giga: report EIP-1559 effective gas price on receipt (CON-256)

[wen-coding]

GIGA's executeEVMTxWithGigaExecutor was passing ethTx.GasPrice() into the core.Message used to construct the receipt. For dynamic-fee (EIP-1559) txs Transaction.GasPrice() returns GasFeeCap, so the receipt wrongly reported maxFee for any tx that actually paid baseFee + tip < maxFee.

This breaks EIP-1559 RPC semantics for clients (ethers, hardhat-ethers, etc.) that read receipt.effectiveGasPrice to compute spend / display per-tx cost.

What's actually wrong

V2's x/evm/keeper/msg_server.go constructs the message via server.GetEVMMessage(ctx, tx, sender), which has the EIP-1559 adjustment built in:

baseFee := k.GetBaseFee(ctx)
if baseFee != nil {
    msg.GasPrice = msg.GasPrice.Add(msg.GasTipCap, baseFee)
    if msg.GasPrice.Cmp(msg.GasFeeCap) > 0 {
        msg.GasPrice = msg.GasFeeCap
    }
}

GIGA's path hand-rolls a core.Message literal in executeEVMTxWithGigaExecutor and missed this step.

The fix

Use the already-computed effectiveGasPrice (line 1866 of app/app.go, which already does min(baseFee + tipCap, feeCap) and is what the chain actually charges via stateDB.SubBalance at line 1871) when constructing the receipt's core.Message.

The chain's actual fee charge has always been correct — only the value reported on the receipt was wrong.

Things done

• Single-line code change in app/app.go executeEVMTxWithGigaExecutor: GasPrice: ethTx.GasPrice() → GasPrice: effectiveGasPrice
• Unit test in giga/deps/xevm/keeper/receipt_test.go documents the WriteReceipt contract: receipt.EffectiveGasPrice == msg.GasPrice (caller is responsible for passing the EIP-1559 effective price)
• gofmt -s clean

🤖 Generated with Claude Code

[github-actions]

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Build	Format	Lint	Breaking	Updated (UTC)
✅ passed	✅ passed	✅ passed	✅ passed	May 5, 2026, 2:32 PM

[codecov]

Codecov Report

❌ Patch coverage is 0% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 59.07%. Comparing base (52d368f) to head (ad55ad6).

Files with missing lines	Patch %	Lines
app/app.go	0.00%	1 Missing ⚠️

❌ Your patch check has failed because the patch coverage (0.00%) is below the target coverage (50.00%). You can increase the patch coverage or adjust the target coverage.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3384      +/-   ##
==========================================
- Coverage   59.08%   59.07%   -0.01%     
==========================================
  Files        2100     2099       -1     
  Lines      173008   172972      -36     
==========================================
- Hits       102219   102188      -31     
+ Misses      61926    61921       -5     
  Partials     8863     8863              

Flag	Coverage Δ
sei-chain-pr	52.46% <0.00%> (?)
sei-db	70.41% <ø> (ø)

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

Files with missing lines	Coverage Δ
app/app.go	69.78% <0.00%> (-0.07%)	⬇️

... and 28 files with indirect coverage changes

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[arajasek]

Thanks!

[seidroid]

Successfully created backport PR for release/v6.5:

• Backport release/v6.5: giga: report EIP-1559 effective gas price on receipt (CON-256) #3387

[arajasek]

/backport

[seidroid]

Successfully created backport PR for release/v6.4:

• Backport release/v6.4: giga: report EIP-1559 effective gas price on receipt (CON-256) #3390