contracts: Multi block migrations (#14045)

* Frame Add translate_next

This works similarly to to `translate` but only translate a single entry.
This function will be useful in the context of multi-block migration.

* Move to lazy migration

* Updates

* simplify MockMigration

* wip

* wip

* add bench

* add bench

* fmt

* fix bench

* add .

* ".git/.scripts/commands/bench/bench.sh" pallet dev pallet_contracts

* Apply suggestions from code review

Co-authored-by: Alexander Theißen <alex.theissen@me.com>

* Scalfold v10 / v11 fix tests

* PR comment

* tweak pub use

* wip

* wip

* wip

* misc merge master

* misc merge master

* wip

* rm tmp stuff

* wip

* wip

* wip

* wip

* wip

* fixes

* add state

* wip

* wip

* wip

* wip

* wip

* wip

* wip

* wip

* wip

* wip

* wip

* wip

* wip

* wip

* fix

* fixed compilation

* clean up logs

* wip

* Revert "Frame Add translate_next"

This reverts commit 10318fc95c42b1f7f25efeb35e6d947ea02bed88.

* Fix v10 logic

* Apply suggestions from code review

Co-authored-by: Alexander Theißen <alex.theissen@me.com>

* wip

* fixes

* exercise del_queue

* bump sample size

* fmt

* wip

* blank line

* fix lint

* fix rustdoc job lint

* PR comment do not use dangerous into()

* Ad macros for updating mod visibility

* Add doc

* Add max_weight to integrity_test

* fix compilation

* Add no migration tests

* ".git/.scripts/commands/bench/bench.sh" pallet dev pallet_contracts

* fix clippy

* PR review

* Update frame/contracts/src/lib.rs

Co-authored-by: Sasha Gryaznov <hi@agryaznov.com>

* Fix master merge

* fix merge 2

* fix tryruntime

* fix lint

---------

Co-authored-by: Alexander Theißen <alex.theissen@me.com>
Co-authored-by: command-bot <>
Co-authored-by: Sasha Gryaznov <hi@agryaznov.com>

substrate/frame/contracts/primitives/src/lib.rs

@@ -105,6 +105,8 @@ pub enum ContractAccessError {
 	DoesntExist,
 	/// Storage key cannot be decoded from the provided input data.
 	KeyDecodingFailed,
+	/// Storage is migrating. Try again later.
+	MigrationInProgress,
 }
 
 bitflags! {

substrate/frame/contracts/src/benchmarking/mod.rs

@@ -21,7 +21,6 @@
 
 mod code;
 mod sandbox;
-
 use self::{
 	code::{
 		body::{self, DynInstr::*},
@@ -31,12 +30,13 @@ use self::{
 };
 use crate::{
 	exec::{AccountIdOf, Key},
+	migration::{v10, v11, v9, Migrate},
 	wasm::CallFlags,
 	Pallet as Contracts, *,
 };
 use codec::{Encode, MaxEncodedLen};
 use frame_benchmarking::v1::{account, benchmarks, whitelisted_caller};
-use frame_support::weights::Weight;
+use frame_support::{pallet_prelude::StorageVersion, weights::Weight};
 use frame_system::RawOrigin;
 use sp_runtime::{
 	traits::{Bounded, Hash},
@@ -234,6 +234,94 @@ benchmarks! {
 		Contracts::<T>::reinstrument_module(&mut module, &schedule)?;
 	}
 
+	// This benchmarks the v9 migration step. (update codeStorage)
+	#[pov_mode = Measured]
+	v9_migration_step {
+		let c in 0 .. Perbill::from_percent(49).mul_ceil(T::MaxCodeLen::get());
+		v9::store_old_dummy_code::<T>(c as usize);
+		let mut m = v9::Migration::<T>::default();
+	}: {
+		m.step();
+	}
+
+	// This benchmarks the v10 migration step. (use dedicated deposit_account)
+	#[pov_mode = Measured]
+	v10_migration_step {
+		let contract = <Contract<T>>::with_caller(
+			whitelisted_caller(), WasmModule::dummy(), vec![],
+		)?;
+
+		v10::store_old_contrat_info::<T>(contract.account_id.clone(), contract.info()?);
+		let mut m = v10::Migration::<T>::default();
+	}: {
+		m.step();
+	}
+
+	// This benchmarks the v11 migration step.
+	#[pov_mode = Measured]
+	v11_migration_step {
+		let k in 0 .. 1024;
+		v11::fill_old_queue::<T>(k as usize);
+		let mut m = v11::Migration::<T>::default();
+	}: {
+		m.step();
+	}
+
+	// This benchmarks the weight of executing Migration::migrate to execute a noop migration.
+	#[pov_mode = Measured]
+	migration_noop {
+		assert_eq!(StorageVersion::get::<Pallet<T>>(), 2);
+	}:  {
+		Migration::<T>::migrate(Weight::MAX)
+	} verify {
+		assert_eq!(StorageVersion::get::<Pallet<T>>(), 2);
+	}
+
+	// This benchmarks the weight of executing Migration::migrate when there are no migration in progress.
+	#[pov_mode = Measured]
+	migrate {
+		StorageVersion::new(0).put::<Pallet<T>>();
+		<Migration::<T> as frame_support::traits::OnRuntimeUpgrade>::on_runtime_upgrade();
+		let origin: RawOrigin<<T as frame_system::Config>::AccountId> = RawOrigin::Signed(whitelisted_caller());
+	}: {
+		<Contracts<T>>::migrate(origin.into(), Weight::MAX).unwrap()
+	} verify {
+		assert_eq!(StorageVersion::get::<Pallet<T>>(), 1);
+	}
+
+	// This benchmarks the weight of running on_runtime_upgrade when there are no migration in progress.
+	#[pov_mode = Measured]
+	on_runtime_upgrade_noop {
+		assert_eq!(StorageVersion::get::<Pallet<T>>(), 2);
+	}:  {
+		<Migration::<T> as frame_support::traits::OnRuntimeUpgrade>::on_runtime_upgrade()
+	} verify {
+		assert!(MigrationInProgress::<T>::get().is_none());
+	}
+
+	// This benchmarks the weight of running on_runtime_upgrade when there is a migration in progress.
+	#[pov_mode = Measured]
+	on_runtime_upgrade_in_progress {
+		StorageVersion::new(0).put::<Pallet<T>>();
+		let v = vec![42u8].try_into().ok();
+		MigrationInProgress::<T>::set(v.clone());
+	}:  {
+		<Migration::<T> as frame_support::traits::OnRuntimeUpgrade>::on_runtime_upgrade()
+	} verify {
+		assert!(MigrationInProgress::<T>::get().is_some());
+		assert_eq!(MigrationInProgress::<T>::get(), v);
+	}
+
+	// This benchmarks the weight of running on_runtime_upgrade when there is a migration to process.
+	#[pov_mode = Measured]
+	on_runtime_upgrade {
+		StorageVersion::new(0).put::<Pallet<T>>();
+	}:  {
+		<Migration::<T> as frame_support::traits::OnRuntimeUpgrade>::on_runtime_upgrade()
+	} verify {
+		assert!(MigrationInProgress::<T>::get().is_some());
+	}
+
 	// This benchmarks the overhead of loading a code of size `c` byte from storage and into
 	// the sandbox. This does **not** include the actual execution for which the gas meter
 	// is responsible. This is achieved by generating all code to the `deploy` function

