fix(anvil): fix chain-id precedence (#10239)

Author: yash-atreya

crates/anvil/src/cmd.rs

@@ -223,13 +223,6 @@ impl NodeArgs {
             None => None,
         };
 
-        // --chain-id takes precedence over the genesis config
-        // if both are missing, use the default chain id
-        // <https://github.com/foundry-rs/foundry/issues/10059>
-        let chain_id = self
-            .evm
-            .chain_id
-            .map_or(self.init.as_ref().map_or(CHAIN_ID, |g| g.config.chain_id), |c| c.into());
         Ok(NodeConfig::default()
             .with_gas_limit(self.evm.gas_limit)
             .disable_block_gas_limit(self.evm.disable_block_gas_limit)
@@ -261,7 +254,7 @@ impl NodeArgs {
             .with_host(self.host)
             .set_silent(shell::is_quiet())
             .set_config_out(self.config_out)
-            .with_chain_id(Some(chain_id))
+            .with_chain_id(self.evm.chain_id)
             .with_transaction_order(self.order)
             .with_genesis(self.init)
             .with_steps_tracing(self.evm.steps_tracing)

crates/anvil/src/config.rs

@@ -1037,7 +1037,11 @@ impl NodeConfig {
 
         // if provided use all settings of `genesis.json`
         if let Some(ref genesis) = self.genesis {
-            env.cfg.chain_id = genesis.config.chain_id;
+            // --chain-id flag gets precedence over the genesis.json chain id
+            // <https://github.com/foundry-rs/foundry/issues/10059>
+            if self.chain_id.is_none() {
+                env.cfg.chain_id = genesis.config.chain_id;
+            }
             env.block.timestamp = U256::from(genesis.timestamp);
             if let Some(base_fee) = genesis.base_fee_per_gas {
                 env.block.basefee = U256::from(base_fee);

crates/anvil/tests/it/genesis.rs

@@ -1,14 +1,13 @@
 //! genesis.json tests
 
+use crate::fork::fork_config;
 use alloy_genesis::Genesis;
 use alloy_primitives::{Address, U256};
 use alloy_provider::Provider;
 use anvil::{spawn, NodeConfig};
 use std::str::FromStr;
 
-#[tokio::test(flavor = "multi_thread")]
-async fn can_apply_genesis() {
-    let genesis = r#"{
+const GENESIS: &str = r#"{
   "config": {
     "chainId": 19763,
     "homesteadBlock": 0,
@@ -35,7 +34,10 @@ async fn can_apply_genesis() {
   "parentHash": "0x0000000000000000000000000000000000000000000000000000000000000000"
 }
 "#;
-    let genesis: Genesis = serde_json::from_str(genesis).unwrap();
+
+#[tokio::test(flavor = "multi_thread")]
+async fn can_apply_genesis() {
+    let genesis: Genesis = serde_json::from_str(GENESIS).unwrap();
     let (_api, handle) = spawn(NodeConfig::test().with_genesis(Some(genesis))).await;
 
     let provider = handle.http_provider();
@@ -51,3 +53,49 @@ async fn can_apply_genesis() {
     let block_number = provider.get_block_number().await.unwrap();
     assert_eq!(block_number, 73u64);
 }
+
+// <https://github.com/foundry-rs/foundry/issues/10059>
+// <https://github.com/foundry-rs/foundry/issues/10238>
+#[tokio::test(flavor = "multi_thread")]
+async fn chain_id_precedence() {
+    // Order: --chain-id > fork-chain-id > Genesis > default.
+
+    // --chain-id > Genesis.
+    let genesis: Genesis = serde_json::from_str(GENESIS).unwrap();
+    let (_api, handle) =
+        spawn(NodeConfig::test().with_genesis(Some(genesis.clone())).with_chain_id(Some(300u64)))
+            .await;
+    let provider = handle.http_provider();
+    let chain_id = provider.get_chain_id().await.unwrap();
+    assert_eq!(chain_id, 300u64);
+
+    // fork > Genesis.
+    let (_api, handle) = spawn(fork_config().with_genesis(Some(genesis.clone()))).await;
+    let provider = handle.http_provider();
+    let chain_id = provider.get_chain_id().await.unwrap();
+    assert_eq!(chain_id, 1);
+
+    // --chain-id > fork.
+    let (_api, handle) = spawn(fork_config().with_chain_id(Some(300u64))).await;
+    let provider = handle.http_provider();
+    let chain_id = provider.get_chain_id().await.unwrap();
+    assert_eq!(chain_id, 300u64);
+
+    // fork
+    let (_api, handle) = spawn(fork_config()).await;
+    let provider = handle.http_provider();
+    let chain_id = provider.get_chain_id().await.unwrap();
+    assert_eq!(chain_id, 1);
+
+    // Genesis
+    let (_api, handle) = spawn(NodeConfig::test().with_genesis(Some(genesis))).await;
+    let provider = handle.http_provider();
+    let chain_id = provider.get_chain_id().await.unwrap();
+    assert_eq!(chain_id, 19763u64);
+
+    // default
+    let (_api, handle) = spawn(NodeConfig::test()).await;
+    let provider = handle.http_provider();
+    let chain_id = provider.get_chain_id().await.unwrap();
+    assert_eq!(chain_id, 31337);
+}