<contract_func>.call modifies user input

[charles-cooper]

What was wrong?

When a block hash is supplied as the block identifier, web3.py replaces the block param with that block's number (cf.

web3.py/web3/contract.py

Line 1343 in 652650d

return web3.eth.getBlock(block_identifier)['number']

). This can result in eth_call being called on a different block than the intended block in the case of a reorg.

How can it be fixed?

1. Raise an exception if a block hash is supplied to call instead of modifying user input
2. Make an EIP to change the JSON RPC to accept block hash in addition to QUANTITY|TAG. Then just pass the block hash through instead of changing user input.

[pipermerriam]

Raise an exception if a block hash is supplied to call instead of modifying user input

I'm in favor of this approach and this would be a breaking change that could squeek into v5

[charles-cooper]

Make an EIP to change the JSON RPC to accept block hash in addition to QUANTITY|TAG. Then just pass the block hash through instead of changing user input.

Cf. ethereum/EIPs#1898, could be a ways until this is implemented by nodes though.