substrate/frame/contracts/src/lib.rs

@@ -107,7 +107,10 @@ use crate::{
 use codec::{Codec, Decode, Encode, HasCompact};
 use environmental::*;
 use frame_support::{
-	dispatch::{DispatchError, Dispatchable, GetDispatchInfo, Pays, PostDispatchInfo, RawOrigin},
+	dispatch::{
+		DispatchError, Dispatchable, GetDispatchInfo, Pays, PostDispatchInfo, RawOrigin,
+		WithPostDispatchInfo,
+	},
 	ensure,
 	error::BadOrigin,
 	traits::{
@@ -120,18 +123,18 @@ use frame_support::{
 use frame_system::{ensure_signed, pallet_prelude::OriginFor, EventRecord, Pallet as System};
 use pallet_contracts_primitives::{
 	Code, CodeUploadResult, CodeUploadReturnValue, ContractAccessError, ContractExecResult,
-	ContractInstantiateResult, ExecReturnValue, GetStorageResult, InstantiateReturnValue,
+	ContractInstantiateResult, ContractResult, ExecReturnValue, GetStorageResult,
-	StorageDeposit,
+	InstantiateReturnValue, StorageDeposit,
 };
 use scale_info::TypeInfo;
 use smallvec::Array;
-use sp_runtime::traits::{Convert, Hash, Saturating, StaticLookup};
+use sp_runtime::traits::{Convert, Hash, Saturating, StaticLookup, Zero};
 use sp_std::{fmt::Debug, marker::PhantomData, prelude::*};
 
 pub use crate::{
 	address::{AddressGenerator, DefaultAddressGenerator},
 	exec::Frame,
-	migration::Migration,
+	migration::{MigrateSequence, Migration, NoopMigration},
 	pallet::*,
 	schedule::{HostFnWeights, InstructionWeights, Limits, Schedule},
 	wasm::Determinism,
@@ -179,7 +182,12 @@ pub mod pallet {
 	use frame_system::pallet_prelude::*;
 
 	/// The current storage version.
-	const STORAGE_VERSION: StorageVersion = StorageVersion::new(9);
+	#[cfg(not(any(test, feature = "runtime-benchmarks")))]
+	const STORAGE_VERSION: StorageVersion = StorageVersion::new(11);
+
+	/// Hard coded storage version for running tests that depend on the current storage version.
+	#[cfg(any(test, feature = "runtime-benchmarks"))]
+	const STORAGE_VERSION: StorageVersion = StorageVersion::new(2);
 
 	#[pallet::pallet]
 	#[pallet::storage_version(STORAGE_VERSION)]
@@ -316,11 +324,22 @@ pub mod pallet {
 	#[pallet::hooks]
 	impl<T: Config> Hooks<BlockNumberFor<T>> for Pallet<T> {
 		fn on_idle(_block: T::BlockNumber, remaining_weight: Weight) -> Weight {
+			use migration::MigrateResult::*;
+
+			let (result, weight) = Migration::<T>::migrate(remaining_weight);
+			let remaining_weight = remaining_weight.saturating_sub(weight);
+
+			if !matches!(result, Completed | NoMigrationInProgress) {
+				return weight
+			}
+
 			ContractInfo::<T>::process_deletion_queue_batch(remaining_weight)
 				.saturating_add(T::WeightInfo::on_process_deletion_queue_batch())
 		}
 
 		fn integrity_test() {
+			Migration::<T>::integrity_test();
+
 			// Total runtime memory limit
 			let max_runtime_mem: u32 = T::Schedule::get().limits.runtime_memory;
 			// Memory limits for a single contract:
@@ -499,6 +518,7 @@ pub mod pallet {
 			storage_deposit_limit: Option<<BalanceOf<T> as codec::HasCompact>::Type>,
 			determinism: Determinism,
 		) -> DispatchResult {
+			Migration::<T>::ensure_migrated()?;
 			let origin = ensure_signed(origin)?;
 			Self::bare_upload_code(origin, code, storage_deposit_limit.map(Into::into), determinism)
 				.map(|_| ())
@@ -514,6 +534,7 @@ pub mod pallet {
 			origin: OriginFor<T>,
 			code_hash: CodeHash<T>,
 		) -> DispatchResultWithPostInfo {
+			Migration::<T>::ensure_migrated()?;
 			let origin = ensure_signed(origin)?;
 			<PrefabWasmModule<T>>::remove(&origin, code_hash)?;
 			// we waive the fee because removing unused code is beneficial
@@ -537,6 +558,7 @@ pub mod pallet {
 			dest: AccountIdLookupOf<T>,
 			code_hash: CodeHash<T>,
 		) -> DispatchResult {
+			Migration::<T>::ensure_migrated()?;
 			ensure_root(origin)?;
 			let dest = T::Lookup::lookup(dest)?;
 			<ContractInfoOf<T>>::try_mutate(&dest, |contract| {
@@ -586,6 +608,7 @@ pub mod pallet {
 			storage_deposit_limit: Option<<BalanceOf<T> as codec::HasCompact>::Type>,
 			data: Vec<u8>,
 		) -> DispatchResultWithPostInfo {
+			Migration::<T>::ensure_migrated()?;
 			let common = CommonInput {
 				origin: Origin::from_runtime_origin(origin)?,
 				value,
@@ -645,6 +668,7 @@ pub mod pallet {
 			data: Vec<u8>,
 			salt: Vec<u8>,
 		) -> DispatchResultWithPostInfo {
+			Migration::<T>::ensure_migrated()?;
 			let code_len = code.len() as u32;
 			let data_len = data.len() as u32;
 			let salt_len = salt.len() as u32;
@@ -687,6 +711,7 @@ pub mod pallet {
 			data: Vec<u8>,
 			salt: Vec<u8>,
 		) -> DispatchResultWithPostInfo {
+			Migration::<T>::ensure_migrated()?;
 			let data_len = data.len() as u32;
 			let salt_len = salt.len() as u32;
 			let common = CommonInput {
@@ -709,6 +734,33 @@ pub mod pallet {
 				T::WeightInfo::instantiate(data_len, salt_len),
 			)
 		}
+
+		/// When a migration is in progress, this dispatchable can be used to run migration steps.
+		/// Calls that contribute to advancing the migration have their fees waived, as it's helpful
+		/// for the chain. Note that while the migration is in progress, the pallet will also
+		/// leverage the `on_idle` hooks to run migration steps.
+		#[pallet::call_index(9)]
+		#[pallet::weight(T::WeightInfo::migrate().saturating_add(*weight_limit))]
+		pub fn migrate(origin: OriginFor<T>, weight_limit: Weight) -> DispatchResultWithPostInfo {
+			use migration::MigrateResult::*;
+			ensure_signed(origin)?;
+
+			let weight_limit = weight_limit.saturating_add(T::WeightInfo::migrate());
+			let (result, weight) = Migration::<T>::migrate(weight_limit);
+
+			match result {
+				Completed =>
+					Ok(PostDispatchInfo { actual_weight: Some(weight), pays_fee: Pays::No }),
+				InProgress { steps_done, .. } if steps_done > 0 =>
+					Ok(PostDispatchInfo { actual_weight: Some(weight), pays_fee: Pays::No }),
+				InProgress { .. } =>
+					Ok(PostDispatchInfo { actual_weight: Some(weight), pays_fee: Pays::Yes }),
+				NoMigrationInProgress | NoMigrationPerformed => {
+					let err: DispatchError = <Error<T>>::NoMigrationPerformed.into();
+					Err(err.with_weight(T::WeightInfo::migrate()))
+				},
+			}
+		}
 	}
 
