Downgrade class

frame/utility/src/benchmarking.rs

@@ -86,5 +86,9 @@ benchmarks! {
 		assert_last_event::<T>(Event::BatchCompleted.into())
 	}
 
+	downgrade_class {
+		let call = Box::new(frame_system::Call::set_code_without_checks { code: vec![] }.into());
+	}: _(RawOrigin::Root, call)
+
 	impl_benchmark_test_suite!(Pallet, crate::tests::new_test_ext(), crate::tests::Test);
 }

frame/utility/src/lib.rs

@@ -489,6 +489,29 @@ pub mod pallet {
 			let res = call.dispatch_bypass_filter(frame_system::RawOrigin::Root.into());
 			res.map(|_| ()).map_err(|e| e.error)
 		}
+
+		/// Dispatch a function call with normal class.
+		///
+		/// This function sets the dispatch class of the call to normal by force.
+		///
+		/// The dispatch origin for this call must be _Root_.
+		#[pallet::call_index(6)]
+		#[pallet::weight({
+			let dispatch_info = call.get_dispatch_info();
+			(
+				T::WeightInfo::downgrade_class()
+					.saturating_add(dispatch_info.weight),
+				DispatchClass::Normal
+			)
+		})]
+		pub fn downgrade_class(
+			origin: OriginFor<T>,
+			call: Box<<T as Config>::RuntimeCall>,
+		) -> DispatchResult {
+			ensure_root(origin)?;
+			let res = call.dispatch_bypass_filter(frame_system::RawOrigin::Root.into());
+			res.map(|_| ()).map_err(|e| e.error)
+		}
 	}
 }
 

frame/utility/src/tests.rs

@@ -24,7 +24,7 @@ use super::*;
 use crate as utility;
 use frame_support::{
 	assert_err_ignore_postinfo, assert_noop, assert_ok,
-	dispatch::{DispatchError, DispatchErrorWithPostInfo, Dispatchable, Pays},
+	dispatch::{DispatchClass, DispatchError, DispatchErrorWithPostInfo, Dispatchable, Pays},
 	error::BadOrigin,
 	parameter_types, storage,
 	traits::{ConstU32, ConstU64, Contains, GenesisBuild},
@@ -937,3 +937,22 @@ fn with_weight_works() {
 		);
 	})
 }
+
+#[test]
+fn downgrade_class_works() {
+	new_test_ext().execute_with(|| {
+		let upgrade_code_call =
+			Box::new(RuntimeCall::System(frame_system::Call::set_code_without_checks {
+				code: vec![],
+			}));
+		// Class before is `Operational`.
+		assert_eq!(upgrade_code_call.get_dispatch_info().class, DispatchClass::Operational);
+
+		let with_weight_call = Call::<Test>::downgrade_class { call: upgrade_code_call };
+		// Class after is `Normal`.
+		assert_eq!(
+			with_weight_call.get_dispatch_info().class,
+			frame_support::dispatch::DispatchClass::Normal
+		);
+	})
+}