fix(l2): prover_server eth_estimateGas reverts

[fborello-lambda]

Motivation

There was a bug with block 288 while using the prover_server in dev mode. While debugging the problem, i faced with several possible problems regarding gas estimations.

At the end, the problem was caused by how the calldata was structured. I am not fully aware of the root cause, since it happened just with blocks higher than 288 == 0x120.

To replicate the issue, we can send an eth_estimateGas request:

 curl -X POST \ 
  http://localhost:8545 \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "method": "eth_estimateGas",
    "params": [{
      "to": <OnChainProposer Address>,
      "input": "0xcae120a6000000000000000000000000000000000000000000000000000000000000012300000000000000000000000000000000000000000000000000000000000000e000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000000",
      "from": <Verifier Address>,
      "value": "0x0"
    }],
    "id": 1
  }'

If we change the 123 with a number <=120 we will get a custom error message triggered by the require statements in the OnChainProposer.sol, otherwise we will get a message that says: "reverted: unknown reason".

Description

• Build the calldata in order
• Change min with max in the calc_gas_limit() function
• Do the as_u64() after checking the number to avoid panics
• The field gas in an eth_estimateGas request is optional, if we set it to 0 in the request, the highest_gas_limit would have been 0, now with the change, if the gas is 0, the highest_gas_limit is equal to the block.gas_limit.