Will getBlockNumber() default to return safe head post merge?

[NIC619]

Post merge, are getBlockNumber() related calls to endpoint use the old default latest tag or the new available safe tag?
There seem to be a little difference between them:

Post-merge, execution layer APIs (e.g. JSON RPC) will expose the safe head using a safe tag. Under normal network conditions the safe head and the actual tip of the chain will be equivalent (with safe head trailing only by a few seconds). Safe heads will be less likely to be reorged than the current proof of work latest blocks.

Ref: impacts post merge

[ricmoo]

Thanks for the heads up! I will research and experiment with what makes the most sense. This will likely require a minor bump. I’ll also use v6 as a chance to incorporate whatever makes the most sense. :)

[daithi-coombes]

Getting the latest block may be practically not possible with just jsonrprc post merge.

From my local tests on kiln using geth@latest & prysm@latest the execution layer will show synced and that it has the latest block even though the consensus layer is still syncing. There is about 6000 slots on consensus layer still to sync when blockNumber == highestBlock, meaning finalized and safe will give a false positive.

Am testing erigon execution layer today, will update as it may be a geth issue only. Also post-merge fork may fix this but don't see anything anywhere

[briannnyee]

Hi. Is there any update on the question?

[ricmoo]

The getBlockNumber still uses latest, but the getBlock now supports safe and finalized tags, so you can use getBlock("safe").number on networks that are post-merge compliant.

In v6, the safe and finalized tags will also be added for events, so you can use provider.on("finalized", …). :)

[cohuebn]

@ricmoo : I just wanted to check if there are still plans to support the safe tag for events? I tried on v6.2.0 and received an error when subscribing to the safe tag. I wasn't sure if this was misuse on my part or if the safe tag event is just not supported yet?

Details

This code block currently fails:

latestSafeChangedProvider.on("safe", (blockNumber: number) => {
  logger.debug({ blockNumber }, "Received new safe block number");
});

In the above block, latestSafeChangedProvider is a JsonRpcProvider. This is the error received:
TypeError: unknown ProviderEvent (argument="event", value="safe", code=INVALID_ARGUMENT, version=6.2.0)

[ricmoo]

There are still plans, but it has not been added yet. If you want to create a feature request issue for it, that will help remind me. :)

[cohuebn]

Great, thanks @ricmoo ! I added feature request #3921 to track this.