Tracking issue: IBC Implementation

[avahowell]

This is a tracking issue for the high-level items required to reach our MVP3: integration of the IBC protocol for bridging assets in and out of Penumbra.

Prerequisites for mplementing the IBC protocol on Penumbra

• ICS-23 proof specification for our state tree (JMT). Our counterparties need this, we can use existing IAVL proof spec to verify our counterparty's proofs. - feat: Add prehash_compare_key to allow proving nonexistence in sparse trees cosmos/ics23#136
• ICS23 support jmt#18
• Light client implementation for Penumbra, also light clients that can verify Cosmos SDK chains. We should get this automatically: our counterparties can run Tendermint light clients of Penumbra, and we can use tendermint light clients (such as tendermint-rs) to track our counterparties state.
• Add IBC Packets to Penumbra transactions #464: A way to include IBC packets in Penumbra transactions, so that relayers can add messages to the chain.
• Tracking issue: MVP IBC Relayer infrastructure #465: A way for relayers to actually create those transactions.

Implementing the core IBC protocol in Penumbra's state machine

• Basic IBC chain parameters #466
• Implementation of IBC Light Client tracking logic #506
  • ibc: implement upgradeclient to allow counterparty chains to upgrade #635
  • Implement IBC Light Client Misbehavior Handling #636
• ICS-003 connection handshake for basic IBC connections support #637
• IBC channels support using ICS-004 #638
• IBC packets support using ICS-004 #639

After implementing the core IBC protocol (connections, channels, and packets), we can then

• ibc: replace duplicated state_keys with IBC paths from ibc-types #2859
• ICS-20 Fungible Token Transfer Support #467
  • Implement ICS20 balance-of-payments or other circuit-breaker functionality. #981
  • Test IBC relaying between Penumbra and any Cosmos testnet #2284
  • ibc: add support for host chain upgrades #2985
• Implement client-side support for ICS20 withdrawals - add support for ICS20 withdrawals to pcli #2301
• ibc: check for tendermint client update problems #3193
• IBC-related governance proposals #2173

Testing integrations, developer experience improvements

• ibc: go-relayer doesn't work on Penumbra v0.62.0 #3222
• ibc: check for tendermint client update problems #3193
• Exercise ICS20 timeouts end-to-end against a Cosmos-SDK chain. #3116
• ibc: rename ibc_actions proto field for legibiility #3209
• Counterparty chains don't have ICS23 0.10.0 support. #3045
• Interchaintest should have Penumbra support (via pclientd) strangelove-ventures/interchaintest#644
• Penumbra should have tests for {clients, conns, chans, transfer}. strangelove-ventures/interchaintest#313
• End-to-end ICS-20 test in CI #1813
• Register chain in cosmos registry, osmosis chain registry, etc. #2914
• Tracking Issue: support IBC integration in Astria #3125

Stretch goals, non-blocking for mainnet, but tracking because completing these would make us friendly FOSS maintainers:

• Commit the JMT proof spec to cosmos/ics23 repo
• Add test vectors to cosmos/ics23 repo

Many IBC primitives (such as the protos for connections, channels, packets, etc) are already implemented in ibc-rs.

[conorsch]

This tracking issue has been around for nearly 2y now, and although it's been updated frequently, we need a fresh look at the state of play for IBC. Let's close it. @avahowell and I will work to respecify with work in light of recent experiences.

[hdevalence]

Closing as requested.