actually update deduct_block when paying rent (#2490)

* actually update deduct_block when paying rent

* add test

* remove println

* same block call test

* bump version

substrate/node/runtime/src/lib.rs

@@ -59,7 +59,7 @@ pub const VERSION: RuntimeVersion = RuntimeVersion {
 	impl_name: create_runtime_str!("substrate-node"),
 	authoring_version: 10,
 	spec_version: 72,
-	impl_version: 72,
+	impl_version: 73,
 	apis: RUNTIME_API_VERSIONS,
 };
 

substrate/srml/contract/src/rent.rs

@@ -55,10 +55,12 @@ fn try_evict_or_and_pay_rent<T: Trait>(
 		Some(ContractInfo::Alive(contract)) => contract,
 	};
 
+	let current_block_number = <system::Module<T>>::block_number();
+
 	// How much block has passed since the last deduction for the contract.
 	let blocks_passed = {
 		// Calculate an effective block number, i.e. after adjusting for handicap.
-		let effective_block_number = <system::Module<T>>::block_number().saturating_sub(handicap);
+		let effective_block_number = current_block_number.saturating_sub(handicap);
 		let n = effective_block_number.saturating_sub(contract.deduct_block);
 		if n.is_zero() {
 			// Rent has already been paid
@@ -125,11 +127,13 @@ fn try_evict_or_and_pay_rent<T: Trait>(
 			);
 
 			<ContractInfoOf<T>>::mutate(account, |contract| {
-				contract
+				let contract = contract
 					.as_mut()
 					.and_then(|c| c.as_alive_mut())
-					.expect("Dead or inexistent account has been exempt above; qed")
+					.expect("Dead or inexistent account has been exempt above; qed");
-					.rent_allowance -= imbalance.peek(); // rent_allowance is not exceeded
+
+				contract.rent_allowance -= imbalance.peek(); // rent_allowance is not exceeded
+				contract.deduct_block = current_block_number;
 			})
 		}
 

substrate/srml/contract/src/tests.rs

@@ -718,7 +718,31 @@ fn deduct_blocks() {
 				* 4; // blocks to rent
 			let bob_contract = super::ContractInfoOf::<Test>::get(BOB).unwrap().get_alive().unwrap();
 			assert_eq!(bob_contract.rent_allowance, 1_000 - rent);
+			assert_eq!(bob_contract.deduct_block, 5);
 			assert_eq!(Balances::free_balance(BOB), 30_000 - rent);
+
+			// Advance 7 blocks more
+			System::initialize(&12, &[0u8; 32].into(), &[0u8; 32].into());
+
+			// Trigger rent through call
+			assert_ok!(Contract::call(Origin::signed(ALICE), BOB, 0, 100_000, call::null()));
+
+			// Check result
+			let rent_2 = (8 + 4 - 2) // storage size = size_offset + deploy_set_storage - deposit_offset
+				* 4 // rent byte price
+				* 7; // blocks to rent
+			let bob_contract = super::ContractInfoOf::<Test>::get(BOB).unwrap().get_alive().unwrap();
+			assert_eq!(bob_contract.rent_allowance, 1_000 - rent - rent_2);
+			assert_eq!(bob_contract.deduct_block, 12);
+			assert_eq!(Balances::free_balance(BOB), 30_000 - rent - rent_2);
+
+			// Second call on same block should have no effect on rent
+			assert_ok!(Contract::call(Origin::signed(ALICE), BOB, 0, 100_000, call::null()));
+
+			let bob_contract = super::ContractInfoOf::<Test>::get(BOB).unwrap().get_alive().unwrap();
+			assert_eq!(bob_contract.rent_allowance, 1_000 - rent - rent_2);
+			assert_eq!(bob_contract.deduct_block, 12);
+			assert_eq!(Balances::free_balance(BOB), 30_000 - rent - rent_2);
 		}
 	);
 }