Adding try_state hook for Tips pallet

substrate/frame/tips/src/lib.rs

@@ -68,6 +68,7 @@ use sp_std::prelude::*;
 
 use codec::{Decode, Encode};
 use frame_support::{
+	ensure,
 	traits::{
 		ContainsLengthBound, Currency, EnsureOrigin, ExistenceRequirement::KeepAlive, Get,
 		OnUnbalanced, ReservableCurrency, SortedMembers,
@@ -76,6 +77,9 @@ use frame_support::{
 };
 use frame_system::pallet_prelude::BlockNumberFor;
 
+#[cfg(any(feature = "try-runtime", test))]
+use sp_runtime::TryRuntimeError;
+
 pub use pallet::*;
 pub use weights::WeightInfo;
 
@@ -465,6 +469,14 @@ pub mod pallet {
 			Ok(())
 		}
 	}
+
+	#[pallet::hooks]
+	impl<T: Config<I>, I: 'static> Hooks<BlockNumberFor<T>> for Pallet<T, I> {
+		#[cfg(feature = "try-runtime")]
+		fn try_state(_n: BlockNumberFor<T>) -> Result<(), TryRuntimeError> {
+			Self::do_try_state()
+		}
+	}
 }
 
 impl<T: Config<I>, I: 'static> Pallet<T, I> {
@@ -611,4 +623,25 @@ impl<T: Config<I>, I: 'static> Pallet<T, I> {
 			Tips::<T, I>::insert(hash, new_tip)
 		}
 	}
+
+	/// Ensure the correctness of the state of this pallet.
+	///
+	/// This should be valid before or after each state transition of this pallet.
+	///
+	/// ## Invariants:
+	///
+	/// If `OpenTip.finders_fee` is true, then OpenTip.deposit should be greater that zero.
+	#[cfg(any(feature = "try-runtime", test))]
+	pub fn do_try_state() -> Result<(), TryRuntimeError> {
+		for tips in Tips::<T, I>::iter_keys() {
+			let open_tip = Tips::<T, I>::get(&tips).unwrap();
+			if open_tip.finders_fee {
+				ensure!(
+					!open_tip.deposit.is_zero(),
+					TryRuntimeError::Other("finder's fee not present")
+				)
+			}
+		}
+		Ok(())
+	}
 }

substrate/frame/tips/src/tests.rs

@@ -192,7 +192,7 @@ impl Config for Test {
 	type Tippers = TenToFourteen;
 	type TipCountdown = ConstU64<1>;
 	type TipFindersFee = TipFindersFee;
-	type TipReportDepositBase = ConstU64<1>;
+	type TipReportDepositBase = ConstU64<0>;
 	type DataDepositPerByte = ConstU64<1>;
 	type MaxTipAmount = ConstU64<10_000_000>;
 	type RuntimeEvent = RuntimeEvent;
@@ -263,8 +263,8 @@ fn report_awesome_and_tip_works() {
 	new_test_ext().execute_with(|| {
 		Balances::make_free_balance_be(&Treasury::account_id(), 101);
 		assert_ok!(Tips::report_awesome(RuntimeOrigin::signed(0), b"awesome.dot".to_vec(), 3));
-		assert_eq!(Balances::reserved_balance(0), 12);
-		assert_eq!(Balances::free_balance(0), 88);
+		assert_eq!(Balances::reserved_balance(0), 11);
+		assert_eq!(Balances::free_balance(0), 89);
 
 		// other reports don't count.
 		assert_noop!(
@@ -290,8 +290,8 @@ fn report_awesome_from_beneficiary_and_tip_works() {
 	new_test_ext().execute_with(|| {
 		Balances::make_free_balance_be(&Treasury::account_id(), 101);
 		assert_ok!(Tips::report_awesome(RuntimeOrigin::signed(0), b"awesome.dot".to_vec(), 0));
-		assert_eq!(Balances::reserved_balance(0), 12);
-		assert_eq!(Balances::free_balance(0), 88);
+		assert_eq!(Balances::reserved_balance(0), 11);
+		assert_eq!(Balances::free_balance(0), 89);
 		let h = BlakeTwo256::hash_of(&(BlakeTwo256::hash(b"awesome.dot"), 0u128));
 		assert_ok!(Tips::tip(RuntimeOrigin::signed(10), h, 10));
 		assert_ok!(Tips::tip(RuntimeOrigin::signed(11), h, 10));
@@ -353,8 +353,8 @@ fn slash_tip_works() {
 
 		assert_ok!(Tips::report_awesome(RuntimeOrigin::signed(0), b"awesome.dot".to_vec(), 3));
 
-		assert_eq!(Balances::reserved_balance(0), 12);
-		assert_eq!(Balances::free_balance(0), 88);
+		assert_eq!(Balances::reserved_balance(0), 11);
+		assert_eq!(Balances::free_balance(0), 89);
 
 		let h = tip_hash();
 		assert_eq!(last_event(), TipEvent::NewTip { tip_hash: h });
@@ -364,11 +364,11 @@ fn slash_tip_works() {
 
 		// can remove from root.
 		assert_ok!(Tips::slash_tip(RuntimeOrigin::root(), h));
-		assert_eq!(last_event(), TipEvent::TipSlashed { tip_hash: h, finder: 0, deposit: 12 });
+		assert_eq!(last_event(), TipEvent::TipSlashed { tip_hash: h, finder: 0, deposit: 11 });
 
 		// tipper slashed
 		assert_eq!(Balances::reserved_balance(0), 0);
-		assert_eq!(Balances::free_balance(0), 88);
+		assert_eq!(Balances::free_balance(0), 89);
 	});
 }
 
@@ -654,3 +654,15 @@ fn report_awesome_and_tip_works_second_instance() {
 		assert_eq!(Balances::free_balance(&Treasury1::account_id()), 191);
 	});
 }
+
+#[test]
+fn try_state_invariant_works() {
+	new_test_ext().execute_with(|| {
+		use frame_support::pallet_prelude::DispatchError::Other;
+		Balances::make_free_balance_be(&Treasury::account_id(), 101);
+
+		assert_ok!(Tips::report_awesome(RuntimeOrigin::signed(0), b"".to_vec(), 3));
+
+		assert_eq!(Tips::do_try_state(), Err(Other("finder's fee not present")))
+	})
+}