How do I find the exact solidity compiler version used by truffle?

Question

I'm trying to verify a contract I have compiled and deployed onto the network using Etherscan. The contract was compiled using truffle. How do I work out exactly which version of the solidity compiler to select on Etherscan?

Answer 1

I'm running Truffle 3.4.11 and running just: truffle version gives me the Solidity version as well:

truffle version                                                                                                                                                           
Truffle v3.4.11 (core: 3.4.11)
Solidity v0.4.15 (solc-js)

Answer 2

I managed to find a hacky way of doing this. Note - I was looking for more than just the version of solc. I was looking for the actual build of the compiler that solc was using (ie the commit used, night build number etc) so that I could could select it on EtherScan.

I have truffle installed globally so I ran which truffle which allowed me to eventually find (following symlinks) where truffle was stored on my mac: /Users/username/.nvm/versions/node/v7.7.3/lib/node_modules

From here it was easy to locate where the solc installation used by truffle is also stored. Relative to the previous path it would be in ./truffle/node_modules/solc

At this point - if you just want the version of the solc package you can look in package.json

If you want to go further and find the specific compiler version (like me) then take a look in wrapper.js and look for the var version variable declaration. It turns out this is a function which will return the compiler version name being used. Simply console.log(version()); on the next line and when you next run truffle test or truffle compile the solidity compiler build will be output into your console. For me this looked like:

var version = soljson.cwrap('version', 'string', []);
console.log(version());

Remember to return the wrapper.js file to its original state after you have got the info you need.

Note: This is a very hacky way of doing it. There's probably a better way but it was the first method I stumbled on. Even then - it didn't even help me get the contract verified on Etherscan, anyway.

Answer 3

The easiest way to get compiler version with truffle is to find it in your project directory ./build/contracts/YourContractName.json near the bottom of the file. It looks like,

 "compiler": {
    "name": "solc",
    "version": "0.4.18+commit.9cf6e910.Emscripten.clang"
  }

Answer 4

You can look at the file ./node_modules/solc/package.json and see something like "solc@^x.y.z" where x.y.z is the version number that is being used.

Answer 5

If you have npm installed with the -g flag, you can do this (omit the -g if you have it installed locally)

$ npm -g ls | grep solc └─┬ [email protected]

That should be your version.