fix: derive block gas limit from rpc for forge script and anvil when forking

crates/anvil/src/config.rs

@@ -1173,6 +1173,8 @@ latest block number: {latest_block}"
         };
 
         let gas_limit = self.fork_gas_limit(&block);
+        self.gas_limit = Some(gas_limit);
+
         env.block = BlockEnv {
             number: U256::from(fork_block_number),
             timestamp: U256::from(block.header.timestamp),

crates/script/src/broadcast.rs

@@ -5,7 +5,9 @@ use crate::{
 use alloy_chains::Chain;
 use alloy_consensus::TxEnvelope;
 use alloy_eips::{eip2718::Encodable2718, BlockId};
-use alloy_network::{AnyNetwork, EthereumWallet, TransactionBuilder};
+use alloy_network::{
+    primitives::BlockTransactionsKind, AnyNetwork, EthereumWallet, TransactionBuilder,
+};
 use alloy_primitives::{
     map::{AddressHashMap, AddressHashSet},
     utils::format_units,
@@ -49,6 +51,20 @@ where
     Ok(())
 }
 
+pub async fn get_block_gas_limit(provider_url: &str, block_number: Option<u64>) -> Result<u64> {
+    let provider = try_get_http_provider(provider_url)
+        .wrap_err_with(|| format!("bad fork_url provider: {provider_url}"))?;
+
+    let block_id = block_number.map_or(BlockId::latest(), BlockId::number);
+    let block = provider.get_block(block_id, BlockTransactionsKind::Hashes).await?;
+
+    if let Some(block) = block {
+        Ok(block.header.gas_limit)
+    } else {
+        bail!("Failed to get block for block number: {}", block_number.unwrap_or_default())
+    }
+}
+
 pub async fn next_nonce(
     caller: Address,
     provider_url: &str,

crates/script/src/lib.rs

@@ -11,7 +11,7 @@ extern crate foundry_common;
 #[macro_use]
 extern crate tracing;
 
-use crate::runner::ScriptRunner;
+use crate::{broadcast::get_block_gas_limit, runner::ScriptRunner};
 use alloy_json_abi::{Function, JsonAbi};
 use alloy_primitives::{
     hex,
@@ -553,14 +553,19 @@ pub struct ScriptConfig {
 }
 
 impl ScriptConfig {
-    pub async fn new(config: Config, evm_opts: EvmOpts) -> Result<Self> {
+    pub async fn new(config: Config, mut evm_opts: EvmOpts) -> Result<Self> {
         let sender_nonce = if let Some(fork_url) = evm_opts.fork_url.as_ref() {
             next_nonce(evm_opts.sender, fork_url, evm_opts.fork_block_number).await?
         } else {
             // dapptools compatibility
             1
         };
 
+        if let Some(fork_url) = evm_opts.fork_url.as_ref() {
+            evm_opts.env.gas_limit =
+                get_block_gas_limit(fork_url, evm_opts.fork_block_number).await?.into();
+        }
+
         Ok(Self { config, evm_opts, sender_nonce, backends: HashMap::default() })
     }