Upgrade abi coder to fix solc 0.4.x edge case

[ryanio]

In ethers-io/ethers.js#891 (comment), @ricmoo notes that he released a new version of the ethersproject abi coder that contains a "loose" reader for decoding logs for certain contracts built with solc 0.4.x.

This is a tracking issue to upgrade the dependency in web3-eth-abi here so users can read these contracts (some used actively on mainnet) without future issue.

[spacesailor24]

Hopefully I'm just doing something incorrect here, but upgrading @ethersproject/abi to 5.0.4 (as mentioned here) doesn't actually solve the issue mentioned when testing using this test repo.

To make sure my testing steps are valid, here is what I did:

1. Update @ethersproject/abi version to 5.0.4 here
2. rm -rf node_modules && npm i
3. Then just to make sure, I also ran Step 2 in the web3.js root dir
4. npm run build in web3.js root dir
5. cd into above mentioned test repo
6. yarn which installs version ^1.2.8 of web3
7. npx truffle test receive following output:

...
1 passing (2s)
  1 failing

  1) Contract: Simple
       fires external event:
     Error: data out-of-bounds (length=36, offset=64, code=BUFFER_OVERRUN, version=abi/5.0.0-beta.153)
...

8. Update web3 dependency from ^1.2.8 to /local/path-to/web3 in package.json
9. rm -rf node_modules && npm i
10. npx truffle test receive following output:

...
  1 passing (1s)
  1 failing

  1) Contract: Simple
       fires external event:
     Error: data out-of-bounds (length=36, offset=64, code=BUFFER_OVERRUN, version=abi/5.0.4)
...

And to solidify that the updated @ethersproject/abi was used, you can see in the last line of the provided outputs, at the very end:

Using web3.js version ^1.2.8: ...version=abi/5.0.0-beta.153)

Using updated local web3.js: ...version=abi/5.0.4)

[spacesailor24]

Also #3738 seems to be related?

[Patil2099]

Can I work on this issue? I would love to work on this issue.

[GregTheGreek]

@Patil2099 what kind of timeline do you think this would take you?

[remon-nashid]

I confirm @spacesailor24's finding that upgrading abi coder to 5.0.4, or even the latest release, does not fix the decoding issue.

[ricmoo]

Are you making sure to pass true in for the optional allowLoose parameter in the .decode method? Keep in mind you should only allow this for events as it could expose exploits if loose parsing is allowed on function data...

[ricmoo]

(See: https://github.com/ethers-io/ethers.js/blob/master/packages/abi/src.ts/abi-coder.ts#L110)