feat(forge): blobbasefee cheatcode (#7598)

* feat(forge): blobbasefee cheatcode

* updated comments

* nits

* moved test

* chore: add cancun test

---------

Co-authored-by: Matthias Seitz <matthias.seitz@outlook.de>

crates/cheatcodes/spec/src/vm.rs

@@ -402,6 +402,17 @@ interface Vm {
     #[cheatcode(group = Evm, safety = Safe)]
     function getBlockTimestamp() external view returns (uint256 timestamp);
 
+    /// Sets `block.blobbasefee`
+    #[cheatcode(group = Evm, safety = Unsafe)]
+    function blobBaseFee(uint256 newBlobBaseFee) external;
+
+    /// Gets the current `block.blobbasefee`.
+    /// You should use this instead of `block.blobbasefee` if you use `vm.blobBaseFee`, as `block.blobbasefee` is assumed to be constant across a transaction,
+    /// and as a result will get optimized out by the compiler.
+    /// See https://github.com/foundry-rs/foundry/issues/6180
+    #[cheatcode(group = Evm, safety = Safe)]
+    function getBlobBaseFee() external view returns (uint256 blobBaseFee);
+
     // -------- Account State --------
 
     /// Sets an address' balance.

crates/cheatcodes/src/evm.rs

@@ -328,6 +328,26 @@ impl Cheatcode for getBlockTimestampCall {
     }
 }
 
+impl Cheatcode for blobBaseFeeCall {
+    fn apply_full<DB: DatabaseExt>(&self, ccx: &mut CheatsCtxt<DB>) -> Result {
+        let Self { newBlobBaseFee } = self;
+        ensure!(
+            ccx.ecx.spec_id() >= SpecId::CANCUN,
+            "`blobBaseFee` is not supported before the Cancun hard fork; \
+             see EIP-4844: https://eips.ethereum.org/EIPS/eip-4844"
+        );
+        ccx.ecx.env.block.set_blob_excess_gas_and_price((*newBlobBaseFee).to());
+        Ok(Default::default())
+    }
+}
+
+impl Cheatcode for getBlobBaseFeeCall {
+    fn apply_full<DB: DatabaseExt>(&self, ccx: &mut CheatsCtxt<DB>) -> Result {
+        let Self {} = self;
+        Ok(ccx.ecx.env.block.get_blob_excess_gas().unwrap_or(0).abi_encode())
+    }
+}
+
 impl Cheatcode for dealCall {
     fn apply_full<DB: DatabaseExt>(&self, ccx: &mut CheatsCtxt<DB>) -> Result {
         let Self { account: address, newBalance: new_balance } = *self;

crates/forge/tests/it/cheats.rs

@@ -2,7 +2,10 @@
 
 use crate::{
     config::*,
-    test_helpers::{ForgeTestData, RE_PATH_SEPARATOR, TEST_DATA_DEFAULT, TEST_DATA_MULTI_VERSION},
+    test_helpers::{
+        ForgeTestData, RE_PATH_SEPARATOR, TEST_DATA_CANCUN, TEST_DATA_DEFAULT,
+        TEST_DATA_MULTI_VERSION,
+    },
 };
 use foundry_config::{fs_permissions::PathPermission, FsPermissions};
 use foundry_test_utils::Filter;
@@ -50,3 +53,8 @@ async fn test_cheats_local_default_isolated() {
 async fn test_cheats_local_multi_version() {
     test_cheats_local(&TEST_DATA_MULTI_VERSION).await
 }
+
+#[tokio::test(flavor = "multi_thread")]
+async fn test_cheats_local_cancun() {
+    test_cheats_local(&TEST_DATA_CANCUN).await
+}

crates/forge/tests/it/test_helpers.rs

@@ -2,8 +2,8 @@
 
 use alloy_primitives::U256;
 use forge::{
-    inspectors::CheatsConfig, MultiContractRunner, MultiContractRunnerBuilder, TestOptions,
-    TestOptionsBuilder,
+    inspectors::CheatsConfig, revm::primitives::SpecId, MultiContractRunner,
+    MultiContractRunnerBuilder, TestOptions, TestOptionsBuilder,
 };
 use foundry_compilers::{
     artifacts::{Libraries, Settings},
@@ -46,6 +46,11 @@ impl fmt::Display for ForgeTestProfile {
 }
 
 impl ForgeTestProfile {
+    /// Returns true if the profile is Cancun.
+    pub fn is_cancun(&self) -> bool {
+        matches!(self, Self::Cancun)
+    }
+
     pub fn root(&self) -> PathBuf {
         PathBuf::from(TESTDATA)
     }
@@ -147,7 +152,7 @@ impl ForgeTestProfile {
             "fork/Fork.t.sol:DssExecLib:0xfD88CeE74f7D78697775aBDAE53f9Da1559728E4".to_string(),
         ];
 
-        if matches!(self, Self::Cancun) {
+        if self.is_cancun() {
             config.evm_version = EvmVersion::Cancun;
         }
 
@@ -162,6 +167,7 @@ pub struct ForgeTestData {
     pub test_opts: TestOptions,
     pub evm_opts: EvmOpts,
     pub config: Config,
+    pub profile: ForgeTestProfile,
 }
 
 impl ForgeTestData {
@@ -175,15 +181,20 @@ impl ForgeTestData {
         let config = profile.config();
         let evm_opts = profile.evm_opts();
 
-        Self { project, output, test_opts, evm_opts, config }
+        Self { project, output, test_opts, evm_opts, config, profile }
     }
 
     /// Builds a base runner
     pub fn base_runner(&self) -> MultiContractRunnerBuilder {
         init_tracing();
-        MultiContractRunnerBuilder::default()
+        let mut runner = MultiContractRunnerBuilder::default()
             .sender(self.evm_opts.sender)
-            .with_test_options(self.test_opts.clone())
+            .with_test_options(self.test_opts.clone());
+        if self.profile.is_cancun() {
+            runner = runner.evm_spec(SpecId::CANCUN);
+        }
+
+        runner
     }
 
     /// Builds a non-tracing runner

testdata/cancun/cheats/BlobBaseFee.t.sol

@@ -0,0 +1,14 @@
+// SPDX-License-Identifier: MIT OR Apache-2.0
+pragma solidity ^0.8.25;
+
+import "ds-test/test.sol";
+import "cheats/Vm.sol";
+
+contract BlobBaseFeeTest is DSTest {
+    Vm constant vm = Vm(HEVM_ADDRESS);
+
+    function test_blob_base_fee() public {
+        vm.blobBaseFee(6969);
+        assertEq(vm.getBlobBaseFee(), 6969);
+    }
+}