fix(anvil): eth_gasPrice returned 1000000000 with --block-base-fee-per-gas 0, adds new --disable-min-priority-fee to return 0 (foundry-rs#9049)

* add new flag to disable min suggested priority fee: `--disable-min-priority-fee`

* documentation

* remove unnecessary value_name

Author: zerosnacks

crates/anvil/src/cmd.rs

@@ -254,6 +254,7 @@ impl NodeArgs {
             .fork_compute_units_per_second(compute_units_per_second)
             .with_eth_rpc_url(self.evm_opts.fork_url.map(|fork| fork.url))
             .with_base_fee(self.evm_opts.block_base_fee_per_gas)
+            .disable_min_priority_fee(self.evm_opts.disable_min_priority_fee)
             .with_storage_caching(self.evm_opts.no_storage_caching)
             .with_server_config(self.server_config)
             .with_host(self.host)
@@ -547,6 +548,10 @@ pub struct AnvilEvmArgs {
     )]
     pub block_base_fee_per_gas: Option<u64>,
 
+    /// Disable the enforcement of a minimum suggested priority fee.
+    #[arg(long, visible_alias = "no-priority-fee", help_heading = "Environment config")]
+    pub disable_min_priority_fee: bool,
+
     /// The chain ID.
     #[arg(long, alias = "chain", help_heading = "Environment config")]
     pub chain_id: Option<Chain>,

crates/anvil/src/config.rs

@@ -99,6 +99,8 @@ pub struct NodeConfig {
     pub gas_price: Option<u128>,
     /// Default base fee
     pub base_fee: Option<u64>,
+    /// If set to `true`, disables the enforcement of a minimum suggested priority fee
+    pub disable_min_priority_fee: bool,
     /// Default blob excess gas and price
     pub blob_excess_gas_and_price: Option<BlobExcessGasAndPrice>,
     /// The hardfork to use
@@ -432,6 +434,7 @@ impl Default for NodeConfig {
             fork_choice: None,
             account_generator: None,
             base_fee: None,
+            disable_min_priority_fee: false,
             blob_excess_gas_and_price: None,
             enable_tracing: true,
             enable_steps_tracing: false,
@@ -623,6 +626,13 @@ impl NodeConfig {
         self
     }
 
+    /// Disable the enforcement of a minimum suggested priority fee
+    #[must_use]
+    pub fn disable_min_priority_fee(mut self, disable_min_priority_fee: bool) -> Self {
+        self.disable_min_priority_fee = disable_min_priority_fee;
+        self
+    }
+
     /// Sets the init genesis (genesis.json)
     #[must_use]
     pub fn with_genesis(mut self, genesis: Option<Genesis>) -> Self {
@@ -994,6 +1004,7 @@ impl NodeConfig {
         let fees = FeeManager::new(
             cfg.handler_cfg.spec_id,
             self.get_base_fee(),
+            !self.disable_min_priority_fee,
             self.get_gas_price(),
             self.get_blob_excess_gas_and_price(),
         );

crates/anvil/src/eth/api.rs

@@ -592,7 +592,11 @@ impl EthApi {
     /// Returns the current gas price
     pub fn gas_price(&self) -> u128 {
         if self.backend.is_eip1559() {
-            (self.backend.base_fee() as u128).saturating_add(self.lowest_suggestion_tip())
+            if self.backend.is_min_priority_fee_enforced() {
+                (self.backend.base_fee() as u128).saturating_add(self.lowest_suggestion_tip())
+            } else {
+                self.backend.base_fee() as u128
+            }
         } else {
             self.backend.fees().raw_gas_price()
         }

crates/anvil/src/eth/backend/mem/mod.rs

@@ -668,6 +668,11 @@ impl Backend {
         self.fees.base_fee()
     }
 
+    /// Returns whether the minimum suggested priority fee is enforced
+    pub fn is_min_priority_fee_enforced(&self) -> bool {
+        self.fees.is_min_priority_fee_enforced()
+    }
+
     pub fn excess_blob_gas_and_price(&self) -> Option<BlobExcessGasAndPrice> {
         self.fees.excess_blob_gas_and_price()
     }

crates/anvil/src/eth/fees.rs

@@ -48,6 +48,8 @@ pub struct FeeManager {
     ///
     /// This value will be updated after a new block was mined
     base_fee: Arc<RwLock<u64>>,
+    /// Whether the minimum suggested priority fee is enforced
+    is_min_priority_fee_enforced: bool,
     /// Tracks the excess blob gas, and the base fee, for the next block post Cancun
     ///
     /// This value will be updated after a new block was mined
@@ -63,12 +65,14 @@ impl FeeManager {
     pub fn new(
         spec_id: SpecId,
         base_fee: u64,
+        is_min_priority_fee_enforced: bool,
         gas_price: u128,
         blob_excess_gas_and_price: BlobExcessGasAndPrice,
     ) -> Self {
         Self {
             spec_id,
             base_fee: Arc::new(RwLock::new(base_fee)),
+            is_min_priority_fee_enforced,
             gas_price: Arc::new(RwLock::new(gas_price)),
             blob_excess_gas_and_price: Arc::new(RwLock::new(blob_excess_gas_and_price)),
             elasticity: Arc::new(RwLock::new(default_elasticity())),
@@ -105,6 +109,10 @@ impl FeeManager {
         }
     }
 
+    pub fn is_min_priority_fee_enforced(&self) -> bool {
+        self.is_min_priority_fee_enforced
+    }
+
     /// Raw base gas price
     pub fn raw_gas_price(&self) -> u128 {
         *self.gas_price.read()