { base = new Base(); base.Minit(10); }
   function setN() public{ num = base.getN();

    }
    function getN() public view returns(uint){
        return num;
    }
   

   }

3. I run these smart contracts in a private ethereum. the genesis.json is:

   {

   "config": {

   "chainId": 168,

   "homesteadBlock":5,

   "eip155Block":0,

   "eip158Block":0

   }, "alloc" : {},

   "coinbase" : "0x0000000000000000000000000000000000000000",

   "difficulty" : "0x400",

   "extraData" : "",

   "gasLimit" : "0xffffff",

   "nonce" : "0x0000000000000042",

   "mixhash" :"0x0000000000000000000000000000000000000000000000000000000000000000", "parentHash" :"0x0000000000000000000000000000000000000000000000000000000000000000", "timestamp" : "0x00" }

4. the truffle.js file is：

   module.exports = { // See http://truffleframework.com/docs/advanced/configuration // to customize your Truffle configuration! networks:{ live: { host:"127.0.0.1", port:8545, network_id:"168", from:"0xd31457ba4448cf4ec0c9b9e87e06d633cd9e5406", gas:6500000

        }
    }
   

5. the deploy script is:2_deploy_contracts.js

   var Extend = artifacts.require("./Extend.sol"); module.exports = function(deployer){ deployer.deploy(Extend);

}

6. go's verions

   go version go1.10 linux/amd64

7. geth's versions

   Geth Version: 1.8.15-stable Architecture: amd64 Protocol Versions: [63 62] Network Id: 1 Go Version: go1.10 Operating System: linux GOPATH=/home/hlf/Gopath GOROOT=/usr/local/go

so, I want to know why I failed. and What should I do?

---

Now, I found that if one contract call another contract's external function and this function have a returns value,the gas will be burned all, sample:

1. Base.sol

   pragma solidity ^0.4.22;

   contract Base{ address public owner; function Mint() payable external returns(uint){ return 1; } constructor() public {} }

2)Extend.sol

pragma solidity ^0.4.22;
import "./Base.sol";
contract Extend{
    Base public base;
    uint public es;
    constructor (address  _baseAdd) public {
        base = Base(_baseAdd);
    }
    function mint() public {
     es =   base.Mint();
    }
    function getES() public view returns(uint){
       return es;   
   }

}

when I call ExtendInst.mint() in truffle console, es = base.Mint() will consumes all the gas. why? And Is it can't use a contract's external function to return a value?

Answer 1

I think that you cannot deploy smart contract by using this code

base = new Base();

the error “The contract code couldn't be stored, please check your gas amount” will throw because web3.js lib cannot get the byte code of the smart contract.

You should deploy the contract base, and pass the contract address into contructor of the Extend contract

pragma solidity ^0.4.22;
import "./Base.sol";
contract Extend{
    Base public base;
    uint public num;
    constructor(address _base) public {
        base = Base(_base);
        base.Minit(10);
    }   
    function setN() public{
        num = base.getN();

    }
    function getN() public view returns(uint){
        return num;
    }
}

Or you should extend from contract Base as below

pragma solidity ^0.4.22;
import "./Base.sol";
contract Extend is Base {
    uint public num;
    constructor() public {
        Minit(10);
    }   
    function setN() public{
        num = getN();

    }
    function getN() public view returns(uint){
        return num;
    }
}