feat(plugin/evm): ACP-226 - set expected block gas cost to 0 in Granite (#1127)

Signed-off-by: Tsvetan Dimitrov <tsvetan.dimitrov23@gmail.com>
Co-authored-by: Tsvetan Dimitrov <tsvetan.dimitrov23@gmail.com>
Co-authored-by: Austin Larson <78000745+alarso16@users.noreply.github.com>
Co-authored-by: Stephen Buttolph <stephen@avalabs.org>

Author: 4 people

RELEASES.md

@@ -4,6 +4,7 @@
 
 - Removed deprecated flags `coreth-admin-api-enabled`, `coreth-admin-api-dir`, `tx-regossip-frequency`, `tx-lookup-limit`. Use `admin-api-enabled`, `admin-api-dir`, `regossip-frequency`, `transaction-history` instead.
 - Enabled RPC batch limits by default, and configurable with `batch-request-limit` and `batch-max-response-size`.
+- Implement ACP-226: Set expected block gas cost to 0 in Granite network upgrade, removing block gas cost requirements for block building.
 
 ## [v0.15.3](https://github.com/ava-labs/coreth/releases/tag/v0.15.3)
 

core/blockchain_ext_test.go

@@ -1425,7 +1425,7 @@ func GenerateChainInvalidBlockFeeTest(t *testing.T, create createFunc) {
 	// Ensure that key1 has some funds in the genesis block.
 	genesisBalance := new(big.Int).Mul(big.NewInt(1000000), big.NewInt(params.Ether))
 	gspec := &Genesis{
-		Config: params.TestChainConfig,
+		Config: params.TestFortunaChainConfig,
 		Alloc:  types.GenesisAlloc{addr1: {Balance: genesisBalance}},
 	}
 
@@ -1434,10 +1434,10 @@ func GenerateChainInvalidBlockFeeTest(t *testing.T, create createFunc) {
 	t.Cleanup(blockchain.Stop)
 
 	// This call generates a chain of 3 blocks.
-	signer := types.LatestSigner(params.TestChainConfig)
+	signer := types.LatestSigner(params.TestFortunaChainConfig)
 	_, _, _, err = GenerateChainWithGenesis(gspec, blockchain.engine, 3, ap4.TargetBlockRate-1, func(_ int, gen *BlockGen) {
 		tx := types.NewTx(&types.DynamicFeeTx{
-			ChainID:   params.TestChainConfig.ChainID,
+			ChainID:   params.TestFortunaChainConfig.ChainID,
 			Nonce:     gen.TxNonce(addr1),
 			To:        &addr2,
 			Gas:       ethparams.TxGas,
@@ -1466,7 +1466,7 @@ func InsertChainInvalidBlockFeeTest(t *testing.T, create createFunc) {
 	// Ensure that key1 has some funds in the genesis block.
 	genesisBalance := new(big.Int).Mul(big.NewInt(1000000), big.NewInt(params.Ether))
 	gspec := &Genesis{
-		Config: params.TestChainConfig,
+		Config: params.TestFortunaChainConfig,
 		Alloc:  types.GenesisAlloc{addr1: {Balance: genesisBalance}},
 	}
 
@@ -1475,11 +1475,11 @@ func InsertChainInvalidBlockFeeTest(t *testing.T, create createFunc) {
 	t.Cleanup(blockchain.Stop)
 
 	// This call generates a chain of 3 blocks.
-	signer := types.LatestSigner(params.TestChainConfig)
+	signer := types.LatestSigner(params.TestFortunaChainConfig)
 	eng := dummy.NewFakerWithMode(TestCallbacks, dummy.Mode{ModeSkipBlockFee: true, ModeSkipCoinbase: true})
 	_, chain, _, err := GenerateChainWithGenesis(gspec, eng, 3, ap4.TargetBlockRate-1, func(_ int, gen *BlockGen) {
 		tx := types.NewTx(&types.DynamicFeeTx{
-			ChainID:   params.TestChainConfig.ChainID,
+			ChainID:   params.TestFortunaChainConfig.ChainID,
 			Nonce:     gen.TxNonce(addr1),
 			To:        &addr2,
 			Gas:       ethparams.TxGas,

eth/gasprice/gasprice_test.go

@@ -381,13 +381,53 @@ func TestSuggestGasPricePreAP3(t *testing.T) {
 	require.NoError(t, err)
 }
 