 	#[pallet::event]
@@ -861,6 +913,10 @@ pub mod pallet {
 		CodeRejected,
 		/// An indetermistic code was used in a context where this is not permitted.
 		Indeterministic,
+		/// A pending migration needs to complete before the extrinsic can be called.
+		MigrationInProgress,
+		/// Migrate dispatch call was attempted but no migration was performed.
+		NoMigrationPerformed,
 	}
 
 	/// A mapping from an original code hash to the original code, untouched by instrumentation.
@@ -920,6 +976,10 @@ pub mod pallet {
 	#[pallet::storage]
 	pub(crate) type DeletionQueueCounter<T: Config> =
 		StorageValue<_, DeletionQueueManager<T>, ValueQuery>;
+
+	#[pallet::storage]
+	pub(crate) type MigrationInProgress<T: Config> =
+		StorageValue<_, migration::Cursor, OptionQuery>;
 }
 
 /// The type of origins supported by the contracts pallet.
@@ -1210,6 +1270,21 @@ impl<T: Config> Invokable<T> for InstantiateInput<T> {
 	}
 }
 
+macro_rules! ensure_no_migration_in_progress {
+	() => {
+		if Migration::<T>::in_progress() {
+			return ContractResult {
+				gas_consumed: Zero::zero(),
+				gas_required: Zero::zero(),
+				storage_deposit: Default::default(),
+				debug_message: Vec::new(),
+				result: Err(Error::<T>::MigrationInProgress.into()),
+				events: None,
+			}
+		}
+	};
+}
+
 impl<T: Config> Pallet<T> {
 	/// Perform a call to a specified contract.
 	///
@@ -1234,6 +1309,8 @@ impl<T: Config> Pallet<T> {
 		collect_events: CollectEvents,
 		determinism: Determinism,
 	) -> ContractExecResult<BalanceOf<T>, EventRecordOf<T>> {
+		ensure_no_migration_in_progress!();
+
 		let mut debug_message = if matches!(debug, DebugInfo::UnsafeDebug) {
 			Some(DebugBufferVec::<T>::default())
 		} else {
@@ -1290,6 +1367,8 @@ impl<T: Config> Pallet<T> {
 		debug: DebugInfo,
 		collect_events: CollectEvents,
 	) -> ContractInstantiateResult<T::AccountId, BalanceOf<T>, EventRecordOf<T>> {
+		ensure_no_migration_in_progress!();
+
 		let mut debug_message = if debug == DebugInfo::UnsafeDebug {
 			Some(DebugBufferVec::<T>::default())
 		} else {
@@ -1333,6 +1412,7 @@ impl<T: Config> Pallet<T> {
 		storage_deposit_limit: Option<BalanceOf<T>>,
 		determinism: Determinism,
 	) -> CodeUploadResult<CodeHash<T>, BalanceOf<T>> {
+		Migration::<T>::ensure_migrated()?;
 		let schedule = T::Schedule::get();
 		let module = PrefabWasmModule::from_code(
 			code,
@@ -1353,6 +1433,9 @@ impl<T: Config> Pallet<T> {
 
 	/// Query storage of a specified contract under a specified key.
 	pub fn get_storage(address: T::AccountId, key: Vec<u8>) -> GetStorageResult {
+		if Migration::<T>::in_progress() {
+			return Err(ContractAccessError::MigrationInProgress)
+		}
 		let contract_info =
 			ContractInfoOf::<T>::get(&address).ok_or(ContractAccessError::DoesntExist)?;
 

substrate/frame/contracts/src/migration.rs

@@ -15,462 +15,589 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use crate::{BalanceOf, CodeHash, Config, Pallet, TrieId, Weight};
+//! Migration framework for pallets.
-use codec::{Decode, Encode};
+
+/// Macro to include all migration modules.
+/// We only want to make these modules public when `runtime-benchmarks` is
+/// enabled, so we can access migration code in benchmarks.
+macro_rules! use_modules {
+    ($($module:ident),*) => {
+        $(
+            #[cfg(feature = "runtime-benchmarks")]
+            pub mod $module;
+            #[cfg(not(feature = "runtime-benchmarks"))]
+            mod $module;
+        )*
+    };
+}
+
+use_modules!(v9, v10, v11);
+use crate::{weights::WeightInfo, Config, Error, MigrationInProgress, Pallet, Weight, LOG_TARGET};
+use codec::{Codec, Decode};
 use frame_support::{
 	codec,
 	pallet_prelude::*,
-	storage::migration,
+	traits::{ConstU32, OnRuntimeUpgrade},
-	storage_alias,
-	traits::{Get, OnRuntimeUpgrade},
-	Identity, Twox64Concat,
 };
-use sp_runtime::traits::Saturating;
+use sp_std::marker::PhantomData;
-use sp_std::{marker::PhantomData, prelude::*};
+
+#[cfg(feature = "try-runtime")]
+use sp_std::prelude::*;
 
 #[cfg(feature = "try-runtime")]
 use sp_runtime::TryRuntimeError;
 
