BurnBaseFee in ApplyTransaction after RefundGas

[AryaLanjewar3005]

Description

Base Fee Burn

Previously, the baseFee was collected in the ante-handler and later distributed by the Cosmos SDK distribution module.

This PR changes that behavior to burn the base fee, aligning the mechanism more closely with Ethereum’s EIP-1559 model.

New Logic

After a transaction is executed:

1. During refundGas, the sender is refunded:
   • baseFee * gasUsed
   • Any leftover gas amount
2. Once the refund is completed, the protocol burns baseFee * gasUsed from the sender’s account.

This effectively removes the base fee from circulation instead of redistributing it.

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Fixes

Issue 1: TxEthereum Test Failure

Problem:
The TxEthereum test case was failing because the feeCollector had zero funds.
This happened because the test bypassed the ante-handler, where fees are normally collected.

Solution:
Funded the feeCollector account before executing TxEthereum in the test setup.

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Issue 2: Bank Extension Integration Test Failures

Problem:
After introducing the burnBaseFee feature, integration tests started failing.

Previously:

• Transaction fees remained in the system.
• Fees were distributed to validators or the fee collector.

With the new logic:

• Transaction fees are burned.
• Total supply decreases after each transaction (similar to Ethereum EIP-1559).

Failure Scenario

During test setup:

1. Network initializes with a fixed total supply.
2. BeforeEach deploys a contract, consuming gas (~0.337 tokens).
3. Fees are burned, reducing total supply.
4. Tests expected hardcoded supply values, causing failures.

Solution

Updated tests to query the total supply dynamically instead of using hardcoded values.

// Before: Hardcoded values
cosmosEVMTotalSupply, _ = new(big.Int).SetString("200003000000000000000000", 10)
xmplTotalSupply, _      = new(big.Int).SetString("200000000000000000000000", 10)

// After: Dynamic query
totSupplRes, err := is.grpcHandler.GetTotalSupply()
cosmosEVMTotalSupply = totSupplRes.Supply.AmountOf(is.bondDenom).BigInt()
xmplTotalSupply = totSupplRes.Supply.AmountOf(is.tokenDenom).BigInt()

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Author Checklist

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I have...

• tackled an existing issue or discussed with a team member
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• targeted the main branch

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