Support for EIP-1559

[kclowes]

• Version: v5.14+

What was wrong?

It looks like EIP-1559 is coming up soon (maybe in the London hard fork), so we'll need to update web3py to support it. This is a placeholder issue that will likely get broken down into a few issues.

How can it be fixed?

From a high level, it looks like we need to change our transaction object:

• New fields in the transaction:
  • fee_cap_per_gas
  • max_miner_bribe_per_gas
• Remove gas_price (will probably need to keep it in in v5 and then need to make a note to remove in v6)

BlockData will need to change as well:

• Add base_fee field
• move gas_limit to gas_target (In v5, we'll need to keep both gas_limit and gas_target and remove gas_limit in v6).

Also probably simplifies (possibly removes the need for) our gas price strategies.

@abdelhamidbakhta or @pipermerriam let me know if I'm missing anything!

[AbdelStark]

@kclowes Thank you very much for starting looking at this.
You don't have to remove gas_price. There is no plan/timeline to remove legacy transaction support for the moment. @timbeiko can you confirm ?
Also IMO the move gas_limit to gas_target is not necessary. It is a nice to have though.
Otherwise the high level approach makes a lot of sense.

[timbeiko]

No plan on removing legacy transactions in the foreseeable future!

[kclowes]

There are a few issues open that still need some work, but initial MVP work on 1559 support has been completed. See #2065 and #2066.