Replace eip1559BaseFeeFixedValue* spec options with eip1559BaseFeeMinValue and eip1559BaseFeeMinValueTransition

CHANGELOG.md

@@ -1,8 +1,8 @@
 ## OpenEthereum v3.3.0-rc.14
 
 Enhancements:
-* Add eip1559BaseFeeFixedValue and eip1559BaseFeeFixedValueTransition spec options
+* Add eip1559BaseFeeMinValue and eip1559BaseFeeMinValueTransition spec options
-* Activate eip1559BaseFeeFixedValue on xDai at London hardfork block (19040000)
+* Activate eip1559BaseFeeMinValue on xDai at London hardfork block (19040000)
 * Delay difficulty bomb to June 2022 (EIP-4345)
 
 ## OpenEthereum v3.3.0-rc.13

crates/ethcore/res/chainspec/xdai.json

@@ -60,9 +60,11 @@
 		"eip3529Transition": 19040000,
 		"eip3541Transition": 19040000,
 		"eip1559Transition": 19040000,
+		"eip1559BaseFeeMaxChangeDenominator": "0x8",
 		"eip1559ElasticityMultiplier": "0x2",
-		"eip1559BaseFeeFixedValue": "0x4A817C800",
+		"eip1559BaseFeeInitialValue": "0x3b9aca00",
-		"eip1559BaseFeeFixedValueTransition": 19040000,
+		"eip1559BaseFeeMinValue": "0x4A817C800",
+		"eip1559BaseFeeMinValueTransition": 19040000,
 		"eip1559FeeCollector": "0x6BBe78ee9e474842Dbd4AB4987b3CeFE88426A92",
 		"eip1559FeeCollectorTransition": 19040000,
 		"registrar": "0x6B53721D4f2Fb9514B85f5C49b197D857e36Cf03",

crates/ethcore/src/machine/impls.rs

@@ -467,8 +467,8 @@ impl EthereumMachine {
     ///
     /// Introduced by EIP1559 to support new market fee mechanism.
     ///
-    /// Modified for xDai chain to have an ability to set constant base fee
+    /// Modified for xDai chain to have an ability to set min base fee
-    /// through eip1559BaseFeeFixedValue spec option. The modification made
+    /// through eip1559BaseFeeMinValue spec option. The modification made
     /// in v3.3.0-rc.14
     pub fn calc_base_fee(&self, parent: &Header) -> Option<U256> {
         // Block eip1559_transition - 1 has base_fee = None
@@ -476,22 +476,22 @@ impl EthereumMachine {
             return None;
         }
 
-        // If we use base fee constant value, ignore the code below
+        let base_fee_min_value =
-        if parent.number() + 1 >= self.params().eip1559_base_fee_fixed_value_transition {
+            if parent.number() + 1 >= self.params().eip1559_base_fee_min_value_transition {
-            let base_fee_fixed_value = match self.params().eip1559_base_fee_fixed_value {
+                match self.params().eip1559_base_fee_min_value {
-                None => panic!("Base fee fixed value must be set in spec."),
+                    None => panic!("Base fee min value must be set in spec."),
-                Some(fixed_value) => fixed_value,
+                    Some(min_value) => min_value,
-            };
-            return Some(base_fee_fixed_value);
                 }
+            } else {
+                U256::zero()
+            };
 
         // Block eip1559_transition has base_fee = self.params().eip1559_base_fee_initial_value
         if parent.number() + 1 == self.params().eip1559_transition {
-            let base_fee_initial_value = match self.params().eip1559_base_fee_initial_value {
+            return Some(max(
-                None => panic!("Base fee initial value must be set in spec."),
+                self.params().eip1559_base_fee_initial_value,
-                Some(initial_value) => initial_value,
+                base_fee_min_value,
-            };
+            ));
-            return Some(base_fee_initial_value);
         }
 
         // Block eip1559_transition + 1 has base_fee = calculated
@@ -509,21 +509,23 @@ impl EthereumMachine {
             panic!("Can't calculate base fee if parent gas target is zero.");
         }
 
