feat(cheats): add vm.getRawBlockHeader(blockNumber) (foundry-rs#11082)

* feat: add `getRawBlockHeader` cheat

* Update testdata/default/cheats/GetRawBlockHeader.t.sol

Co-authored-by: Matthias Seitz <[email protected]>

* Update testdata/default/cheats/GetRawBlockHeader.t.sol

Co-authored-by: Matthias Seitz <[email protected]>

* Fix fmt

---------

Co-authored-by: grandizzy <[email protected]>
Co-authored-by: Matthias Seitz <[email protected]>
Co-authored-by: grandizzy <[email protected]>

Author: 3 people

crates/cheatcodes/assets/cheatcodes.json

@@ -522,6 +522,11 @@ interface Vm {
     #[cheatcode(group = Evm, safety = Safe)]
     function getBlockTimestamp() external view returns (uint256 timestamp);
 
+    /// Gets the RLP encoded block header for a given block number.
+    /// Returns the block header in the same format as `cast block <block_number> --raw`.
+    #[cheatcode(group = Evm, safety = Safe)]
+    function getRawBlockHeader(uint256 blockNumber) external view returns (bytes memory rlpHeader);
+
     /// Sets `block.blobbasefee`
     #[cheatcode(group = Evm, safety = Unsafe)]
     function blobBaseFee(uint256 newBlobBaseFee) external;

crates/cheatcodes/spec/src/vm.rs

@@ -266,6 +266,33 @@ impl Cheatcode for eth_getLogsCall {
     }
 }
 
+impl Cheatcode for getRawBlockHeaderCall {
+    fn apply_stateful(&self, ccx: &mut CheatsCtxt) -> Result {
+        let Self { blockNumber } = self;
+        let url = ccx
+            .ecx
+            .journaled_state
+            .database
+            .active_fork_url()
+            .ok_or_else(|| fmt_err!("no active fork"))?;
+        let provider = ProviderBuilder::new(&url).build()?;
+        let block_number = u64::try_from(blockNumber)
+            .map_err(|_| fmt_err!("block number must be less than 2^64"))?;
+        let block =
+            foundry_common::block_on(async move { provider.get_block(block_number.into()).await })
+                .map_err(|e| fmt_err!("failed to get block: {e}"))?
+                .ok_or_else(|| fmt_err!("block {block_number} not found"))?;
+
+        let header: alloy_consensus::Header = block
+            .into_inner()
+            .header
+            .inner
+            .try_into_header()
+            .map_err(|e| fmt_err!("failed to convert to header: {e}"))?;
+        Ok(alloy_rlp::encode(&header).abi_encode())
+    }
+}
+
 /// Creates and then also selects the new fork
 fn create_select_fork(ccx: &mut CheatsCtxt, url_or_alias: &str, block: Option<u64>) -> Result {
     check_broadcast(ccx.state)?;

crates/cheatcodes/src/evm/fork.rs

@@ -0,0 +1,18 @@
+// SPDX-License-Identifier: MIT OR Apache-2.0
+pragma solidity ^0.8.18;
+
+import "ds-test/test.sol";
+import "cheats/Vm.sol";
+
+contract GetRawBlockHeaderTest is DSTest {
+    Vm constant vm = Vm(HEVM_ADDRESS);
+
+    function testGetRawBlockHeaderWithFork() public {
+        vm.createSelectFork("mainnet");
+        assertEq(
+            keccak256(vm.getRawBlockHeader(22985278)),
+            // `cast keccak256 $(cast block 22985278 --raw)`
+            0x492419d85d2817f50577807a287742fbdcaae00ce89f2ea885e419ee4493b00f
+        );
+    }
+}