+// NOTE: [Oracle.SuggestTipCap] does NOT simply return the "required" (minimum) tip.
+// The oracle computes a percentile of recent required tips (not observed on-chain tips)
+// within a time/blocks lookback window and applies a small floor (e.g., 1 wei in tests):
+//
+//	suggested = max(floor, recent-required-percentile)
+//
+// After Granite, BlockGasCost is 0 and per-block required tips are 0, so the oracle
+// suggestion equals the floor (1 wei) in steady state, regardless of high on-chain tips.
+// The cases below exercise behavior across forks using the same percentile logic and floor.
 func TestSuggestTipCapMaxBlocksLookback(t *testing.T) {
+	cases := []struct {
+		chainConfig *params.ChainConfig
+		expectedTip *big.Int
+	}{
+		// TODO: remove Fortuna case when we activate Granite
+		{
+			chainConfig: params.TestFortunaChainConfig,
+			expectedTip: big.NewInt(3),
+		},
+		{
+			chainConfig: params.TestChainConfig,
+			expectedTip: big.NewInt(1),
+		},
+	}
+	for _, c := range cases {
+		applyGasPriceTest(t, suggestTipCapTest{
+			chainConfig:     c.chainConfig,
+			numBlocks:       200,
+			extDataGasUsage: common.Big0,
+			genBlock:        testGenBlock(t, 550, 80),
+			expectedTip:     c.expectedTip,
+		}, defaultOracleConfig())
+	}
+}
+
+// Post-Granite, even very high observed tx tips should not affect SuggestTipCap, which
+// is computed from required tips. Since required tips are 0 in Granite, the returned
+// suggestion should be the floor (1 wei).
+func TestSuggestTipCapIgnoresObservedTipsPostGranite(t *testing.T) {
 	applyGasPriceTest(t, suggestTipCapTest{
-		chainConfig:     params.TestChainConfig,
-		numBlocks:       200,
+		chainConfig:     params.TestChainConfig, // Granite active in TestChainConfig
+		numBlocks:       20,
 		extDataGasUsage: common.Big0,
-		genBlock:        testGenBlock(t, 550, 80),
-		expectedTip:     big.NewInt(3),
+		// Generate blocks with very high on-chain tips to ensure they wouldn't bias the result
+		// if the oracle looked at observed tips. Expectation remains 1 wei.
+		genBlock:    testGenBlock(t, 100_000, 80),
+		expectedTip: big.NewInt(1),
 	}, defaultOracleConfig())
 }
 
@@ -402,14 +442,30 @@ func TestSuggestTipCapMaxBlocksSecondsLookback(t *testing.T) {
 }
 
 func TestSuggestTipCapIncludesExtraDataGas(t *testing.T) {
-	applyGasPriceTest(t, suggestTipCapTest{
-		chainConfig:     params.TestChainConfig,
-		numBlocks:       1000,
-		extDataGasUsage: big.NewInt(acp176.MinMaxPerSecond - int64(ethparams.TxGas)),
-		// The tip on the transaction is very large to pay the block gas cost.
-		genBlock: testGenBlock(t, 100_000, 1),
-		// The actual tip doesn't matter, we just want to ensure that the tip is
-		// non-zero when almost all the gas is coming from the extDataGasUsage.
-		expectedTip: big.NewInt(44_252),
-	}, defaultOracleConfig())
+	cases := []struct {
+		chainConfig *params.ChainConfig
+		expectedTip *big.Int
+	}{
+		// TODO: remove Fortuna case when we activate Granite
+		{
+			chainConfig: params.TestFortunaChainConfig,
+			expectedTip: big.NewInt(44_252),
+		},
+		{
+			chainConfig: params.TestChainConfig,
+			expectedTip: big.NewInt(1),
+		},
+	}
+	for _, c := range cases {
+		applyGasPriceTest(t, suggestTipCapTest{
+			chainConfig:     c.chainConfig,
+			numBlocks:       1000,
+			extDataGasUsage: big.NewInt(acp176.MinMaxPerSecond - int64(ethparams.TxGas)),
+			// The tip on the transaction is very large to pay the block gas cost.
+			genBlock: testGenBlock(t, 100_000, 1),
+			// The actual tip doesn't matter, we just want to ensure that the tip is
+			// non-zero when almost all the gas is coming from the extDataGasUsage.
+			expectedTip: c.expectedTip,
+		}, defaultOracleConfig())
+	}
 }

plugin/evm/customheader/block_gas_cost.go

@@ -32,6 +32,7 @@ var (
 // BlockGasCost calculates the required block gas cost based on the parent
 // header and the timestamp of the new block.
 // Prior to AP4, the returned block gas cost will be nil.
+// In Granite, the returned block gas cost will be 0.
 func BlockGasCost(
 	config *extras.ChainConfig,
 	parent *types.Header,
@@ -40,6 +41,9 @@ func BlockGasCost(
 	if !config.IsApricotPhase4(timestamp) {
 		return nil
 	}
+	if config.IsGranite(timestamp) {
+		return big.NewInt(0)
+	}
 	step := uint64(ap4.BlockGasCostStep)
 	if config.IsApricotPhase5(timestamp) {
 		step = ap5.BlockGasCostStep

plugin/evm/customheader/block_gas_cost_test.go

@@ -61,6 +61,14 @@ func TestBlockGasCost(t *testing.T) {
 			timestamp:  9,
 			expected:   big.NewInt(ap4.MinBlockGasCost + ap4.BlockGasCostStep*ap4.TargetBlockRate),
 		},
+		{
+			name:       "granite_returns_zero",
+			upgrades:   extras.TestGraniteChainConfig.NetworkUpgrades,
+			parentTime: 10,
+			parentCost: big.NewInt(ap4.MaxBlockGasCost),
+			timestamp:  10 + ap4.TargetBlockRate + 1,
+			expected:   big.NewInt(0),
+		},
 	}
 
 	for _, test := range tests {