pallet_broker: Let start_sales calculate and request the correct core count

substrate/frame/broker/src/dispatchable_impls.rs

@@ -70,8 +70,16 @@ impl<T: Config> Pallet<T> {
 		Ok(())
 	}
 
-	pub(crate) fn do_start_sales(price: BalanceOf<T>, core_count: CoreIndex) -> DispatchResult {
+	pub(crate) fn do_start_sales(price: BalanceOf<T>, extra_cores: CoreIndex) -> DispatchResult {
 		let config = Configuration::<T>::get().ok_or(Error::<T>::Uninitialized)?;
+
+		// Determine the core count
+		let core_count = Leases::<T>::decode_len().unwrap_or(0) as CoreIndex +
+			Reservations::<T>::decode_len().unwrap_or(0) as CoreIndex +
+			extra_cores;
+
+		Self::do_request_core_count(core_count)?;
+
 		let commit_timeslice = Self::latest_timeslice_ready_to_commit(&config);
 		let status = StatusRecord {
 			core_count,

substrate/frame/broker/src/lib.rs

@@ -559,27 +559,20 @@ pub mod pallet {
 		///
 		/// - `origin`: Must be Root or pass `AdminOrigin`.
 		/// - `initial_price`: The price of Bulk Coretime in the first sale.
-		/// - `total_core_count`: This is the total number of cores the relay chain should have
-		/// after the sale concludes.
+		/// - `extra_cores`: Number of extra cores that should be requested on top of the cores
+		///   required for `Reservations` and `Leases`.
 		///
-		/// NOTE: This function does not actually request that new core count from the relay chain.
-		/// You need to make sure to call `request_core_count` afterwards to bring the relay chain
-		/// in sync.
-		///
-		/// When to call the function depends on the new core count. If it is larger than what it
-		/// was before, you can call it immediately or even before `start_sales` as non allocated
-		/// cores will just be `Idle`. If you are actually reducing the number of cores, you should
-		/// call `request_core_count`, right before the next sale, to avoid shutting down tasks too
-		/// early.
+		/// This will call [`Self::request_core_count`] internally to set the correct core count on
+		/// the relay chain.
 		#[pallet::call_index(4)]
-		#[pallet::weight(T::WeightInfo::start_sales((*total_core_count).into()))]
+		#[pallet::weight(T::WeightInfo::start_sales(T::MaxLeasedCores::get() + T::MaxReservedCores::get()))]
 		pub fn start_sales(
 			origin: OriginFor<T>,
 			initial_price: BalanceOf<T>,
-			total_core_count: CoreIndex,
+			extra_cores: CoreIndex,
 		) -> DispatchResultWithPostInfo {
 			T::AdminOrigin::ensure_origin_or_root(origin)?;
-			Self::do_start_sales(initial_price, total_core_count)?;
+			Self::do_start_sales(initial_price, extra_cores)?;
 			Ok(Pays::No.into())
 		}
 

substrate/frame/broker/src/tests.rs

@@ -1408,3 +1408,23 @@ fn renewal_works_leases_ended_before_start_sales() {
 		);
 	});
 }
+
+#[test]
+fn start_sales_sets_correct_core_count() {
+	TestExt::new().endow(1, 1000).execute_with(|| {
+		advance_to(1);
+
+		Broker::do_set_lease(1, 100).unwrap();
+		Broker::do_set_lease(2, 100).unwrap();
+		Broker::do_set_lease(3, 100).unwrap();
+		Broker::do_reserve(Schedule::truncate_from(vec![ScheduleItem {
+			assignment: Pool,
+			mask: CoreMask::complete(),
+		}]))
+		.unwrap();
+
+		Broker::do_start_sales(5, 5).unwrap();
+
+		System::assert_has_event(Event::<Test>::CoreCountRequested { core_count: 9 }.into());
+	})
+}