Port sei-v3 PR #510: crash-safe consensus state persistence

[wen-coding]

Summary

This is a port of sei-protocol/sei-v3#510 to sei-chain.

Adds crash-safe A/B file persistence for the autobahn consensus inner state (votes and QCs). This prevents double-voting on restart (a slashable offense) and enables fast view synchronization after cluster-wide outages by persisting QC justifications.

Key changes

• Crash-safe A/B file persistence (persist.go): Alternates writes between two files (_a.pb/_b.pb) with sequence numbering. On load, picks the file with the higher seq; tolerates one corrupt file (crash mid-write recovery). Only needs one fsync per write (no directory sync after initial setup).
• Persisted consensus state (persisted_inner.go): Defines the persistedInner struct holding CommitQC, PrepareQC, TimeoutQC, and current-view votes. Includes validation logic that checks internal consistency and cryptographic signatures on load.
• Inner refactor (inner.go): inner now embeds persistedInner so persisted fields are promoted. Added newInner constructor that loads and validates persisted state.
• State integration (state.go): NewState now returns (*State, error). Added PersistentStateDir config option. Persistence is called in runOutputs before broadcasting votes.
• Protobuf (autobahn.proto, autobahn.pb.go): Added PersistedInner and PersistedWrapper message definitions. Regenerated via buf generate.
• Test helper (types/testonly.go): Added GenProposalAt for generating proposals at a specific view.
• Caller updates (giga/avail_test.go, giga/data_test.go): Adapted for NewState returning an error.

Adaptation notes (sei-v3 → sei-chain)

• Import paths: sei-stream/stream/consensus → sei-tendermint/internal/autobahn/consensus
• Package name: protocol → pb (protobuf package)
• Concurrency model: utils.AtomicWatch[inner].Update() → utils.Mutex[*utils.AtomicSend[inner]].Lock()/Store()
• Random type: *rand.Rand → utils.Rng in test helpers
• Protobuf test: innerProtoConv.Test() replaced with manual roundtrip using google.golang.org/protobuf/proto (gogo/protobuf incompatibility with protoc-gen-go generated types)

New files (5)

• sei-tendermint/internal/autobahn/consensus/persisted_inner.go
• sei-tendermint/internal/autobahn/consensus/persist.go
• sei-tendermint/internal/autobahn/consensus/inner_test.go
• sei-tendermint/internal/autobahn/consensus/persist_test.go
• sei-tendermint/internal/autobahn/consensus/persisted_inner_test.go

Modified files (7)

• sei-tendermint/internal/autobahn/autobahn.proto
• sei-tendermint/internal/autobahn/pb/autobahn.pb.go
• sei-tendermint/internal/autobahn/consensus/inner.go
• sei-tendermint/internal/autobahn/consensus/state.go
• sei-tendermint/internal/autobahn/types/testonly.go
• sei-tendermint/internal/p2p/giga/avail_test.go
• sei-tendermint/internal/p2p/giga/data_test.go

Test plan

• All autobahn package tests pass (go test ./sei-tendermint/internal/autobahn/...)
• All giga package tests pass (go test ./sei-tendermint/internal/p2p/giga/...)
• gofmt -s clean on all modified files
• Protobuf regenerated via buf generate (matching protoc-gen-go v1.36.10, protoc (unknown))
• Full content comparison against sei-v3 source confirms no lost comments or code

Made with Cursor

[github-actions]

The latest Buf updates on your PR. Results from workflow Buf / buf (pull_request).

Build	Format	Lint	Breaking	Updated (UTC)
✅ passed	✅ passed	✅ passed	✅ passed	Feb 13, 2026, 11:45 PM

[codecov]

Codecov Report

❌ Patch coverage is 77.09924% with 60 lines in your changes missing coverage. Please review.
✅ Project coverage is 57.21%. Comparing base (7407960) to head (7f986d9).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
...-tendermint/internal/autobahn/consensus/persist.go	76.36%	16 Missing and 10 partials ⚠️
...int/internal/autobahn/consensus/persisted_inner.go	83.72%	7 Missing and 7 partials ⚠️
...ei-tendermint/internal/autobahn/consensus/inner.go	68.75%	2 Missing and 8 partials ⚠️
...ei-tendermint/internal/autobahn/consensus/state.go	68.75%	7 Missing and 3 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2893      +/-   ##
==========================================
+ Coverage   57.15%   57.21%   +0.06%     
==========================================
  Files        2091     2093       +2     
  Lines      171524   171755     +231     
==========================================
+ Hits        98033    98271     +238     
+ Misses      64751    64727      -24     
- Partials     8740     8757      +17     

Flag	Coverage Δ
sei-chain	52.69% <77.09%> (+0.07%)	⬆️
sei-cosmos	48.16% <ø> (+<0.01%)	⬆️
sei-db	68.72% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
sei-tendermint/internal/autobahn/types/testonly.go	94.44% <100.00%> (+0.08%)	⬆️
...ei-tendermint/internal/autobahn/consensus/inner.go	62.22% <68.75%> (+0.68%)	⬆️
...ei-tendermint/internal/autobahn/consensus/state.go	82.92% <68.75%> (-4.49%)	⬇️
...int/internal/autobahn/consensus/persisted_inner.go	83.72% <83.72%> (ø)
...-tendermint/internal/autobahn/consensus/persist.go	76.36% <76.36%> (ø)

... and 36 files with indirect coverage changes

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