Truffle deployed contracts can't be verified through Etherscan

Question

I am faced with the problem the truffle generates a different bytecode than solcjs (local compiler) and also than Remix (online compiler). And therefor I can't verify my contracts throght Etherscan (see https://etherscan.io/verifyContract)

My enviromnment:

OS: Ubuntu 15.10

$ uname -a
Linux sasha 4.2.0-42-generic #49-Ubuntu SMP Tue Jun 28 21:26:26 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux

$ truffle version
Truffle v3.2.4

$ solcjs --version
0.4.11+commit.68ef5810.Emscripten.clang

What I tried to do:

1) I created a simple smart contract Ownable:

pragma solidity ^0.4.11;
contract Ownable {
    address public owner;
    function Ownable() {
        owner = msg.sender;
    }
    modifier onlyOwner {
        if (msg.sender != owner) throw;
        _;
    }
    function transferOwnership(address newOwner) onlyOwner {
        if (newOwner != address(0)) {
            owner = newOwner;
        }
    }
}

2) Init a new truffle project and copy Ownable.sol into "contract" folder.

So the structure of project must be the following:

test-comtract
-- contracts
   -- Ownable.sol
-- migrations
   -- 1_initial_migration.js
   -- 2_deploy_contracts.js
-- test
truffle.js

3) Compile the truffle project:

$ cd test-contract
$ truffle compile

After compilation "build" folder will be created.

4) Go to the "build" folder and search Ownable.json file there. In this file search the generated bytecode in "unlinked_binary" attribute. The value is shown below:

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

5) Tried to compile through Remix online compiler. https//ethereum.github.io/browser-solidity/#version=soljson-v0.4.11+commit.68ef5810.js&optimize=true

The result of the compilation is shown below:

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

6) Tried to compile by helps with solcjs:

$ cd test-comtract/contracts
$ solcjs --optimize --bin Ownable.sol

In "test-comtract/contracts" folder will be created the file "Ownable.sol:Ownable.bin"

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

RESULT: The SolJS bytecode is identical to the Remix bytecode but different from the truffle bytecode.

7) Also I deployed the Ownable.sol through truffle to the Ethereum (TEST_NET). You may see it by follow this URL:

https://ropsten.etherscan.io/address/0x6c8e1b321ce94b12069222b543558d4159527ecd

Maybe somebody is faced with the such problem. I'll be very appreciate to hear any versions why it is happing. Maybe this is a known bug of the Truffle framework. In google I found some more articles describes the similar problems, but nobody suggest a solution. I very need help

Thanks in advance!

-- Alex

Answer 1

You are facing this issue because there is a problem with compiler optimization in solc/truffle-compile. Etherscan does not support the compilation of contracts.

Here's the link to it to doc which you might find interesting. 

https://github.com/trufflesuite/truffle-compile/blob/331809c73389f27f9dda40229061bb75b18f27ca/index.js#L70