Feat/v15 packet forward middleware

[TheAlchemist616]

Summary

Integrates Packet Forward Middleware (PFM, v10.6.0) into the IBC transfer stack as the v15 upgrade, giving Terra Classic multi-hop IBC routing: a single MsgTransfer can route atomically through Terra Classic to a third chain (chain-A → Terra Classic → chain-B), with automatic refund/timeout handling.

Motivation

Today Terra Classic can only move assets across channels it holds directly — reaching a chain it has no direct channel with takes multiple manual transactions, or isn't possible in a single flow. PFM is the standard multi-hop component run by Osmosis, Stride, Injective, Sei and most major Cosmos chains. Adding it:

• lets LUNC and other assets reach the whole IBC network in one hop (e.g. via Osmosis / the Hub) without opening a channel to every counterparty;
• ensures assets bridged onto Terra Classic aren't stranded — they can flow onward across IBC;
• composes with the existing ibc-hooks module (a routed packet can also trigger a CosmWasm contract);
• supports an optional fee_percentage that skims forwarded packets to the community pool (shipped at 0 here; governance can raise it later via MsgUpdateParams).

Changes

• New module packetfowardmiddleware (name is the upstream spelling, frozen for state compat): one KV store, one module account (intermediate receiver for in-flight forwarded packets), one params subspace. Registered in ModuleBasics, the module manager, and the begin/end/init-genesis orderings.
• Transfer stack re-composed to channel → ibc-hooks → packet-forward → transfer (the Osmosis ordering), in app/keepers/routers.go.
• v15 upgrade handler (app/upgrades/v15/): adds the PFM store via StoreUpgrades.Added; RunMigrations initializes the module's default genesis (fee_percentage = 0). No bespoke state migration.

Dependency changes (please review)

Module	Before	After
cosmos/ibc-apps/middleware/packet-forward-middleware/v10	—	v10.6.0 (new)
cosmos/ibc-go/v10	v10.5.0	v10.6.0 (transitive minor bump pulled by PFM)

Flagging the ibc-go bump explicitly so it's clear this PR is not only PFM — it's a minor patch release pulled in transitively, and it compiles + tests clean.

Testing

• go build ./... — clean.
• terrad init — module registers and appears in default genesis.
• tests/interchaintest/ibc_pfm_terra_hop_test.go::TestTerraAsPFMHop — a new live 3-chain test (gaia → Terra (this build) → osmosis) with a relayer. It asserts that Terra itself emits the onward send_packet after receiving from gaia, and that osmosis credits the forwarded funds. Passes end-to-end (ok … 202s).

This closes a real coverage gap: the existing PFM tests (TestTerraPFM, TestTerraGaiaOsmoPFM) only exercise Osmosis as the forwarding hop, with Terra as source/destination — they never test Terra Classic doing the forwarding.

Risk

Low. Consensus-breaking only in that it adds a module store, so it must be applied at a governance-set height via the standard Cosmovisor / coordinated-swap drill. No parameter changes to any existing module. PFM is battle-tested across the Cosmos ecosystem, and non-forwarded IBC transfers are unaffected.

Notes for reviewers

• app/upgrades/v15/README.md documents the change; app/upgrades/v15/PROPOSAL.md contains the governance MsgSoftwareUpgrade runbook.
• The PFM keeper's ics4Wrapper is wired to IBCKeeper.ChannelKeeper; the ibc-hooks + PFM stack ordering matches the Osmosis reference and is confirmed working by TestTerraAsPFMHop.

Checklist

• Builds (go build ./...)
• New interchaintest passes (TestTerraAsPFMHop)
• Upgrade handler + store registration added (v15)
• No changes to existing module params
• Reviewed by L1JTF / maintainers

[TheAlchemist616]

Apologies, pull request made by mistake

…

On Mon, Jun 1, 2026, 5:51 AM StrathCole ***@***.***> wrote: ***@***.**** commented on this pull request. ------------------------------ On app/upgrades/v15/PROPOSAL.md <#665 (comment)>: Readme/proposal data for upgrades don't belong in the main repo. There is a specific repo for docs. https://github.com/classic-terra/documents/ — Reply to this email directly, view it on GitHub <#665?email_source=notifications&email_token=BWMNGROCGECA3RZSSIOSAWD45VG3NA5CNFSNUABKM5UWIORPF5TWS5BNNB2WEL2QOVWGYUTFOF2WK43UKJSXM2LFO4XTINBQGAYTKNJYGQ42M4TFMFZW63VGMF2XI2DPOKSWK5TFNZ2KYZTPN52GK4S7MNWGSY3L#pullrequestreview-4400155849>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/BWMNGRLUJP5UTIEKRVKORAT45VG3NAVCNFSM6AAAAACZVJAHBOVHI2DSMVQWIX3LMV43YUDVNRWFEZLROVSXG5CSMV3GSZLXHM2DIMBQGE2TKOBUHE> . Triage notifications, keep track of coding agent tasks and review pull requests on the go with GitHub Mobile for iOS <https://github.com/notifications/mobile/ios/BWMNGRIJZCUJMIRQRRI25LT45VG3NA5CNFSNUABKM5UWIORPF5TWS5BNNB2WEL2QOVWGYUTFOF2WK43UKJSXM2LFO4XTINBQGAYTKNJYGQ42M4TFMFZW63VGMF2XI2DPOKSWK5TFNZ2KUZTPN52GK4S7NFXXG> and Android <https://github.com/notifications/mobile/android/BWMNGROMNM73RIU5MLCHE6T45VG3NA5CNFSNUABKM5UWIORPF5TWS5BNNB2WEL2QOVWGYUTFOF2WK43UKJSXM2LFO4XTINBQGAYTKNJYGQ42M4TFMFZW63VGMF2XI2DPOKSWK5TFNZ2K4ZTPN52GK4S7MFXGI4TPNFSA>. Download it today! You are receiving this because you authored the thread.Message ID: ***@***.***>

[StrathCole]

Apologies, pull request made by mistake
…

Shall I close it?

[TheAlchemist616]

Done
Thank you
Will still use it for discussion on Discourse, will repush to appropriate locations if/when it passes/fails on the eventual governance vote down the road.