-        if parent.gas_used() == &parent_gas_target {
+        let result = if parent.gas_used() == &parent_gas_target {
-            Some(parent_base_fee)
+            parent_base_fee
         } else if parent.gas_used() > &parent_gas_target {
             let gas_used_delta = parent.gas_used() - parent_gas_target;
             let base_fee_per_gas_delta = max(
                 parent_base_fee * gas_used_delta / parent_gas_target / base_fee_denominator,
                 U256::from(1),
             );
-            Some(parent_base_fee + base_fee_per_gas_delta)
+            parent_base_fee + base_fee_per_gas_delta
         } else {
             let gas_used_delta = parent_gas_target - parent.gas_used();
             let base_fee_per_gas_delta =
                 parent_base_fee * gas_used_delta / parent_gas_target / base_fee_denominator;
-            Some(max(parent_base_fee - base_fee_per_gas_delta, U256::zero()))
+            max(parent_base_fee - base_fee_per_gas_delta, U256::zero())
-        }
+        };
+
+        Some(max(result, base_fee_min_value))
     }
 }
 

crates/ethcore/src/spec/spec.rs

@@ -182,11 +182,11 @@ pub struct CommonParams {
     /// Elasticity multiplier
     pub eip1559_elasticity_multiplier: U256,
     /// Default value for the block base fee
-    pub eip1559_base_fee_initial_value: Option<U256>,
+    pub eip1559_base_fee_initial_value: U256,
-    /// Constant value for the block base fee.
+    /// Min value for the block base fee.
-    pub eip1559_base_fee_fixed_value: Option<U256>,
+    pub eip1559_base_fee_min_value: Option<U256>,
-    /// Block at which the constant value for the base fee starts to be used.
+    /// Block at which the min value for the base fee starts to be used.
-    pub eip1559_base_fee_fixed_value_transition: BlockNumber,
+    pub eip1559_base_fee_min_value_transition: BlockNumber,
     /// Address where EIP-1559 burnt fee will be accrued to.
     pub eip1559_fee_collector: Option<Address>,
     /// Block at which the fee collector should start being used.
@@ -464,10 +464,12 @@ impl From<ethjson::spec::Params> for CommonParams {
             eip1559_elasticity_multiplier: p
                 .eip1559_elasticity_multiplier
                 .map_or_else(U256::zero, Into::into),
-            eip1559_base_fee_initial_value: p.eip1559_base_fee_initial_value.map(Into::into),
+            eip1559_base_fee_initial_value: p
-            eip1559_base_fee_fixed_value: p.eip1559_base_fee_fixed_value.map(Into::into),
+                .eip1559_base_fee_initial_value
-            eip1559_base_fee_fixed_value_transition: p
+                .map_or_else(U256::zero, Into::into),
-                .eip1559_base_fee_fixed_value_transition
+            eip1559_base_fee_min_value: p.eip1559_base_fee_min_value.map(Into::into),
+            eip1559_base_fee_min_value_transition: p
+                .eip1559_base_fee_min_value_transition
                 .map_or_else(BlockNumber::max_value, Into::into),
             eip1559_fee_collector: p.eip1559_fee_collector.map(Into::into),
             eip1559_fee_collector_transition: p
@@ -749,7 +751,7 @@ impl Spec {
             params.max_code_size_transition,
             params.transaction_permission_contract_transition,
             params.eip1559_fee_collector_transition,
-            params.eip1559_base_fee_fixed_value_transition,
+            params.eip1559_base_fee_min_value_transition,
         ];
         // BUG: Rinkeby has homestead transition at block 1 but we can't reflect that in specs for non-Ethash networks
         if params.network_id == 0x4 {

crates/ethjson/src/spec/params.rs

@@ -158,10 +158,10 @@ pub struct Params {
     pub eip1559_elasticity_multiplier: Option<Uint>,
     /// Default value for the block base fee
     pub eip1559_base_fee_initial_value: Option<Uint>,
-    /// Constant value for the block base fee.
+    /// Min value for the block base fee.
-    pub eip1559_base_fee_fixed_value: Option<Uint>,
+    pub eip1559_base_fee_min_value: Option<Uint>,
-    /// Block at which the constant value for the base fee starts to be used.
+    /// Block at which the min value for the base fee starts to be used.
-    pub eip1559_base_fee_fixed_value_transition: Option<Uint>,
+    pub eip1559_base_fee_min_value_transition: Option<Uint>,
     /// Address where EIP-1559 burnt fee will be accrued to.
     pub eip1559_fee_collector: Option<Address>,
     /// Block at which the fee collector should start being used.