Staking – How to Get List of All Blocks Proposed by a Validator

Validators will need to run execution layer (EL) clients because consensus layer (CL) clients don't create blocks with transactions and execute smart contracts.

There is more discussion at: https://old.reddit.com/r/ethstaker/comments/vv80qf/help_me_understand_why_technically_could_a/

This really is no different from how things work now in PoW, just that the consensus code is inside the EL in PoW. Every execution client comes with consensus layer code for PoW and PoA included. That 1:1 relationship continues, just that now the consensus is in an external client.

Also note that not everyone that is running a client like Geth today, is a miner.

I am failing to see how there can be a fork, if only one validator is selected during a slot to propose a block.

Ignoring slashable offenses (i.e., producing two conflicting blocks at the same slot), each slot can have either zero or one block.

On the Ethereum Beacon Chain (a.k.a "eth2"), we call any slot without a block a "skip slot". Skip slots will happen if the elected block proposer fails to disseminate a valid block for whatever reason (offline, eclipsed, etc).

When a block producer produces a block for some slot s, they get to choose the value for the block.parent_root. Generally, the proposer will choose the block at s - 1. However, if s - 1 is a skip slot, the proposer will select the latest non-skipped slot.

So, let us imagine the following scenario:

• There is a block at slot 1
• The block at slot 2 was published to only a small subset of the network.
• The block producer for slot 3 did not see the block at slot 2, therefore it uses the block at slot 1 for the block.parent_root.

A node on the network which observed all of the blocks will have the following block tree:

  1
 / \
2   |
    3

The blocks at slots 2 and 3 both reference the block at slot 1 as their parent and are therefore conflicting. There is a fork.