Compile errors on sample project in Truffle 3.0.2

Question

I tried to compile some smart contracts in truffle 3.0.2 (which works without problems in browser solidity and even older versions of truffle) and got compile errors. So I created a sample truffle project with

truffle init

and launched truffle compile:

$ truffle compile
Compiling ./contracts/ConvertLib.sol...
Compiling ./contracts/MetaCoin.sol...
Compiling ./contracts/Migrations.sol...
Error compiling:

Could not find expected contract or library in '/home/ubuntu-user/meta/contracts/MetaCoin.sol': contract or library 'MetaCoin' not found.
Compiliation failed. See above.

I suppose truffle init just was not updated for the new project structure. Trouble is, I do not know what that structure is supposed to be. I have read the documentation and upgrade guide, but it seems outdated and I was not able to get a clue about the problem. Does anyone have any idea, or maybe an idea for a tool that actually reduces complexity when dealing with smart contracts?

Answer 1

Can you upgrade Truffle to 3.0.5? The best way is to completely uninstall Truffle and then reinstall it.

The issue here is that the solidity compiler added breaking API changes between versions 0.4.8 and 0.4.9 -- a minor version change, a big no no. This invariably broke Truffle, and we had to scramble to fix it.

Please give the new version a try. It should fix your issue.

Answer 2

TL;DR update troufle to the newest verison or at least 3.0.4.

This is caused by solcjs breaking change in version 0.4.9. Truffle fixed the version at 0.4.8 in versions > 3.0.4