Handle messages that would result in execution error

[aakoshh]

Apparently if there is no gas limit set on a message whatsoever, the execute_message method of the FVM fails, instead of returning an ApplyRet. I'm not sure how Lotus handles it, but we can do a multitude of things

• encode the result as an ApplyRet in the FvmExecState, or
• introduce a special error case checked in the interpreters (both query and signed are affected), or
• use ABCI++ to filter such messages in the prepare_proposal, and reject such blocks in the process_proposal method

Not sure which is the best approach yet 🤔

[aakoshh]

I actually started with option 1) in consensus-shipyard/fendermint#128, but later thought option 3) would be better. Then I realised that the way I discovered this problem was with with an eth_call, which would not be filtered out with ABCI++

So the only option is to handle it with an error, and perhaps penalize the validator who put it into a block, or also use ABCI++ to never vote for a block which contains such messages.

We must also add this check to the check interpreter to get fast feedback, although, again, queries would not be affected by that.