feat: support numeric chain keys

Author: 0xrusowsky

crates/config/src/fork_config.rs

@@ -13,7 +13,7 @@ pub struct ForkConfigs(pub HashMap<String, ForkChainConfig>);
 
 impl ForkConfigs {
     /// Resolve environment variables in all fork config fields
-    pub fn resolve_env_vars(&mut self) -> Result<(), ExtractConfigError> {
+    fn resolve_env_vars(&mut self) -> Result<(), ExtractConfigError> {
         for (name, fork_config) in &mut self.0 {
             // Take temporary ownership of the config, so that it can be consumed.
             let config = std::mem::take(fork_config);
@@ -33,6 +33,47 @@ impl ForkConfigs {
 
         Ok(())
     }
+
+    /// Normalize fork config chains, so that all have `alloy_chain::NamedChain` compatible names.
+    fn normalize_keys(&mut self) -> Result<(), ExtractConfigError> {
+        let mut normalized = HashMap::new();
+
+        for (key, config) in std::mem::take(&mut self.0) {
+            // Determine the canonical key for this entry
+            let canonical_key = if let Ok(chain_id) = key.parse::<u64>() {
+                if let Some(named) = alloy_chains::Chain::from_id(chain_id).named() {
+                    named.as_str().to_string()
+                } else {
+                    return Err(ExtractConfigError::new(figment::Error::from(format!(
+                        "chain id '{key}' is not supported by 'alloy_chains'.",
+                    ))));
+                }
+            } else if let Ok(named) = key.parse::<alloy_chains::NamedChain>() {
+                named.as_str().to_string()
+            } else {
+                return Err(ExtractConfigError::new(figment::Error::from(format!(
+                    "chain name '{key}' is not supported by 'alloy_chains'.",
+                ))));
+            };
+
+            // Insert and check for conflicts
+            if normalized.insert(canonical_key, config).is_some() {
+                return Err(ExtractConfigError::new(figment::Error::from(
+                    "duplicate fork configuration.",
+                )));
+            }
+        }
+
+        self.0 = normalized;
+        Ok(())
+    }
+
+    /// Normalize fork config chains and resolve environment variables in all configured fields.
+    pub fn normalize_and_resolve(&mut self) -> Result<(), ExtractConfigError> {
+        self.resolve_env_vars()?;
+        self.normalize_keys()?;
+        Ok(())
+    }
 }
 
 impl Deref for ForkConfigs {

crates/config/src/lib.rs

@@ -689,7 +689,7 @@ impl Config {
         add_profile(&config.profile);
 
         config.normalize_optimizer_settings();
-        config.forks.resolve_env_vars()?;
+        config.forks.normalize_and_resolve()?;
 
         Ok(config)
     }

crates/forge/tests/cli/script.rs

@@ -3243,7 +3243,7 @@ forgetest_init!(can_access_fork_config_chain_ids, |prj, cmd| {
         config.forks = ForkConfigs(
             vec![
                 (
-                    "mainnet".to_string(),
+                    "1".to_string(),
                     ForkChainConfig {
                         rpc_endpoint: Some(RpcEndpoint::new(RpcEndpointUrl::Url(
                             "mainnet-rpc".to_string(),
@@ -3280,7 +3280,7 @@ forgetest_init!(can_access_fork_config_chain_ids, |prj, cmd| {
                     },
                 ),
                 (
-                    "optimism".to_string(),
+                    "10".to_string(),
                     ForkChainConfig {
                         rpc_endpoint: None,
                         vars: vec![