+const PROOF_ENCODE: &str = "Tuple::max_encoded_len() < Cursor::max_encoded_len()` is verified in `Self::integrity_test()`; qed";
+const PROOF_DECODE: &str =
+	"We encode to the same type in this trait only. No other code touches this item; qed";
+
+fn invalid_version(version: StorageVersion) -> ! {
+	panic!("Required migration {version:?} not supported by this runtime. This is a bug.");
+}
+
+/// The cursor used to store the state of the current migration step.
+pub type Cursor = BoundedVec<u8, ConstU32<1024>>;
+
+// In benchmark and tests we use noop migrations, to test and bench the migration framework itself.
+#[cfg(not(any(feature = "runtime-benchmarks", test)))]
+type Migrations<T> = (v9::Migration<T>, v10::Migration<T>, v11::Migration<T>);
+
+/// IsFinished describes whether a migration is finished or not.
+pub enum IsFinished {
+	Yes,
+	No,
+}
+
+/// A trait that allows to migrate storage from one version to another.
+///
+/// The migration is done in steps. The migration is finished when
+/// `step()` returns `IsFinished::Yes`.
+pub trait Migrate: Codec + MaxEncodedLen + Default {
+	/// Returns the version of the migration.
+	const VERSION: u16;
+
+	/// Returns the maximum weight that can be consumed in a single step.
+	fn max_step_weight() -> Weight;
+
+	/// Process one step of the migration.
+	///
+	/// Returns whether the migration is finished and the weight consumed.
+	fn step(&mut self) -> (IsFinished, Weight);
+
+	/// Verify that the migration step fits into `Cursor`, and that `max_step_weight` is not greater
+	/// than `max_block_weight`.
+	fn integrity_test(max_block_weight: Weight) {
+		if Self::max_step_weight().any_gt(max_block_weight) {
+			panic!(
+				"Invalid max_step_weight for Migration {}. Value should be lower than {}",
+				Self::VERSION,
+				max_block_weight
+			);
+		}
+
+		let len = <Self as MaxEncodedLen>::max_encoded_len();
+		let max = Cursor::bound();
+		if len > max {
+			panic!(
+				"Migration {} has size {} which is bigger than the maximum of {}",
+				Self::VERSION,
+				len,
+				max,
+			);
+		}
+	}
+
+	/// Execute some pre-checks prior to running the first step of this migration.
+	#[cfg(feature = "try-runtime")]
+	fn pre_upgrade_step() -> Result<Vec<u8>, TryRuntimeError> {
+		Ok(Vec::new())
+	}
+
+	/// Execute some post-checks after running the last step of this migration.
+	#[cfg(feature = "try-runtime")]
+	fn post_upgrade_step(_state: Vec<u8>) -> Result<(), TryRuntimeError> {
+		Ok(())
+	}
+}
+
+/// A noop migration that can be used when there is no migration to be done for a given version.
+#[doc(hidden)]
+#[derive(frame_support::DefaultNoBound, Encode, Decode, MaxEncodedLen)]
+pub struct NoopMigration<const N: u16>;
+
+impl<const N: u16> Migrate for NoopMigration<N> {
+	const VERSION: u16 = N;
+	fn max_step_weight() -> Weight {
+		Weight::zero()
+	}
+	fn step(&mut self) -> (IsFinished, Weight) {
+		log::debug!(target: LOG_TARGET, "Noop migration for version {}", N);
+		(IsFinished::Yes, Weight::zero())
+	}
+}
+
+mod private {
+	use crate::migration::Migrate;
+	pub trait Sealed {}
+	#[impl_trait_for_tuples::impl_for_tuples(10)]
+	#[tuple_types_custom_trait_bound(Migrate)]
+	impl Sealed for Tuple {}
+}
+
+/// Defines a sequence of migrations.
+///
+/// The sequence must be defined by a tuple of migrations, each of which must implement the
+/// `Migrate` trait. Migrations must be ordered by their versions with no gaps.
+pub trait MigrateSequence: private::Sealed {
+	/// Returns the range of versions that this migration can handle.
+	/// Migrations must be ordered by their versions with no gaps.
+	/// The following code will fail to compile:
+	///
+	/// The following code will fail to compile:
+	/// ```compile_fail
+	///     # use pallet_contracts::{NoopMigration, MigrateSequence};
+	/// 	let _ = <(NoopMigration<1>, NoopMigration<3>)>::VERSION_RANGE;
+	/// ```
+	/// The following code will compile:
+	/// ```
+	///     # use pallet_contracts::{NoopMigration, MigrateSequence};
+	/// 	let _ = <(NoopMigration<1>, NoopMigration<2>)>::VERSION_RANGE;
+	/// ```
+	const VERSION_RANGE: (u16, u16);
+
+	/// Returns the default cursor for the given version.
+	fn new(version: StorageVersion) -> Cursor;
+
+	#[cfg(feature = "try-runtime")]
+	fn pre_upgrade_step(_version: StorageVersion) -> Result<Vec<u8>, TryRuntimeError> {
+		Ok(Vec::new())
+	}
+
+	#[cfg(feature = "try-runtime")]
+	fn post_upgrade_step(_version: StorageVersion, _state: Vec<u8>) -> Result<(), TryRuntimeError> {
+		Ok(())
+	}
+
+	/// Execute the migration step until the weight limit is reached.
+	fn steps(version: StorageVersion, cursor: &[u8], weight_left: &mut Weight) -> StepResult;
+
+	/// Verify that the migration step fits into `Cursor`, and that `max_step_weight` is not greater
+	/// than `max_block_weight`.
+	fn integrity_test(max_block_weight: Weight);
+
+	/// Returns whether migrating from `in_storage` to `target` is supported.
+	///
+	/// A migration is supported if (in_storage + 1, target) is contained by `VERSION_RANGE`.
+	fn is_upgrade_supported(in_storage: StorageVersion, target: StorageVersion) -> bool {
+		if in_storage == target {
+			return true
+		}
+		if in_storage > target {
+			return false
+		}
+
+		let (low, high) = Self::VERSION_RANGE;
+		let Some(first_supported) = low.checked_sub(1) else {
+			return false
+		};
+
+		in_storage >= first_supported && target == high
+	}
+}
+
 /// Performs all necessary migrations based on `StorageVersion`.
-pub struct Migration<T: Config>(PhantomData<T>);
+#[cfg(not(any(feature = "runtime-benchmarks", test)))]
-impl<T: Config> OnRuntimeUpgrade for Migration<T> {
+pub struct Migration<T: Config, M: MigrateSequence = Migrations<T>>(PhantomData<(T, M)>);
-	fn on_runtime_upgrade() -> Weight {
+
-		let version = <Pallet<T>>::on_chain_storage_version();
+/// Custom migration for running runtime-benchmarks and tests.
+#[cfg(any(feature = "runtime-benchmarks", test))]
+pub struct Migration<T: Config, M: MigrateSequence = (NoopMigration<1>, NoopMigration<2>)>(
+	PhantomData<(T, M)>,
+);
+
+#[cfg(feature = "try-runtime")]
+impl<T: Config, M: MigrateSequence> Migration<T, M> {
+	fn run_all_steps() -> Result<(), TryRuntimeError> {
 		let mut weight = Weight::zero();
-
+		let name = <Pallet<T>>::name();
-		if version < 4 {
+		loop {
-			v4::migrate::<T>(&mut weight);
+			let in_progress_version = <Pallet<T>>::on_chain_storage_version() + 1;
+			let state = M::pre_upgrade_step(in_progress_version)?;
+			let (status, w) = Self::migrate(Weight::MAX);
+			weight.saturating_accrue(w);
+			log::info!(
+				target: LOG_TARGET,
+				"{name}: Migration step {:?} weight = {}",
+				in_progress_version,
+				weight
+			);
+			M::post_upgrade_step(in_progress_version, state)?;
+			if matches!(status, MigrateResult::Completed) {
+				break
+			}
 		}
 
-		if version < 5 {
+		let name = <Pallet<T>>::name();
-			v5::migrate::<T>(&mut weight);
+		log::info!(target: LOG_TARGET, "{name}: Migration steps weight = {}", weight);
+		Ok(())
+	}
+}
+
+impl<T: Config, M: MigrateSequence> OnRuntimeUpgrade for Migration<T, M> {
+	fn on_runtime_upgrade() -> Weight {
+		let name = <Pallet<T>>::name();
+		let latest_version = <Pallet<T>>::current_storage_version();
+		let storage_version = <Pallet<T>>::on_chain_storage_version();
+
+		if storage_version == latest_version {
+			log::warn!(
+				target: LOG_TARGET,
+				"{name}: No Migration performed storage_version = latest_version = {:?}",
+				&storage_version
+			);
+			return T::WeightInfo::on_runtime_upgrade_noop()
 		}
 
-		if version < 6 {
+		// In case a migration is already in progress we create the next migration
-			v6::migrate::<T>(&mut weight);
+		// (if any) right when the current one finishes.
+		if Self::in_progress() {
+			log::warn!(
+				target: LOG_TARGET,
+				"{name}: Migration already in progress {:?}",
+				&storage_version
+			);
+			return T::WeightInfo::on_runtime_upgrade_in_progress()
 		}
 
-		if version < 7 {
+		log::info!(
-			v7::migrate::<T>(&mut weight);
+			target: LOG_TARGET,
-		}
+			"{name}: Upgrading storage from {storage_version:?} to {latest_version:?}.",
+		);
 
-		if version < 8 {
+		let cursor = M::new(storage_version + 1);
-			v8::migrate::<T>(&mut weight);
+		MigrationInProgress::<T>::set(Some(cursor));
-		}
 
-		if version < 9 {
+		#[cfg(feature = "try-runtime")]
-			v9::migrate::<T>(&mut weight);
+		Self::run_all_steps().unwrap();
-		}
 
