fix(pyth): automate router set rotation via vaa

[chalabi2]

Summary

• automate pyth_vaa router-set rotation through the existing submit_v_a_a path
• accept signed router-set upgrade VAAs from Hermes instead of requiring a manual config update
• store router sets by index and advance the active set when the submitted rotation VAA is valid
• preserve the get_config response shape that pyth_pro and Hermes use at runtime

Validation

• cargo fmt -p pyth_vaa -- --check
• cargo test -p pyth_vaa
• cargo clippy -p pyth_vaa --all-targets -- -D warnings
• local Akash chain + Hermes one-shot update
• Dockerized Hermes one-shot update after local router-set rotation

Local validation reproduced the stale-router failure, submitted the router-set
rotation through submit_v_a_a, then confirmed Hermes price updates succeeded
against pyth_pro and x/oracle after the rotation.

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📥 Commits

Reviewing files that changed from the base of the PR and between 096bff5 and 223416a.

📒 Files selected for processing (5)

• contracts/pyth_vaa/src/contract.rs
• contracts/pyth_vaa/src/error.rs
• contracts/pyth_vaa/src/msg.rs
• contracts/pyth_vaa/src/router.rs
• contracts/pyth_vaa/src/state.rs

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Walkthrough

The contract now stores router sets by index and rotates them through signed governance VAAs. It adds governance-chain validation, migration from the legacy configuration, indexed router-set parsing, new errors, query fields, and tests for rotation and rejection paths.

Changes

Router rotation and migration

Layer / File(s)	Summary
State and message contracts contracts/pyth_vaa/src/state.rs, contracts/pyth_vaa/src/msg.rs, contracts/pyth_vaa/src/error.rs	Configuration now stores governance and emitter settings. Router state and indexed router sets use separate storage. Messages support governance-chain configuration, migration, and SubmitVAA. New errors cover invalid governance updates and router-set transitions.
Governance router-set parsing contracts/pyth_vaa/src/router.rs	Governance packets now validate the module, action, target chain, router-set index, router count, address length, and duplicate addresses.
VAA rotation and migration flow contracts/pyth_vaa/src/contract.rs	Instantiation and migration populate indexed router state. SubmitVAA verifies governance packets, requires the next index, stores the new router set, and updates the active index. Queries and verification load the active router set. Tests cover rotation, rejection paths, replay, and migration.

Estimated code review effort: 4 (Complex) | ~45 minutes

Merge Risk: ⚪ Minimal · up to 22341

Router-set rotation now requires current-router signatures, validates governance targets, and advances sequentially while preserving the existing configuration response shape. No current merge-blocking risk is identified.

Suggested reviewers: boz, chainzero, cloud-j-luna

Poem

A rabbit checks the router trail
Signed packets guide the changing sail
Old state hops to storage new
Indexes rise from one to two
Safe paths bloom in governance light

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 33.33% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 39 functions across 5 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Title check	✅ Passed	The title clearly and concisely describes the main change: automated router-set rotation through VAA submission.
Description check	✅ Passed	The description directly explains the router-set rotation changes and documents relevant validation, including tests and local Hermes/Akash scenarios.

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• Create stacked PR
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• Create PR with unit tests
• Commit unit tests in branch chalabi/pyth-router-set-rotation-fix

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