add RLP cheats

crates/cheatcodes/spec/src/vm.rs

@@ -2946,6 +2946,13 @@ interface Vm {
     /// Generates a ready-to-sign digest of human-readable typed data following the EIP-712 standard.
     #[cheatcode(group = Utilities)]
     function eip712HashTypedData(string calldata jsonData) external pure returns (bytes32 digest);
+
+    /// RLP encodes a list of bytes into an RLP payload.
+    #[cheatcode(group = Utilities)]
+    function toRlp(bytes[] calldata data) external pure returns (bytes memory);
+    /// RLP decodes an RLP payload into a list of bytes.
+    #[cheatcode(group = Utilities)]
+    function fromRlp(bytes calldata rlp) external pure returns (bytes[] memory data);
 }
 }
 

crates/cheatcodes/src/utils.rs

@@ -4,6 +4,7 @@ use crate::{Cheatcode, Cheatcodes, CheatcodesExecutor, CheatsCtxt, Result, Vm::*
 use alloy_dyn_abi::{DynSolType, DynSolValue, Resolver, TypedData, eip712_parser::EncodeType};
 use alloy_ens::namehash;
 use alloy_primitives::{B64, Bytes, U256, aliases::B32, keccak256, map::HashMap};
+use alloy_rlp::{Decodable, Encodable};
 use alloy_sol_types::SolValue;
 use foundry_common::{TYPE_BINDING_PREFIX, fs};
 use foundry_config::fs_permissions::FsAccessKind;
@@ -470,3 +471,25 @@ fn get_struct_hash(primary: &str, type_def: &String, abi_encoded_data: &Bytes) -
 
     Ok(keccak256(&bytes_to_hash).to_vec())
 }
+
+impl Cheatcode for toRlpCall {
+    fn apply(&self, _state: &mut Cheatcodes) -> Result {
+        let Self { data } = self;
+
+        let mut buf = Vec::new();
+        data.encode(&mut buf);
+
+        Ok(Bytes::from(buf).abi_encode())
+    }
+}
+
+impl Cheatcode for fromRlpCall {
+    fn apply(&self, _state: &mut Cheatcodes) -> Result {
+        let Self { rlp } = self;
+
+        let decoded: Vec<Bytes> = Vec::<Bytes>::decode(&mut rlp.as_ref())
+            .map_err(|e| fmt_err!("Failed to decode RLP: {e}"))?;
+
+        Ok(decoded.abi_encode())
+    }
+}

testdata/default/cheats/Rlp.t.sol

@@ -0,0 +1,48 @@
+// SPDX-License-Identifier: MIT OR Apache-2.0
+pragma solidity ^0.8.18;
+
+import "ds-test/test.sol";
+import "cheats/Vm.sol";
+
+contract Rlp is DSTest {
+    Vm constant vm = Vm(HEVM_ADDRESS);
+
+    function testToRlp() public {
+        bytes[] memory data = new bytes[](2);
+        data[0] = hex"01";
+        data[1] = hex"02";
+
+        bytes memory rlp = vm.toRlp(data);
+
+        // Assert the expected RLP encoding for [0x01, 0x02]
+        // 0xc2 = list with 2 bytes total length
+        // 0x01 = first byte
+        // 0x02 = second byte
+        assertEq(rlp, hex"c20102");
+    }
+
+    function testFromRlp() public {
+        // RLP encoded [0x01, 0x02]
+        bytes memory rlp = hex"c20102";
+
+        bytes[] memory decoded = vm.fromRlp(rlp);
+        assertEq(decoded.length, 2);
+        assertEq(decoded[0], hex"01");
+        assertEq(decoded[1], hex"02");
+    }
+
+    function testRoundTrip() public {
+        bytes[] memory original = new bytes[](3);
+        original[0] = hex"deadbeef";
+        original[1] = hex"cafebabe";
+        original[2] = hex"01020304";
+
+        bytes memory rlp = vm.toRlp(original);
+        bytes[] memory decoded = vm.fromRlp(rlp);
+
+        assertEq(decoded.length, original.length);
+        for (uint256 i = 0; i < original.length; i++) {
+            assertEq(decoded[i], original[i]);
+        }
+    }
+}