-		StorageVersion::new(9).put::<Pallet<T>>();
+		return T::WeightInfo::on_runtime_upgrade()
-		weight.saturating_accrue(T::DbWeight::get().writes(1));
-
-		weight
 	}
 
 	#[cfg(feature = "try-runtime")]
 	fn pre_upgrade() -> Result<Vec<u8>, TryRuntimeError> {
-		let version = <Pallet<T>>::on_chain_storage_version();
+		// We can't really do much here as our migrations do not happen during the runtime upgrade.
+		// Instead, we call the migrations `pre_upgrade` and `post_upgrade` hooks when we iterate
+		// over our migrations.
+		let storage_version = <Pallet<T>>::on_chain_storage_version();
+		let target_version = <Pallet<T>>::current_storage_version();
 
-		if version == 7 {
+		log::debug!(
-			v8::pre_upgrade::<T>()?;
+			target: LOG_TARGET,
+			"{}: Range supported {:?}, range requested {:?}",
+			<Pallet<T>>::name(),
+			M::VERSION_RANGE,
+			(storage_version, target_version)
+		);
+
+		ensure!(M::is_upgrade_supported(storage_version, target_version), "Unsupported upgrade");
+		Ok(Default::default())
+	}
+}
+
+/// The result of running the migration.
+#[derive(Debug, PartialEq)]
+pub enum MigrateResult {
+	/// No migration was performed
+	NoMigrationPerformed,
+	/// No migration currently in progress
+	NoMigrationInProgress,
+	/// A migration is in progress
+	InProgress { steps_done: u32 },
+	/// All migrations are completed
+	Completed,
+}
+
+/// The result of running a migration step.
+#[derive(Debug, PartialEq)]
+pub enum StepResult {
+	InProgress { cursor: Cursor, steps_done: u32 },
+	Completed { steps_done: u32 },
+}
+
+impl<T: Config, M: MigrateSequence> Migration<T, M> {
+	/// Verify that each migration's step of the MigrateSequence fits into `Cursor`.
+	pub(crate) fn integrity_test() {
+		let max_weight = <T as frame_system::Config>::BlockWeights::get().max_block;
+		M::integrity_test(max_weight)
+	}
+
+	/// Migrate
+	/// Return the weight used and whether or not a migration is in progress
+	pub(crate) fn migrate(weight_limit: Weight) -> (MigrateResult, Weight) {
+		let name = <Pallet<T>>::name();
+		let mut weight_left = weight_limit;
+
+		if weight_left.checked_reduce(T::WeightInfo::migrate()).is_none() {
+			return (MigrateResult::NoMigrationPerformed, Weight::zero())
 		}
 
-		Ok(version.encode())
+		MigrationInProgress::<T>::mutate_exists(|progress| {
-	}
+			let Some(cursor_before) = progress.as_mut() else {
+				return (MigrateResult::NoMigrationInProgress, T::WeightInfo::migration_noop())
+			};
 
-	#[cfg(feature = "try-runtime")]
+			// if a migration is running it is always upgrading to the next version
-	fn post_upgrade(state: Vec<u8>) -> Result<(), TryRuntimeError> {
+			let storage_version = <Pallet<T>>::on_chain_storage_version();
-		let version = Decode::decode(&mut state.as_ref()).map_err(|_| "Cannot decode version")?;
+			let in_progress_version = storage_version + 1;
-		post_checks::post_upgrade::<T>(version)
-	}
-}
 
-/// V4: `Schedule` is changed to be a config item rather than an in-storage value.
+			log::info!(
-mod v4 {
+				target: LOG_TARGET,
-	use super::*;
+				"{name}: Migrating from {:?} to {:?},",
+				storage_version,
+				in_progress_version,
+			);
 
-	pub fn migrate<T: Config>(weight: &mut Weight) {
+			let result =
-		#[allow(deprecated)]
+				match M::steps(in_progress_version, cursor_before.as_ref(), &mut weight_left) {
-		migration::remove_storage_prefix(<Pallet<T>>::name().as_bytes(), b"CurrentSchedule", b"");
+					StepResult::InProgress { cursor, steps_done } => {
-		weight.saturating_accrue(T::DbWeight::get().writes(1));
+						*progress = Some(cursor);
-	}
+						MigrateResult::InProgress { steps_done }
-}
+					},
+					StepResult::Completed { steps_done } => {
+						in_progress_version.put::<Pallet<T>>();
+						if <Pallet<T>>::current_storage_version() != in_progress_version {
+							log::info!(
+								target: LOG_TARGET,
+								"{name}: Next migration is {:?},",
+								in_progress_version + 1
+							);
+							*progress = Some(M::new(in_progress_version + 1));
+							MigrateResult::InProgress { steps_done }
+						} else {
+							log::info!(
+								target: LOG_TARGET,
+								"{name}: All migrations done. At version {:?},",
+								in_progress_version
+							);
+							*progress = None;
+							MigrateResult::Completed
+						}
+					},
+				};
 
-/// V5: State rent is removed which obsoletes some fields in `ContractInfo`.
+			(result, weight_limit.saturating_sub(weight_left))
-mod v5 {
-	use super::*;
-
-	type AliveContractInfo<T> =
-		RawAliveContractInfo<CodeHash<T>, BalanceOf<T>, <T as frame_system::Config>::BlockNumber>;
-	type TombstoneContractInfo<T> = RawTombstoneContractInfo<
-		<T as frame_system::Config>::Hash,
-		<T as frame_system::Config>::Hashing,
-	>;
-
-	#[derive(Decode)]
-	enum OldContractInfo<T: Config> {
-		Alive(AliveContractInfo<T>),
-		Tombstone(TombstoneContractInfo<T>),
-	}
-
-	#[derive(Decode)]
-	struct RawAliveContractInfo<CodeHash, Balance, BlockNumber> {
-		trie_id: TrieId,
-		_storage_size: u32,
-		_pair_count: u32,
-		code_hash: CodeHash,
-		_rent_allowance: Balance,
-		_rent_paid: Balance,
-		_deduct_block: BlockNumber,
-		_last_write: Option<BlockNumber>,
-		_reserved: Option<()>,
-	}
-
-	#[derive(Decode)]
-	struct RawTombstoneContractInfo<H, Hasher>(H, PhantomData<Hasher>);
-
-	#[derive(Decode)]
-	struct OldDeletedContract {
-		_pair_count: u32,
-		trie_id: TrieId,
-	}
-
-	pub type ContractInfo<T> = RawContractInfo<CodeHash<T>>;
-
-	#[derive(Encode, Decode)]
-	pub struct RawContractInfo<CodeHash> {
-		pub trie_id: TrieId,
-		pub code_hash: CodeHash,
-		pub _reserved: Option<()>,
-	}
-
-	#[derive(Encode, Decode)]
-	struct DeletedContract {
-		trie_id: TrieId,
-	}
-
-	#[storage_alias]
-	type ContractInfoOf<T: Config> = StorageMap<
-		Pallet<T>,
-		Twox64Concat,
-		<T as frame_system::Config>::AccountId,
-		ContractInfo<T>,
-	>;
-
-	#[storage_alias]
-	type DeletionQueue<T: Config> = StorageValue<Pallet<T>, Vec<DeletedContract>>;
-
-	pub fn migrate<T: Config>(weight: &mut Weight) {
-		<ContractInfoOf<T>>::translate(|_key, old: OldContractInfo<T>| {
-			weight.saturating_accrue(T::DbWeight::get().reads_writes(1, 1));
-			match old {
-				OldContractInfo::Alive(old) => Some(ContractInfo::<T> {
-					trie_id: old.trie_id,
-					code_hash: old.code_hash,
-					_reserved: old._reserved,
-				}),
-				OldContractInfo::Tombstone(_) => None,
-			}
-		});
-
-		DeletionQueue::<T>::translate(|old: Option<Vec<OldDeletedContract>>| {
-			weight.saturating_accrue(T::DbWeight::get().reads_writes(1, 1));
-			old.map(|old| old.into_iter().map(|o| DeletedContract { trie_id: o.trie_id }).collect())
 		})
-		.ok();
+	}
+
+	pub(crate) fn ensure_migrated() -> DispatchResult {
+		if Self::in_progress() {
+			Err(Error::<T>::MigrationInProgress.into())
+		} else {
+			Ok(())
+		}
+	}
+
+	pub(crate) fn in_progress() -> bool {
+		MigrationInProgress::<T>::exists()
 	}
 }
 
