Add force remove vesting (paritytech#1982)

This PR exposes a `force_remove_vesting` through a ROOT call. 
See linked
[issue](paritytech#269)

---------

Co-authored-by: georgepisaltu <52418509+georgepisaltu@users.noreply.github.com>
Co-authored-by: command-bot <>
Co-authored-by: Dónal Murray <donal.murray@parity.io>

substrate/frame/vesting/src/benchmarking.rs

@@ -383,6 +383,33 @@ benchmarks! {
 		);
 	}
 
+force_remove_vesting_schedule {
+		let l in 0 .. MaxLocksOf::<T>::get() - 1;
+		let s in 2 .. T::MAX_VESTING_SCHEDULES;
+
+		let source: T::AccountId = account("source", 0, SEED);
+		let source_lookup: <T::Lookup as StaticLookup>::Source = T::Lookup::unlookup(source.clone());
+		T::Currency::make_free_balance_be(&source, BalanceOf::<T>::max_value());
+
+		let target: T::AccountId = account("target", 0, SEED);
+		let target_lookup: <T::Lookup as StaticLookup>::Source = T::Lookup::unlookup(target.clone());
+		T::Currency::make_free_balance_be(&target, T::Currency::minimum_balance());
+
+		// Give target existing locks.
+		add_locks::<T>(&target, l as u8);
+		let _ = add_vesting_schedules::<T>(target_lookup.clone(), s)?;
+
+		// The last vesting schedule.
+		let schedule_index = s - 1;
+	}: _(RawOrigin::Root, target_lookup, schedule_index)
+	verify {
+		assert_eq!(
+		Vesting::<T>::vesting(&target).unwrap().len(),
+			schedule_index as usize,
+			"Schedule count should reduce by 1"
+		);
+	}
+
 	impl_benchmark_test_suite!(
 		Vesting,
 		crate::mock::ExtBuilder::default().existential_deposit(256).build(),

substrate/frame/vesting/src/lib.rs

@@ -427,6 +427,36 @@ pub mod pallet {
 
 			Ok(())
 		}
+
+		/// Force remove a vesting schedule
+		///
+		/// The dispatch origin for this call must be _Root_.
+		///
+		/// - `target`: An account that has a vesting schedule
+		/// - `schedule_index`: The vesting schedule index that should be removed
+		#[pallet::call_index(5)]
+		#[pallet::weight(
+			T::WeightInfo::force_remove_vesting_schedule(MaxLocksOf::<T>::get(), T::MAX_VESTING_SCHEDULES)
+		)]
+		pub fn force_remove_vesting_schedule(
+			origin: OriginFor<T>,
+			target: <T::Lookup as StaticLookup>::Source,
+			schedule_index: u32,
+		) -> DispatchResultWithPostInfo {
+			ensure_root(origin)?;
+			let who = T::Lookup::lookup(target)?;
+
+			let schedules_count = Vesting::<T>::decode_len(&who).unwrap_or_default();
+			ensure!(schedule_index < schedules_count as u32, Error::<T>::InvalidScheduleParams);
+
+			Self::remove_vesting_schedule(&who, schedule_index)?;
+
+			Ok(Some(T::WeightInfo::force_remove_vesting_schedule(
+				MaxLocksOf::<T>::get(),
+				schedules_count as u32,
+			))
+			.into())
+		}
 	}
 }
 

substrate/frame/vesting/src/tests.rs

@@ -1155,3 +1155,39 @@ fn vested_transfer_less_than_existential_deposit_fails() {
 		);
 	});
 }
+
+#[test]
+fn remove_vesting_schedule() {
+	ExtBuilder::default().existential_deposit(ED).build().execute_with(|| {
+		assert_eq!(Balances::free_balance(&3), 256 * 30);
+		assert_eq!(Balances::free_balance(&4), 256 * 40);
+		// Account 4 should not have any vesting yet.
+		assert_eq!(Vesting::vesting(&4), None);
+		// Make the schedule for the new transfer.
+		let new_vesting_schedule = VestingInfo::new(
+			ED * 5,
+			(ED * 5) / 20, // Vesting over 20 blocks
+			10,
+		);
+		assert_ok!(Vesting::vested_transfer(Some(3).into(), 4, new_vesting_schedule));
+		// Now account 4 should have vesting.
+		assert_eq!(Vesting::vesting(&4).unwrap(), vec![new_vesting_schedule]);
+		// Account 4 has 5 * 256 locked.
+		assert_eq!(Vesting::vesting_balance(&4), Some(256 * 5));
+		// Verify only root can call.
+		assert_noop!(Vesting::force_remove_vesting_schedule(Some(4).into(), 4, 0), BadOrigin);
+		// Verify that root can remove the schedule.
+		assert_ok!(Vesting::force_remove_vesting_schedule(RawOrigin::Root.into(), 4, 0));
+		// Verify that last event is VestingCompleted.
+		System::assert_last_event(Event::VestingCompleted { account: 4 }.into());
+		// Appropriate storage is cleaned up.
+		assert!(!<VestingStorage<Test>>::contains_key(4));
+		// Check the vesting balance is zero.
+		assert_eq!(Vesting::vesting(&4), None);
+		// Verifies that trying to remove a schedule when it doesnt exist throws error.
+		assert_noop!(
+			Vesting::force_remove_vesting_schedule(RawOrigin::Root.into(), 4, 0),
+			Error::<Test>::InvalidScheduleParams
+		);
+	});
+}