Place demo_offence dispatchable behind root origin check

pallets/slashing/src/lib.rs

@@ -85,13 +85,16 @@ pub mod pallet {
     // Dispatchable functions must be annotated with a weight and must return a DispatchResult.
     #[pallet::call]
     impl<T: Config> Pallet<T> {
-        /// An example dispatchable that may throw a custom error.
+        /// A helper to trigger an offence.
+        ///
+        // # Note
+        //
+        // This is only used for demo purposes and should be removed before launch.
         #[pallet::call_index(0)]
         #[pallet::weight(10_000 + T::DbWeight::get().reads_writes(1,1).ref_time())]
-        pub fn demo_offence(origin: OriginFor<T>, offenders: Vec<T::AccountId>) -> DispatchResult {
-            // TODO remove this function, it is for demo purposes only
-            let who = ensure_signed(origin)?;
-            Self::do_offence(who, offenders)?;
+        pub fn demo_offence(origin: OriginFor<T>, reporter: T::AccountId, offenders: Vec<T::AccountId>) -> DispatchResult {
+            let _ = ensure_root(origin)?;
+            Self::do_offence(reporter, offenders)?;
             Ok(())
         }
     }

pallets/slashing/src/tests.rs

@@ -1,4 +1,4 @@
-use frame_support::assert_ok;
+use frame_support::{assert_ok, assert_err};
 use sp_runtime::Perbill;
 use sp_staking::offence::Offence;
 
@@ -18,13 +18,26 @@ fn offence_test() {
     new_test_ext().execute_with(|| {
         assert_ok!(Staking::force_new_era_always(RuntimeOrigin::root()));
         assert!(Session::validators().contains(&1));
+
         // slash would cause min validators to drop below min validators no offence
-        assert_ok!(Slashing::demo_offence(RuntimeOrigin::signed(1), vec![1u64, 2u64]));
+        assert_ok!(Slashing::demo_offence(RuntimeOrigin::root(), 1, vec![1u64, 2u64]));
         let mut offences = OFFENCES.with(|l| l.replace(vec![]));
         assert_eq!(offences.len(), 0);
+
         // causes offence
-        assert_ok!(Slashing::demo_offence(RuntimeOrigin::signed(1), vec![1u64]));
+        assert_ok!(Slashing::demo_offence(RuntimeOrigin::root(), 1, vec![1u64]));
         offences = OFFENCES.with(|l| l.replace(vec![]));
         assert_eq!(offences.len(), 1);
     });
 }
+
+#[test]
+fn signed_origin_cannot_initiate_demo_offence() {
+    new_test_ext().execute_with(|| {
+        assert_err!(
+            Slashing::demo_offence(RuntimeOrigin::signed(1), 1, vec![1u64, 2u64]),
+            sp_runtime::DispatchError::BadOrigin
+        );
+    })
+}
+