NetworkUpgrade::NU5 and network protocol version

[teor2345]

Is your feature request related to a problem? Please describe.

We want to add a NetworkUpgrade::NU5 network upgrade variant, and a network protocol version for NU5.

As part of this change, we need to write a draft NU5 ZIP.

Describe the solution you'd like

• write a draft NU5 ZIP
  • we don't need to have a list of included ZIPs, just the branch id / numbers / etc.
  • [ZIP 252] Network Upgrade 5 zcash/zips#446
• add a NetworkUpgrade::NU5 network upgrade variant
  • activation block heights will be None until the NU5 ZIPs are decided and the target dates are set

  • zebra/zebra-chain/src/parameters/network_upgrade.rs

    Line 16 in 128643d

    pub enum NetworkUpgrade {

• add the NU5 consensus branch ID

  • zebra/zebra-chain/src/parameters/network_upgrade.rs

    Line 89 in 128643d

    pub(crate) const CONSENSUS_BRANCH_IDS: &[(NetworkUpgrade, ConsensusBranchId)] = &[

• add a network protocol version for NU5

  • zebra/zebra-network/src/protocol/external/types.rs

    Line 46 in 128643d

    pub fn min_for_upgrade(network: Network, network_upgrade: NetworkUpgrade) -> Self {

For future reference, we also made this change:

• add NU5 to the protocol::version_consistent test

  • zebra/zebra-network/src/protocol/external/types.rs

    Line 190 in 128643d

    assert!(highest_network_upgrade == Canopy || highest_network_upgrade == Heartwood,

Describe alternatives you've considered

These changes are required for NU5.

Additional context

NU4 ZIP: https://zips.z.cash/zip-0251
NU5 ZIP: zcash/zips#446

[teor2345]

We've talked to the zcashd team, and they're happy for us to write the draft NU5 ZIP.

[teor2345]

We've talked to the zcashd team, and they're happy for us to write the draft NU5 ZIP.

The draft ZIP is at zcash/zips#446 , it has passed initial review.

[oxarbitrage]

It looks like NetworkUpgrade::NU5 should be NetworkUpgrade::Orchard ?

[str4d]

No. Orchard is the name of the proposed new shielded pool, not the name of the upgrade (which as proposed includes things other than Orchard). We made this mistake for Sapling (naming the upgrade after the pool), and it has caused non-trivial confusion.

[oxarbitrage]

So, to be extra clear. The name of the upgrade will be NU5 even if previous ones had names like Sapling, Blossom, etc. Is that correct or NU5 will actually have a name(different than Orchard)?

[oxarbitrage]

Forget #1797 (comment), the code name is actually NU5 according to the draft zip: https://github.com/teor2345/zips/blob/zip-252-nu5/zip-0252.rst#terminology

Thanmk you @str4d

[teor2345]

So, to be extra clear. The name of the upgrade will be NU5 even if previous ones had names like Sapling, Blossom, etc. Is that correct or NU5 will actually have a name(different than Orchard)?

The code-name for the sixth Zcash network upgrade has not been chosen yet.

I've updated the draft ZIP to reflect that:
https://github.com/zcash/zips/pull/446/files#r584385297

There are three possible outcomes for Zebra:

• There is no code name chosen, and the enum keeps getting called NU5
• The community chooses a code name, the enum keeps getting called NU5, and everything works
• The community chooses a code name, we use fastmod or a similar tool to easily change NU5 to that name

(We don't need to make that decision now.)