-/// V6: Added storage deposits
+#[impl_trait_for_tuples::impl_for_tuples(10)]
-mod v6 {
+#[tuple_types_custom_trait_bound(Migrate)]
-	use super::*;
+impl MigrateSequence for Tuple {
+	const VERSION_RANGE: (u16, u16) = {
+		let mut versions: (u16, u16) = (0, 0);
+		for_tuples!(
+			#(
+				match versions {
+					(0, 0) => {
+						versions = (Tuple::VERSION, Tuple::VERSION);
+					},
+					(min_version, last_version) if Tuple::VERSION == last_version + 1 => {
+						versions = (min_version, Tuple::VERSION);
+					},
+					_ => panic!("Migrations must be ordered by their versions with no gaps.")
+				}
+			)*
+		);
+		versions
+	};
 
-	#[derive(Encode, Decode)]
+	fn new(version: StorageVersion) -> Cursor {
-	struct OldPrefabWasmModule {
+		for_tuples!(
-		#[codec(compact)]
+			#(
-		instruction_weights_version: u32,
+				if version == Tuple::VERSION {
-		#[codec(compact)]
+					return Tuple::default().encode().try_into().expect(PROOF_ENCODE)
-		initial: u32,
+				}
-		#[codec(compact)]
+			)*
-		maximum: u32,
+		);
-		#[codec(compact)]
+		invalid_version(version)
-		refcount: u64,
-		_reserved: Option<()>,
-		code: Vec<u8>,
-		original_code_len: u32,
-	}
-
-	#[derive(Encode, Decode)]
-	pub struct PrefabWasmModule {
-		#[codec(compact)]
-		pub instruction_weights_version: u32,
-		#[codec(compact)]
-		pub initial: u32,
-		#[codec(compact)]
-		pub maximum: u32,
-		pub code: Vec<u8>,
-	}
-
-	use v5::ContractInfo as OldContractInfo;
-
-	#[derive(Encode, Decode)]
-	pub struct RawContractInfo<CodeHash, Balance> {
-		pub trie_id: TrieId,
-		pub code_hash: CodeHash,
-		pub storage_deposit: Balance,
-	}
-
-	#[derive(Encode, Decode)]
-	pub struct OwnerInfo<T: Config> {
-		owner: T::AccountId,
-		#[codec(compact)]
-		deposit: BalanceOf<T>,
-		#[codec(compact)]
-		refcount: u64,
-	}
-
-	pub type ContractInfo<T> = RawContractInfo<CodeHash<T>, BalanceOf<T>>;
-
-	#[storage_alias]
-	type ContractInfoOf<T: Config> = StorageMap<
-		Pallet<T>,
-		Twox64Concat,
-		<T as frame_system::Config>::AccountId,
-		ContractInfo<T>,
-	>;
-
-	#[storage_alias]
-	type CodeStorage<T: Config> = StorageMap<Pallet<T>, Identity, CodeHash<T>, PrefabWasmModule>;
-
-	#[storage_alias]
-	type OwnerInfoOf<T: Config> = StorageMap<Pallet<T>, Identity, CodeHash<T>, OwnerInfo<T>>;
-
-	pub fn migrate<T: Config>(weight: &mut Weight) {
-		<ContractInfoOf<T>>::translate(|_key, old: OldContractInfo<T>| {
-			weight.saturating_accrue(T::DbWeight::get().reads_writes(1, 1));
-			Some(ContractInfo::<T> {
-				trie_id: old.trie_id,
-				code_hash: old.code_hash,
-				storage_deposit: Default::default(),
-			})
-		});
-
-		let nobody = T::AccountId::decode(&mut sp_runtime::traits::TrailingZeroInput::zeroes())
-			.expect("Infinite input; no dead input space; qed");
-
-		<CodeStorage<T>>::translate(|key, old: OldPrefabWasmModule| {
-			weight.saturating_accrue(T::DbWeight::get().reads_writes(1, 2));
-			<OwnerInfoOf<T>>::insert(
-				key,
-				OwnerInfo {
-					refcount: old.refcount,
-					owner: nobody.clone(),
-					deposit: Default::default(),
-				},
-			);
-			Some(PrefabWasmModule {
-				instruction_weights_version: old.instruction_weights_version,
-				initial: old.initial,
-				maximum: old.maximum,
-				code: old.code,
-			})
-		});
-	}
-}
-
-/// Rename `AccountCounter` to `Nonce`.
-mod v7 {
-	use super::*;
-
-	pub fn migrate<T: Config>(weight: &mut Weight) {
-		#[storage_alias]
-		type AccountCounter<T: Config> = StorageValue<Pallet<T>, u64, ValueQuery>;
-		#[storage_alias]
-		type Nonce<T: Config> = StorageValue<Pallet<T>, u64, ValueQuery>;
-
-		Nonce::<T>::set(AccountCounter::<T>::take());
-		weight.saturating_accrue(T::DbWeight::get().reads_writes(1, 2))
-	}
-}
-
-/// Update `ContractInfo` with new fields that track storage deposits.
-mod v8 {
-	use super::*;
-	use sp_io::default_child_storage as child;
-	use v6::ContractInfo as OldContractInfo;
-
-	#[derive(Encode, Decode)]
-	pub struct ContractInfo<T: Config> {
-		pub trie_id: TrieId,
-		pub code_hash: CodeHash<T>,
-		pub storage_bytes: u32,
-		pub storage_items: u32,
-		pub storage_byte_deposit: BalanceOf<T>,
-		pub storage_item_deposit: BalanceOf<T>,
-		pub storage_base_deposit: BalanceOf<T>,
-	}
-
-	#[storage_alias]
-	type ContractInfoOf<T: Config, V> =
-		StorageMap<Pallet<T>, Twox64Concat, <T as frame_system::Config>::AccountId, V>;
-
-	pub fn migrate<T: Config>(weight: &mut Weight) {
-		<ContractInfoOf<T, ContractInfo<T>>>::translate_values(|old: OldContractInfo<T>| {
-			// Count storage items of this contract
-			let mut storage_bytes = 0u32;
-			let mut storage_items = 0u32;
-			let mut key = Vec::new();
-			while let Some(next) = child::next_key(&old.trie_id, &key) {
-				key = next;
-				let mut val_out = [];
-				let len = child::read(&old.trie_id, &key, &mut val_out, 0)
-					.expect("The loop conditions checks for existence of the key; qed");
-				storage_bytes.saturating_accrue(len);
-				storage_items.saturating_accrue(1);
-			}
-
-			let storage_byte_deposit =
-				T::DepositPerByte::get().saturating_mul(storage_bytes.into());
-			let storage_item_deposit =
-				T::DepositPerItem::get().saturating_mul(storage_items.into());
-			let storage_base_deposit = old
-				.storage_deposit
-				.saturating_sub(storage_byte_deposit)
-				.saturating_sub(storage_item_deposit);
-
-			// Reads: One read for each storage item plus the contract info itself.
-			// Writes: Only the new contract info.
-			weight.saturating_accrue(
-				T::DbWeight::get().reads_writes(u64::from(storage_items) + 1, 1),
-			);
-
-			Some(ContractInfo {
-				trie_id: old.trie_id,
-				code_hash: old.code_hash,
-				storage_bytes,
-				storage_items,
-				storage_byte_deposit,
-				storage_item_deposit,
-				storage_base_deposit,
-			})
-		});
 	}
 
