Fix initialize_beacon_state_from_eth1 previous_version

[hwwhww]

Thank @tbenr for finding this error!

[djrtwo]

On second thought, I’m not convinced what correct behavior for this versioning is.

• compute_domain() in process_deposit is “fork agnostic” and is always based on GENESIS_FORK_VERSION
• There is no prior fork when initializing a chain so the use of ALTAIR does not immediately seem correct as there is no Altair history
• The primary usecase of previous_version is to verify signatures from the previous fork, but there is no previous history prior to the genesis in this case. The only prior history is kind of the deposits that use GENESIS_FORK_VERSION.

Because of the above, I’d argue to either initialize it to GENESIS_FORK_VERSION because deposits use this OR just initialize it to MERGE_FORK_VERSION which I think is a bit more semantically correct when looking at how the state in initialized in phase 0.

The altair analogue of this function uses GENESIS_FORK_VERSION so double MERGE_FORK_VERSION isn’t consistent unless we change the function in altair as well.

[tbenr]

my two cents (just because I raised the problem).
the second option seems preferable to me:

current_version=MERGE_FORK_VERSION,  # [Modified in Merge]
previous_version=current_version

I was also exploring the idea about introducing a non-configurable constant NO_FORK_VERSION=Version('0x00000000'). Using this should maintain phase0-MainNet compatibility but I guess brakes pahse0-devnets.

[hwwhww]

My institution was making it more like a mainnet real case, but you convinced me that MERGE_FORK_VERSION is better for the testing context.

If possible, I'd like to also change Altair initialize_beacon_state_from_eth1 to using previous_version=ALTAIR_FORK_VERSION.

Note: it has nothing to do with the mainnet consensus, just for testing.

[hwwhww]

@djrtwo @tbenr

I changed it to previous_version=current_version.

[djrtwo]

Agreed that it's reasonable to adjust the altair function as well.

This affects not only testing, but also testnets/networks that deploy their genesis from altair logic. I don't think we have any such nets today, so it's okay to introduce this change