Manual Para Lock (#5451)

* remove para lock check for now

* fmt

* manual para lock

* expose schedule_code_upgrade and set_current_head

* extrinsics and benchmarks

* use zero

* add weights

* fix variable name

* add and fix comments

* fix weights

* add back default lock

Co-authored-by: parity-processbot <>

polkadot/runtime/parachains/src/paras/mod.rs

@@ -118,7 +118,7 @@ use primitives::v2::{
 use scale_info::TypeInfo;
 use sp_core::RuntimeDebug;
 use sp_runtime::{
-	traits::{AppVerify, One},
+	traits::{AppVerify, One, Saturating},
 	DispatchResult, SaturatedConversion,
 };
 use sp_std::{cmp, mem, prelude::*};
@@ -535,6 +535,8 @@ pub mod pallet {
 		/// The PVF pre-checking statement cannot be included since the PVF pre-checking mechanism
 		/// is disabled.
 		PvfCheckDisabled,
+		/// Parachain cannot currently schedule a code upgrade.
+		CannotUpgradeCode,
 	}
 
 	/// All currently active PVF pre-checking votes.
@@ -752,8 +754,7 @@ pub mod pallet {
 			new_head: HeadData,
 		) -> DispatchResult {
 			ensure_root(origin)?;
-			<Self as Store>::Heads::insert(&para, new_head);
-			Self::deposit_event(Event::CurrentHeadUpdated(para));
+			Self::set_current_head(para, new_head);
 			Ok(())
 		}
 
@@ -1050,6 +1051,31 @@ const INVALID_TX_DOUBLE_VOTE: u8 = 3;
 const INVALID_TX_PVF_CHECK_DISABLED: u8 = 4;
 
 impl<T: Config> Pallet<T> {
+	/// This is a call to schedule code upgrades for parachains which is safe to be called
+	/// outside of this module. That means this function does all checks necessary to ensure
+	/// that some external code is allowed to trigger a code upgrade. We do not do auth checks,
+	/// that should be handled by whomever calls this function.
+	pub(crate) fn schedule_code_upgrade_external(
+		id: ParaId,
+		new_code: ValidationCode,
+	) -> DispatchResult {
+		// Check that we can schedule an upgrade at all.
+		ensure!(Self::can_upgrade_validation_code(id), Error::<T>::CannotUpgradeCode);
+		let config = configuration::Pallet::<T>::config();
+		let current_block = frame_system::Pallet::<T>::block_number();
+		// Schedule the upgrade with a delay just like if a parachain triggered the upgrade.
+		let upgrade_block = current_block.saturating_add(config.validation_upgrade_delay);
+		Self::schedule_code_upgrade(id, new_code, upgrade_block, &config);
+		Self::deposit_event(Event::CodeUpgradeScheduled(id));
+		Ok(())
+	}
+
+	/// Set the current head of a parachain.
+	pub(crate) fn set_current_head(para: ParaId, new_head: HeadData) {
+		<Self as Store>::Heads::insert(&para, new_head);
+		Self::deposit_event(Event::CurrentHeadUpdated(para));
+	}
+
 	/// Called by the initializer to initialize the paras pallet.
 	pub(crate) fn initializer_initialize(now: T::BlockNumber) -> Weight {
 		let weight = Self::prune_old_code(now);