 	#[cfg(feature = "try-runtime")]
-	pub fn pre_upgrade<T: Config>() -> Result<(), TryRuntimeError> {
+	/// Execute the pre-checks of the step associated with this version.
-		use frame_support::traits::ReservableCurrency;
+	fn pre_upgrade_step(version: StorageVersion) -> Result<Vec<u8>, TryRuntimeError> {
-		for (key, value) in ContractInfoOf::<T, OldContractInfo<T>>::iter() {
+		for_tuples!(
-			let reserved = T::Currency::reserved_balance(&key);
+			#(
-			ensure!(reserved >= value.storage_deposit, "Reserved balance out of sync.");
+				if version == Tuple::VERSION {
-		}
+					return Tuple::pre_upgrade_step()
-		Ok(())
+				}
+			)*
+		);
+		invalid_version(version)
+	}
+
+	#[cfg(feature = "try-runtime")]
+	/// Execute the post-checks of the step associated with this version.
+	fn post_upgrade_step(version: StorageVersion, state: Vec<u8>) -> Result<(), TryRuntimeError> {
+		for_tuples!(
+			#(
+				if version == Tuple::VERSION {
+					return Tuple::post_upgrade_step(state)
+				}
+			)*
+		);
+		invalid_version(version)
+	}
+
+	fn steps(version: StorageVersion, mut cursor: &[u8], weight_left: &mut Weight) -> StepResult {
+		for_tuples!(
+			#(
+				if version == Tuple::VERSION {
+					let mut migration = <Tuple as Decode>::decode(&mut cursor)
+						.expect(PROOF_DECODE);
+					let max_weight = Tuple::max_step_weight();
+					let mut steps_done = 0;
+					while weight_left.all_gt(max_weight) {
+						let (finished, weight) = migration.step();
+						steps_done += 1;
+						weight_left.saturating_reduce(weight);
+						if matches!(finished, IsFinished::Yes) {
+							return StepResult::Completed{ steps_done }
+						}
+					}
+					return  StepResult::InProgress{cursor: migration.encode().try_into().expect(PROOF_ENCODE), steps_done }
+				}
+			)*
+		);
+		invalid_version(version)
+	}
+
+	fn integrity_test(max_block_weight: Weight) {
+		for_tuples!(
+			#(
+				Tuple::integrity_test(max_block_weight);
+			)*
+		);
 	}
 }
 
-/// Update `CodeStorage` with the new `determinism` field.
+#[cfg(test)]
-mod v9 {
+mod test {
 	use super::*;
-	use crate::Determinism;
+	use crate::tests::{ExtBuilder, Test};
-	use v6::PrefabWasmModule as OldPrefabWasmModule;
 
-	#[derive(Encode, Decode)]
+	#[derive(Default, Encode, Decode, MaxEncodedLen)]
-	pub struct PrefabWasmModule {
+	struct MockMigration<const N: u16> {
-		#[codec(compact)]
+		// MockMigration<N> needs `N` steps to finish
-		pub instruction_weights_version: u32,
+		count: u16,
-		#[codec(compact)]
-		pub initial: u32,
-		#[codec(compact)]
-		pub maximum: u32,
-		pub code: Vec<u8>,
-		pub determinism: Determinism,
 	}
 
-	#[storage_alias]
+	impl<const N: u16> Migrate for MockMigration<N> {
-	type CodeStorage<T: Config> = StorageMap<Pallet<T>, Identity, CodeHash<T>, PrefabWasmModule>;
+		const VERSION: u16 = N;
+		fn max_step_weight() -> Weight {
+			Weight::from_all(1)
+		}
+		fn step(&mut self) -> (IsFinished, Weight) {
+			assert!(self.count != N);
+			self.count += 1;
+			if self.count == N {
+				(IsFinished::Yes, Weight::from_all(1))
+			} else {
+				(IsFinished::No, Weight::from_all(1))
+			}
+		}
+	}
 
