"VM Exception while processing transaction: invalid opcode" only with Byzantium hardfork

Question

i'm testing my Smart Contract with Truffle and Ganache, everything works fine while using hadfork version "Petersburg", but when i switch to Byzantium i receive this error while truffle performs deploy:

Compiling your contracts...
===========================
√ Fetching solc version list from solc-bin. Attempt #1
> Compiling .\contracts\Migrations.sol
> Compiling .\contracts\MyContract.sol
√ Fetching solc version list from solc-bin. Attempt #1
> Artifacts written to C:\Users\[...]\AppData\Local\Temp\test-202032-8352-17dkmqb.vs9r
> Compiled successfully using:
   - solc: 0.5.17+commit.d19bba13.Emscripten.clang

Error: Returned error: VM Exception while processing transaction: invalid opcode    at PromiEvent (C:\Users\User-PC\AppData\Roaming\npm\node_modules\truffle\build\webpack:\packages\contract\lib\promievent.js:9:1)
    at TruffleContract.setCompleted (C:\Users\User-PC\AppData\Roaming\npm\node_modules\truffle\build\webpack:\packages\contract\lib\execute.js:169:1)
    at Migration._deploy (C:\Users\User-PC\AppData\Roaming\npm\node_modules\truffle\build\webpack:\packages\migrate\migration.js:93:

Truffle and Ganache are both updated to the latest version. i'm using web3 1.2

The Smart Contract is ok, i also did a lot of test and debuging on remix.

Any suggestion?

Answer 1

IIRC, solc 0.5.17 is pre-Byzantium and you need to transition to 0.5.2? (not 100% sure which one). Perhaps a kind soul will chime in with the exact version cutoff or else check the release notes for the first release with Byzantium support.

You can instruct truffle to use a specific solc version truffle-config.json. You may have to refactor the contract source code to achieve a successful compile with a newer compiler.

Hope it helps.