Finalized always return block 0

[kamiyaa]

Component

Anvil

Have you ensured that all of these are up to date?

• Foundry
• Foundryup

What version of Foundry are you on?

forge 0.2.0 (4f00ec6 2024-02-17T00:16:39.754919679Z)

What command(s) is the bug in?

No response

Operating System

Linux

Describe the bug

JSON RPC call to get_block(BlockNumber::Finalized) always returns the 0th block for some reason.

[mattsse]

how should we handle these tags, use the latest or do a mod 32 on the chain height?

[sveitser]

We've also ran into this. I think for us both would but fine, but if it's not too cumbersome: how about mod N with N being a parameter passed to Anvil at startup?

[mattsse]

I think we should do:

• configure an epoch number, default 32 blocks
• make it configurable via CLI

[mattsse]

@yash-atreya adding this to anvil cli args would be simple

turns out we already do a mod 32:

foundry/crates/anvil/src/eth/backend/mem/mod.rs

Lines 1487 to 1502 in ce22450

	BlockNumber::Safe => {
	if storage.best_number > (slots_in_an_epoch) {
	*storage.hashes.get(&(storage.best_number - (slots_in_an_epoch)))?
	} else {
	storage.genesis_hash // treat the genesis block as safe "by definition"
	}
	}
	BlockNumber::Finalized => {
	if storage.best_number > (slots_in_an_epoch * U64::from(2)) {
	*storage
	.hashes
	.get(&(storage.best_number - (slots_in_an_epoch * U64::from(2))))?
	} else {
	storage.genesis_hash
	}
	}

but we can move the constant into a field and add a simple test for this:
manuyll mine a bunch of blocks, the request via Safe/Finalized tags

[yash-atreya]

@mattsse Thanks for the tag. I'll look into it.

[kamiyaa]

Kind of related, but the reason this was an issue for us is because
in solidity (running in anvil), blockHash of block 0 is 0x0
but getting the block through RPC provider returns the correct blockHash
and this causes a discrepancy in our tests specifically for block 0.
If this wasn't the case, we would be okay with finalized returning 0.

[mattsse]

ah I think I know what this is, will check