contract-debugging Solc – How to Install Old Solc Compiler Versions

contract-debuggingsolcsolcjs

I would like to compile older versions of solc contract source code using a solc compiler on my local machine. Is there a website from which to download old solc compilers?

Google revealed a GitHub of old solcs, but I tried using node to run the .js. files without success (could be using this wrong).

Best Answer

I maintain a Python library called py-solc-x that allows you to install and use multiple versions of solc at the same time. It supports versions >=0.4.11. I've included some code examples below to give an idea of how it works.

Installing a new version of solc:

>>> from solcx import install_solc
>>> install_solc('v0.4.25')

Checking installed versions and versions can be installed:

>>> from solcx import get_installed_solc_versions, get_available_solc_versions
>>> get_installed_solc_versions()
['v0.4.25', 'v0.5.3', 'v0.6.0']
>>> get_available_solc_versions()
['v0.6.0', 'v0.5.15', 'v0.5.14', 'v0.5.13', 'v0.5.12', 'v0.5.11', 'v0.5.10', 'v0.5.9', 'v0.5.8', 'v0.5.7', 'v0.5.6', 'v0.5.5', 'v0.5.4', 'v0.5.3', 'v0.5.2', 'v0.5.1', 'v0.5.0', 'v0.4.25', 'v0.4.24', 'v0.4.23', 'v0.4.22', 'v0.4.21', 'v0.4.20', 'v0.4.19', 'v0.4.18', 'v0.4.17', 'v0.4.16', 'v0.4.15', 'v0.4.14', 'v0.4.13', 'v0.4.12', 'v0.4.11']

Setting the current solc version using a pragma statement:

>>> set_solc_version_pragma('^0.4.20 || >0.5.5 <0.7.0', check_new=True)
Using solc version 0.5.8
Newer compatible solc version exists: 0.6.0

Related Solutions

Windows Solc Installation – How to Install Solc Compiler on Windows 8

One relatively easy solution is to install node.js and use the solc npm package. I used it myself when I initially started playing with ethereum contracts and it was a snap to set up.

Here are the steps -

install the latest version of node.js
create a folder for the project
add solc package to your package.json file, or use the following package file -

{ "name": "eth_compiler", "version": "0.0.1", "engines": { "node": ">=7.0.0", "npm": "^3.0.0" }, "dependencies": { "solc": "^0.4.7" } }
run npm install in the folder
add a small js script to the folder (compile.js) - it will receive the contract file name and output the abi/code files you need.

Here's a example -

var solc = require('solc');
var fs = require('fs');

var inputFilePath = process.argv[2];
var outputPath = process.argv[3];

// note - using the synchronous version of the file system functions for simplicity and because the async version isn't really needed in this case
var contractSolidity = fs.readFileSync(inputFilePath , 'utf-8');
if (!contractSolidity)
    return console.error('unable to read file: ' + inputFilePath );

var output = solc.compile(contractSolidity, 1);
for (var contractName in output.contracts) {
    var abi = output.contracts[contractName].interface;
    var code = output.contracts[contractName].bytecode;
    fs.writeFileSync(outputPath + '/' + contractName + '.abi', abi, 'utf-8');
    fs.writeFileSync(outputPath + '/' + contractName + '.code', code, 'utf-8');
}

once you have that file, you can simply execute the following command in the new folder - node compile [inputFilePath] [outputPath]

and it should generate the compiled files.

Note: I did test it locally and managed to compile a contract so I believe it should work but it's worth mentioning that I have both party & cpp-ethereum installed on my machine (parity wasn't running at the time of this script's execution).

[Ethereum] Switch solc compiler versions

You may be interested in the new truffle feature, the ability to specify your solidity compiler, https://github.com/trufflesuite/truffle/releases/tag/v5.0.0#user-content-what-s-new-in-truffle-v5-truffle-compile-solidity-specify-your-compiler-version.

As for manually switching between the 2, I think docker would be your best bet.