Allow block identifier for Contract.estimateGas

[palango]

What was wrong?

Related to Issue #1011 and PR #1046

How was it fixed?

Adds block_identifier to Contract.estimateGas(...)

Todo:

• Add entry to the release notes

Cute Animal Picture

[wolovim]

Thanks for the PR @palango. Can we get one or more tests documenting this change?

[palango]

Thanks for the PR @palango. Can we get one or more tests documenting this change?

Sure, I'll add some tests, but let me know if you want something particular.

[palango]

@marcgarreau I wonder how #1046 actually works, the eth-tester still doesn't have a block_identifier parameter: https://github.com/ethereum/eth-tester/blob/035dde2c4ebc10a205748b37b940cb519251d9da/eth_tester/main.py#L431

Do I need to add that there?

[wolovim]

Coming up to speed on the block identifier... just curious, if you're testing this locally, are you using parity/openethereum? Looks like the feature is available on that client, but not geth.

If we follow the precedent set by #1046, then we'd skip the implemention in eth-tester, and document that in the tests similar to this xfail.

[palango]

Coming up to speed on the block identifier... just curious, if you're testing this locally, are you using parity/openethereum? Looks like the feature is available on that client, but not geth.

Yes, openethereum supports it, but geth not. See ethereum/go-ethereum#2586

If we follow the precedent set by #1046, then we'd skip the implemention in eth-tester, and document that in the tests similar to this xfail.

I remember vaguely that I read somewhere that py-evm supports a block identifier on this call. I f so, it would be nice to support it.

[wolovim]

Had a quick chat with @carver who confirmed py-evm does have support for the block identifier, and that eth-tester would need to be updated to that effect. Are you interested in giving that a shot?

[palango]

Are you interested in giving that a shot?

I don't have time for that at the moment. I'll come back if that gets better.

[wolovim]

(started work on this today)

[wolovim]

There's a PR up in eth-tester which satisfies these failing tests (and hopefully doesn't create any new ones).

[carver]

We can try to get new eth-tester released on Monday. In the meantime, it is possible to pin a requirement to a github-hosted commit, if you want to try it out. @marcgarreau

[carver]

Great! (to merge after the eth-tester dependency can be pulled from pypi again)