feat(randomBytes): adding support to generate different bytes via Rng…

…Core (#8996)

* feat(randomBytes): adding support to generate different bytes via RngCore

Signed-off-by: Abhishekkochar <[email protected]>

* Added needed changes to util file

Signed-off-by: Abhishekkochar <[email protected]>

* Added support to get random 4 and 8 bytes

Signed-off-by: Abhishekkochar <[email protected]>

* Refractor code to suggested changes

Signed-off-by: Abhishekkochar <[email protected]>

* Fixed import with B32

Signed-off-by: Abhishekkochar <[email protected]>

* updated cheatcodes.json file

Signed-off-by: Abhishekkochar <[email protected]>

* docs

---------

Signed-off-by: Abhishekkochar <[email protected]>
Co-authored-by: DaniPopes <[email protected]>

crates/cheatcodes/spec/src/vm.rs

@@ -2405,30 +2405,38 @@ interface Vm {
     #[cheatcode(group = Utilities)]
     function randomUint(uint256 min, uint256 max) external returns (uint256);
 
-    /// Returns an random `uint256` value of given bits.
+    /// Returns a random `uint256` value of given bits.
     #[cheatcode(group = Utilities)]
     function randomUint(uint256 bits) external view returns (uint256);
 
     /// Returns a random `address`.
     #[cheatcode(group = Utilities)]
     function randomAddress() external returns (address);
 
-    /// Returns an random `int256` value.
+    /// Returns a random `int256` value.
     #[cheatcode(group = Utilities)]
     function randomInt() external view returns (int256);
 
-    /// Returns an random `int256` value of given bits.
+    /// Returns a random `int256` value of given bits.
     #[cheatcode(group = Utilities)]
     function randomInt(uint256 bits) external view returns (int256);
 
-    /// Returns an random `bool`.
+    /// Returns a random `bool`.
     #[cheatcode(group = Utilities)]
     function randomBool() external view returns (bool);
 
-    /// Returns an random byte array value of the given length.
+    /// Returns a random byte array value of the given length.
     #[cheatcode(group = Utilities)]
     function randomBytes(uint256 len) external view returns (bytes memory);
 
+    /// Returns a random fixed-size byte array of length 4.
+    #[cheatcode(group = Utilities)]
+    function randomBytes4() external view returns (bytes4);
+
+    /// Returns a random fixed-size byte array of length 8.
+    #[cheatcode(group = Utilities)]
+    function randomBytes8() external view returns (bytes8);
+
     /// Pauses collection of call traces. Useful in cases when you want to skip tracing of
     /// complex calls which are not useful for debugging.
     #[cheatcode(group = Utilities)]

crates/cheatcodes/src/utils.rs

@@ -2,7 +2,7 @@
 
 use crate::{Cheatcode, Cheatcodes, CheatcodesExecutor, CheatsCtxt, Result, Vm::*};
 use alloy_dyn_abi::{DynSolType, DynSolValue};
-use alloy_primitives::{map::HashMap, U256};
+use alloy_primitives::{aliases::B32, map::HashMap, B64, U256};
 use alloy_sol_types::SolValue;
 use foundry_common::ens::namehash;
 use foundry_evm_core::constants::DEFAULT_CREATE2_DEPLOYER;
@@ -133,6 +133,20 @@ impl Cheatcode for randomBytesCall {
     }
 }
 
+impl Cheatcode for randomBytes4Call {
+    fn apply(&self, state: &mut Cheatcodes) -> Result {
+        let rand_u32 = state.rng().next_u32();
+        Ok(B32::from(rand_u32).abi_encode())
+    }
+}
+
+impl Cheatcode for randomBytes8Call {
+    fn apply(&self, state: &mut Cheatcodes) -> Result {
+        let rand_u64 = state.rng().next_u64();
+        Ok(B64::from(rand_u64).abi_encode())
+    }
+}
+
 impl Cheatcode for pauseTracingCall {
     fn apply_full(
         &self,

testdata/default/cheats/RandomBytes.t.sol

@@ -0,0 +1,22 @@
+// SPDX-License-Identifier: MIT OR Apache-2.0
+pragma solidity 0.8.18;
+
+import "ds-test/test.sol";
+import "cheats/Vm.sol";
+
+contract RandomBytes is DSTest {
+    Vm constant vm = Vm(HEVM_ADDRESS);
+
+    function testRandomBytes4() public {
+        vm.randomBytes4();
+    }
+
+    function testRandomBytes8() public {
+        vm.randomBytes8();
+    }
+
+    function testFillrandomBytes() public view {
+        uint256 len = 16;
+        vm.randomBytes(len);
+    }
+}