ETH will require a bespoke precompile for post-bridging minting

[PaulRBerg]

As pointed out here, ETH will be the only asset on the chain that will not be associated with a smart contract (which minted it using the MINT opcode).

This means that ETH will only be obtainable via bridges, and bridging systems will require a mechanism to mint ETH. A precompile sounds like the best way to implement this (similar to #86).

P.S. it might be worth investigating how other rollups such as Optimism and Arbitrum deal with this issue. They must have an equivalent system-level functionality for minting ETH out of thin air.

CC @sablier-labs/sabvm

[PaulRBerg]

Potentially relevant:

Optimism's Mint Manager Owner.

[IaroslavMazur]

The ETH Base Token would, indeed, have to be created differently from the other NTs. One reason for this is that its token_id is hardcoded to 0, while the token_ids of the other NTs are computed dynamically (based on the minter's address and the passed sub_id).

Or have you thought of some other reasons when you suggested the above?

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ETH will only be obtainable via bridges

Bridges, plural?

Given that ETH will be the Base Token that the network depends on, I think that it'd be fair for us to be the only ones with the ability to mint it.

Here's how the plan could look like:

• Create a custom (different from the rest of the NTs) way to mint the ETH NT;
  • This could be a separate mint() function in one of our precompiles, callable only by a Sablier admin address.
• On top of the above, create the official bridging application which would:
  • accept ETH deposits (which would be locked) on Ethereum Mainnet and other L2s - and mint the equivalent amount of sabETH;
  • accept sabETH withdrawals, burning it on SabVM - and giving (back) the ETH locked at the "source" chains.

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Side note: we'll need to disable the ETH emission/burning during the block creation for Mainnet.

I've just realized this and don't yet know how other L2s approach this, but looking at the latest Optimism txs (e.g. this one), I understand that they're doing exactly what I suggested above. Optimism, like our Mainnet, has ETH - and not their OP token - as the Base Token.

If you agree, I'll create a task for this.

[PaulRBerg]

Since we decided to sunset the rollup, there's no need to respond here, but I will do it anyway for the sake of completeness and intellectual curiosity.

I generally agree with your conclusions. Just a few comments:

One reason for this is that its token_id is hardcoded to 0
...
Or have you thought of some other reasons when you suggested the above?

No. You said the same thing as I did in the OP but using different, more low-level technical terms.

Bridges, plural?

Good point. There should be only one official way to mint ETH, at least at the beginning, for simplicity purposes.

we'll need to disable the ETH emission/burning during the block creation for Mainnet

Correct.

[PaulRBerg]

I started a Q&A on StackExchange about whether rollups burn ETH in the style of EIP-1559:

Do optimistic rollups burn ETH?