Non ABI-standard return value of get_deposit_count of deposit_contract

[daejunpark]

What's wrong?

The return value of the get_deposit_count function of deposit_contract does not conform to the ABI encoding, having incorrect zero-padding, due to a Vyper compiler bug.

How to reproduce?

For a quick reproduction of the buggy behavior, just add the following line at the end of test_deposit_tree (inside the for loop):

registration_contract.functions.get_deposit_count().call()

(A more meaningful test would be to check the return value is equal to the loop index i, the number of deposit invocations made.)

Then you will get the following exception:

eth_abi.exceptions.NonEmptyPaddingBytes: Padding bytes were not empty: b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00 '

which is generated by eth_abi/decoding.py. (Note that the last character is an ascii character of b'\x20.)

How to fix?

Well, wait until the compiler bug is fixed, and update the Vyper compiler version. :)

Also, add some tests for (or have the existing tests to invoke) get_deposit_count, to detect further regressions.

[JustinDrake]

Congrats on finding that compiler bug! While we're at it, I suggest bundling in #1279 when we do the fix.

[JustinDrake]

Closing in favour of #1362 :)