Lesson 7: Incompatible Solidity Version

[danmas95]

In the "Smart Lottery" Project I'm having trouble with the LinkToken.sol smart contract. The file should be compiled with pragma solidity ^0.4.11; but a compile error is rised by Brownie. The error is IncompatibleSolcVersion: Brownie only supports Solidity versions >=0.4.22.

On github repos (chainlink-mix and chainlink) there is only the v0.4 version available of LinkToken.sol file.

I tried to manually add all the files necessary to compile that specific smart contract but it's not a good practise and I had lot's of troubles to migrate everything to solidity ^0.6.0 (the version used in the course project).

Can you suggest me a solution?

Thanks.

[cromewar]

Hello @danmas95
That's strange as brownie 1.17.1 actually compiles that contract without problem, you could try to can downgrade your brownie version to one compatible with 0.4.11; like 1.16...
But if you want a simpler solution just use LinkToken on version 0.6.0 which could be found here. Just replace the contract with this one.

Best regards, Cromewar.

[cromewar]

@PatrickAlphaC could you give us a tip on this one?

[danmas95]

I manually copied OpenZeppelin and Smartcontractkit folders into .brownie in WSL and didn't recognized it. It still looks for the folder in the Windows path. Strage, very strange.

[cromewar]

Actually those files will appear automatically after doing a compile installing into brownie folder, so coping directly to that path wont work, that's why I suggested you to clone the repo and compile, because those files should be generated by brownie, so I recommend you to delete them and compile a project using brownie on WSL.

[danmas95]

[UPDATE] - Current situation

I deleted the project on WSL and started a new one, as you suggested. I copied every single file from "my version" of the project (I watched the video course and coded along with Pat, writing here and there a couple of notes, so I prefered to reuse my code).

I compiled via brownie compile and NO ERRORS came out!! Incredible!

Just a couple of warnings came out, to be honest. In particular:

1. WARNING: Unable to compile smartcontractkit/[email protected] due to a NamespaceCollision - you may still be able to import sources from the package, but will be unable to load the package directly.

2. WARNING: Unable to compile OpenZeppelin/[email protected] due to a CompilerError - you may still be able to import sources from the package, but will be unable to load the package directly.

Anyway...it seems everything fine (at the moment, at least...).

So...THANK YOU! You really helped me.

Now...I would like to know why the problem came out on Windows and how can be solved...but for now, I'm happy with the "WSL Solution".

[cromewar]

WARNING: Unable to compile smartcontractkit/[email protected] this just means you have two files which are the exact same, brownie is saying you have the local file on your project and the one which comes from Github, but you don't have to worry about.

.I would like to know why the problem came out on Windows and how can be solve

I have no idea, I a lazy answer is that windows manages packages very poorly and it's a mess managing python stuff, but a concrete answer is something out of my limited knowledge-

I'm glad the problem is now solved for you, I'll close this thread now. Feel free to make any other questions you want.