fix(giga): fall back to v2 on execution errors

[philipsu522]

Describe your changes and provide context

This fixes a live RPC-level divergence, not only a defensive edge case. On main, the parity test reaches matching consensus fields but fails receipt parity: Giga stamps TxType=2 and gasUsed=gasLimit, while V2 writes an EndBlock synthetic receipt with zero values. Mixed Giga/V2 fleets can therefore return different receipts for the same transaction.

State-transition errors now route through the existing V2 fallback instead of duplicating V2's fee, nonce, receipt, deferred-info, and ABCI result handling. This adds an execution_failed abort sentinel and fallback metric reason. Because the Giga StateDB has not been finalized when ExecuteTransactionFeeCharged returns an error, its transaction-local cache is discarded before V2 re-runs the transaction. Both sequential and OCC Giga paths use the existing fallback plumbing.

The EIP-7623 floor-data-gas parity test covers deterministic ABCI fields, LastResultsHash, nonce, receipt, sender balance, fee-collector balance, and per-transaction coinbase balance in sequential and OCC modes.

Operational tradeoff: this creates the first deterministic single-transaction trigger that passes CheckTx at roughly 27.5k gas but reverts an entire OCC batch to V2. Operators should alert on app_giga_fallback_to_v2{reason="execution_failed"}; per-transaction OCC fallback should be tracked as follow-up work.

Testing performed to validate your change

• go test ./giga/tests -run '^TestGiga_FailedExecutionFallsBackToV2$' -count=1
• go test ./giga/tests -count=1
• go test ./app -run 'TestGiga|TestOCC|TestProcess' -count=1
• gofmt -s and goimports on all changed Go files

Slack Thread

  

[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	Jul 16, 2026, 3:15 PM

[codecov]

Codecov Report

❌ Patch coverage is 71.42857% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 59.02%. Comparing base (703e48d) to head (6ab6c68).

Files with missing lines	Patch %	Lines
giga/executor/utils/errors.go	50.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3768      +/-   ##
==========================================
- Coverage   59.92%   59.02%   -0.91%     
==========================================
  Files        2288     2201      -87     
  Lines      190180   180310    -9870     
==========================================
- Hits       113971   106419    -7552     
+ Misses      66049    64534    -1515     
+ Partials    10160     9357     -803     

Flag	Coverage Δ
sei-chain-pr	59.93% <71.42%> (?)
sei-db	70.41% <ø> (-0.22%)	⬇️
sei-db-state-db	?

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

Files with missing lines	Coverage Δ
app/app.go	71.52% <100.00%> (+0.35%)	⬆️
giga/executor/utils/errors.go	50.00% <50.00%> (ø)

... and 88 files with indirect coverage changes

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[bdchatham]

This is a live bugfix, not just defense: the new test fails on main at receipt parity (giga stamps TxType=2, gasUsed=gasLimit; v2 writes the EndBlock synthetic receipt with zeros) while consensus fields match. State the red-proof in the description so the severity (RPC-level receipt divergence on mixed fleets) is on record.

[bdchatham]

Live mixed-fleet validation on harbor

Validated this PR end-to-end on an ephemeral harbor chain: 4 validators + one v2 RPC node (giga_executor.enabled=false, occ_enabled=false) on nightly-20260715-65411b1 (= #3753 merge, pre-this-PR), plus one giga+OCC RPC node swapped between the pre-fix image and sei/sei-chain:pr3768-6ab6c68 (built from head 6ab6c68 via ecr.yml workflow_dispatch).

Probe: EIP-7623 floor-data-gas tx (1000 zero calldata bytes, gasLimit 27500 — clears the ante's intrinsic check, fails inside geth's Execute()), exercised via qa-testing's tests/chain_tests/floorDataGas.spec.ts (sei-protocol/qa-testing#143/#145).

Pre-fix giga node — divergence reproduced. Same tx hash, eth_getTransactionReceipt on both nodes:

field	giga (pre-fix)	v2
gasUsed	0x6b6c (gas limit)	0x0
cumulativeGasUsed	0x6b6c	0x0
effectiveGasPrice	0x165a0bc00	0x0
status / type	0x0 / 0x2	0x0 / 0x2

Consensus held throughout (nonce, sender balance, and fee charge matched v2 on both executors) — receipt-only divergence, invisible to the AppHash/LastResultsHash gate, per the RCA.

This PR's image — fixed. Giga node on pr3768-6ab6c68, peered against unfixed validators and the unfixed v2 node:

• qa-testing floor-data-gas spec: 4/4 passing (was 3/4, failing on exactly gasUsed 27500 vs 0)
• Fresh same-tx cross-node diff: receipts byte-identical — {status: 0x0, gasUsed: 0x0, cumulativeGasUsed: 0x0, type: 0x2, effectiveGasPrice: 0x0}
• Fallback observable on the node's metrics: sei_chain_app_giga_fallback_to_v2_total{reason="execution_failed", scope="batch"} 2 — one per probe tx, scope="batch" as expected under OCC
• Node synced ~4,300 blocks produced under the old image and stayed in consensus with the unfixed fleet

The qa-testing spec now guards this class continuously: it locks the canonical v2 receipt shape at the RPC surface, so a regression on any executor fails it regardless of which node serves the query.