encode_packed produces wrong output

[krisbitney]

Version
2.0.0

Platform
Darwin (mac os) M1 apple cpu

Description
the abi.encode_packed function does not produce the output described in the Solidity spec.

A negative i16 -1 seems to be interpreted by ethers-rs as a uint256.

types: [ "int16", "uint48" ]
values: [ "-1", "12" ]
ethers-js: "0xffff00000000000c"
ethers-rs: "0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff0c"

Another example where the packages disagree:

types: [ "uint256", "uint256" ]
values: [ "8", "16" ]
ethers-js: "0x00000000000000000000000000000000000000000000000000000000000000080000000000000000000000000000000000000000000000000000000000000010"
ethers-rs: "0x0810"

[DaniPopes]

Please see #2225 and the docs of the function.

[krisbitney]

Please see #2225 and the docs of the function.

Thanks. I just reviewed these. It sounds like people are not concerned that the ethers-rs implementation differs from the Solidity implementation, because the limitations of the ethers-rs implementation are known (e.g. can't distinguish between uint sizes). Is that an accurate summary?

The function's docs says it has "the same behavior as it's Solidity counterpart", so that is why I expected the same output.

[DaniPopes]

Yeah, the biggest limitation is that we are delegating most of the ABI encoding functionality to an external crate (ethabi), which is fine until we want to add new functionality to it, like encode_packed, which requires a different API.. I think this is a goal for 3.0 tho