fix check when allow death (#559)

tokens/src/lib.rs

@@ -597,7 +597,7 @@ impl<T: Config> Pallet<T> {
 				Self::ensure_can_withdraw(currency_id, from, amount)?;
 
 				let allow_death = existence_requirement == ExistenceRequirement::AllowDeath;
-				let allow_death = allow_death && !frame_system::Pallet::<T>::is_provider_required(from);
+				let allow_death = allow_death && frame_system::Pallet::<T>::can_dec_provider(from);
 				// if from_account does not allow death and non_zero total is below existential
 				// deposit, would return an error.
 				ensure!(allow_death || from_account.total() >= ed, Error::<T>::KeepAlive);
@@ -1285,7 +1285,7 @@ where
 
 			let ed = T::ExistentialDeposits::get(&currency_id);
 			let allow_death = liveness == ExistenceRequirement::AllowDeath;
-			let allow_death = allow_death && !frame_system::Pallet::<T>::is_provider_required(who);
+			let allow_death = allow_death && frame_system::Pallet::<T>::can_dec_provider(who);
 			ensure!(allow_death || account.total() >= ed, Error::<T>::KeepAlive);
 
 			Ok(())

tokens/src/tests.rs

@@ -340,6 +340,26 @@ fn transfer_all_should_work() {
 		});
 }
 
+#[test]
+fn transfer_failed_when_allow_death_but_cannot_dec_provider() {
+	ExtBuilder::default()
+		.one_hundred_for_alice_n_bob()
+		.build()
+		.execute_with(|| {
+			assert_eq!(System::can_dec_provider(&ALICE), true);
+			assert_ok!(System::inc_consumers(&ALICE));
+			assert_eq!(System::can_dec_provider(&ALICE), false);
+			assert_noop!(
+				Tokens::transfer(Some(ALICE).into(), BOB, DOT, 100),
+				Error::<Runtime>::KeepAlive
+			);
+
+			assert_ok!(Tokens::deposit(BTC, &ALICE, 100));
+			assert_eq!(System::can_dec_provider(&ALICE), true);
+			assert_ok!(Tokens::transfer(Some(ALICE).into(), BOB, DOT, 100));
+		});
+}
+
 #[test]
 fn deposit_should_work() {
 	ExtBuilder::default()
@@ -593,6 +613,34 @@ fn currency_adapter_ensure_currency_adapter_should_work() {
 		});
 }
 
+#[test]
+fn currency_adapter_withdraw_failed_when_allow_death_but_cannot_dec_provider() {
+	ExtBuilder::default()
+		.one_hundred_for_alice_n_bob()
+		.build()
+		.execute_with(|| {
+			assert_eq!(System::can_dec_provider(&ALICE), true);
+			assert_ok!(System::inc_consumers(&ALICE));
+			assert_eq!(System::can_dec_provider(&ALICE), false);
+			assert!(TreasuryCurrencyAdapter::withdraw(
+				&ALICE,
+				100,
+				WithdrawReasons::TRANSFER,
+				ExistenceRequirement::AllowDeath
+			)
+			.is_err());
+			assert_ok!(Tokens::deposit(BTC, &ALICE, 100));
+			assert_eq!(System::can_dec_provider(&ALICE), true);
+			assert!(TreasuryCurrencyAdapter::withdraw(
+				&ALICE,
+				100,
+				WithdrawReasons::TRANSFER,
+				ExistenceRequirement::AllowDeath
+			)
+			.is_ok());
+		});
+}
+
 #[test]
 fn currency_adapter_burn_must_work() {
 	ExtBuilder::default()