-	pub fn migrate<T: Config>(weight: &mut Weight) {
+	#[test]
-		<CodeStorage<T>>::translate_values(|old: OldPrefabWasmModule| {
+	fn version_range_works() {
-			weight.saturating_accrue(T::DbWeight::get().reads_writes(1, 1));
+		let range = <(MockMigration<1>, MockMigration<2>)>::VERSION_RANGE;
-			Some(PrefabWasmModule {
+		assert_eq!(range, (1, 2));
-				instruction_weights_version: old.instruction_weights_version,
+	}
-				initial: old.initial,
+
-				maximum: old.maximum,
+	#[test]
-				code: old.code,
+	fn is_upgrade_supported_works() {
-				determinism: Determinism::Enforced,
+		type M = (MockMigration<9>, MockMigration<10>, MockMigration<11>);
-			})
+
+		[(1, 1), (8, 11), (9, 11)].into_iter().for_each(|(from, to)| {
+			assert!(
+				M::is_upgrade_supported(StorageVersion::new(from), StorageVersion::new(to)),
+				"{} -> {} is supported",
+				from,
+				to
+			)
+		});
+
+		[(1, 0), (0, 3), (7, 11), (8, 10)].into_iter().for_each(|(from, to)| {
+			assert!(
+				!M::is_upgrade_supported(StorageVersion::new(from), StorageVersion::new(to)),
+				"{} -> {} is not supported",
+				from,
+				to
+			)
+		});
+	}
+
+	#[test]
+	fn steps_works() {
+		type M = (MockMigration<2>, MockMigration<3>);
+		let version = StorageVersion::new(2);
+		let mut cursor = M::new(version);
+
+		let mut weight = Weight::from_all(2);
+		let result = M::steps(version, &cursor, &mut weight);
+		cursor = vec![1u8, 0].try_into().unwrap();
+		assert_eq!(result, StepResult::InProgress { cursor: cursor.clone(), steps_done: 1 });
+		assert_eq!(weight, Weight::from_all(1));
+
+		let mut weight = Weight::from_all(2);
+		assert_eq!(
+			M::steps(version, &cursor, &mut weight),
+			StepResult::Completed { steps_done: 1 }
+		);
+	}
+
+	#[test]
+	fn no_migration_in_progress_works() {
+		type M = (MockMigration<1>, MockMigration<2>);
+		type TestMigration = Migration<Test, M>;
+
+		ExtBuilder::default().build().execute_with(|| {
+			assert_eq!(StorageVersion::get::<Pallet<Test>>(), 2);
+			assert_eq!(TestMigration::migrate(Weight::MAX).0, MigrateResult::NoMigrationInProgress)
+		});
+	}
+
+	#[test]
+	fn migration_works() {
+		type M = (MockMigration<1>, MockMigration<2>);
+		type TestMigration = Migration<Test, M>;
+
+		ExtBuilder::default().set_storage_version(0).build().execute_with(|| {
+			assert_eq!(StorageVersion::get::<Pallet<Test>>(), 0);
+			TestMigration::on_runtime_upgrade();
+			for (version, status) in
+				[(1, MigrateResult::InProgress { steps_done: 1 }), (2, MigrateResult::Completed)]
+			{
+				assert_eq!(TestMigration::migrate(Weight::MAX).0, status);
+				assert_eq!(
+					<Pallet<Test>>::on_chain_storage_version(),
+					StorageVersion::new(version)
+				);
+			}
+
+			assert_eq!(TestMigration::migrate(Weight::MAX).0, MigrateResult::NoMigrationInProgress);
+			assert_eq!(StorageVersion::get::<Pallet<Test>>(), 2);
 		});
 	}
 }
-
-// Post checks always need to be run against the latest storage version. This is why we
-// do not scope them in the per version modules. They always need to be ported to the latest
-// version.
-#[cfg(feature = "try-runtime")]
-mod post_checks {
-	use super::*;
-	use crate::Determinism;
-	use sp_io::default_child_storage as child;
-	use v8::ContractInfo;
-	use v9::PrefabWasmModule;
-
-	#[storage_alias]
-	type CodeStorage<T: Config> = StorageMap<Pallet<T>, Identity, CodeHash<T>, PrefabWasmModule>;
-
-	#[storage_alias]
-	type ContractInfoOf<T: Config, V> =
-		StorageMap<Pallet<T>, Twox64Concat, <T as frame_system::Config>::AccountId, V>;
-
-	pub fn post_upgrade<T: Config>(old_version: StorageVersion) -> Result<(), TryRuntimeError> {
-		if old_version < 7 {
-			return Ok(())
-		}
-
-		if old_version < 8 {
-			v8::<T>()?;
-		}
-
-		if old_version < 9 {
-			v9::<T>()?;
-		}
-
-		Ok(())
-	}
-
-	fn v8<T: Config>() -> Result<(), TryRuntimeError> {
-		use frame_support::traits::ReservableCurrency;
-		for (key, value) in ContractInfoOf::<T, ContractInfo<T>>::iter() {
-			let reserved = T::Currency::reserved_balance(&key);
-			let stored = value
-				.storage_base_deposit
-				.saturating_add(value.storage_byte_deposit)
-				.saturating_add(value.storage_item_deposit);
-			ensure!(reserved >= stored, "Reserved balance out of sync.");
-
-			let mut storage_bytes = 0u32;
-			let mut storage_items = 0u32;
-			let mut key = Vec::new();
-			while let Some(next) = child::next_key(&value.trie_id, &key) {
-				key = next;
-				let mut val_out = [];
-				let len = child::read(&value.trie_id, &key, &mut val_out, 0)
-					.expect("The loop conditions checks for existence of the key; qed");
-				storage_bytes.saturating_accrue(len);
-				storage_items.saturating_accrue(1);
-			}
-			ensure!(storage_bytes == value.storage_bytes, "Storage bytes do not match.");
-			ensure!(storage_items == value.storage_items, "Storage items do not match.");
-		}
-		Ok(())
-	}
-
-	fn v9<T: Config>() -> Result<(), TryRuntimeError> {
-		for value in CodeStorage::<T>::iter_values() {
-			ensure!(
-				value.determinism == Determinism::Enforced,
-				"All pre-existing codes need to be deterministic."
-			);
-		}
-		Ok(())
-	}
-}

substrate/frame/contracts/src/migration/v10.rs

@@ -0,0 +1,272 @@
+// This file is part of Substrate.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Don't rely on reserved balances keeping an account alive
+//! See <https://github.com/paritytech/substrate/pull/13370>.
+
+use crate::{
+	address::AddressGenerator,
+	exec::AccountIdOf,
+	migration::{IsFinished, Migrate},
+	weights::WeightInfo,
+	BalanceOf, CodeHash, Config, Pallet, TrieId, Weight, LOG_TARGET,
+};
+use codec::{Decode, Encode};
+use core::cmp::{max, min};
+use frame_support::{
+	codec,
+	pallet_prelude::*,
+	storage_alias,
+	traits::{
+		fungible::Inspect,
+		tokens::{Fortitude::Polite, Preservation::Preserve},
+		Currency, ExistenceRequirement, ReservableCurrency,
+	},
+	DefaultNoBound,
+};
+use sp_core::hexdisplay::HexDisplay;
+#[cfg(feature = "try-runtime")]
+use sp_runtime::TryRuntimeError;
+use sp_runtime::{traits::Zero, Perbill, Saturating};
+use sp_std::{marker::PhantomData, ops::Deref, prelude::*};
+
+mod old {
+	use super::*;
+
+	#[derive(Encode, Decode, Clone, PartialEq, Eq, RuntimeDebug, TypeInfo, MaxEncodedLen)]
+	#[scale_info(skip_type_params(T))]
+	pub struct ContractInfo<T: Config> {
+		pub trie_id: TrieId,
+		pub code_hash: CodeHash<T>,
+		pub storage_bytes: u32,
+		pub storage_items: u32,
+		pub storage_byte_deposit: BalanceOf<T>,
+		pub storage_item_deposit: BalanceOf<T>,
+		pub storage_base_deposit: BalanceOf<T>,
+	}
+
+	#[storage_alias]
+	pub type ContractInfoOf<T: Config> = StorageMap<
+		Pallet<T>,
+		Twox64Concat,
+		<T as frame_system::Config>::AccountId,
+		ContractInfo<T>,
+	>;
+}
+
+#[cfg(feature = "runtime-benchmarks")]
+pub fn store_old_contrat_info<T: Config>(account: T::AccountId, info: crate::ContractInfo<T>) {
+	let info = old::ContractInfo {
+		trie_id: info.trie_id,
+		code_hash: info.code_hash,
+		storage_bytes: Default::default(),
+		storage_items: Default::default(),
+		storage_byte_deposit: Default::default(),
+		storage_item_deposit: Default::default(),
+		storage_base_deposit: Default::default(),
+	};
+	old::ContractInfoOf::<T>::insert(account, info);
+}
+
+#[derive(Encode, Decode, Clone, PartialEq, Eq, RuntimeDebugNoBound, TypeInfo, MaxEncodedLen)]
+#[scale_info(skip_type_params(T))]
+pub struct DepositAccount<T: Config>(AccountIdOf<T>);
+
+impl<T: Config> Deref for DepositAccount<T> {
+	type Target = AccountIdOf<T>;
+
+	fn deref(&self) -> &Self::Target {
+		&self.0
+	}
+}
+
+#[derive(Encode, Decode, Clone, PartialEq, Eq, RuntimeDebug, TypeInfo, MaxEncodedLen)]
+#[scale_info(skip_type_params(T))]
+pub struct ContractInfo<T: Config> {
+	pub trie_id: TrieId,
+	deposit_account: DepositAccount<T>,
+	pub code_hash: CodeHash<T>,
+	storage_bytes: u32,
+	storage_items: u32,
+	pub storage_byte_deposit: BalanceOf<T>,
+	storage_item_deposit: BalanceOf<T>,
+	storage_base_deposit: BalanceOf<T>,
+}
+
+#[derive(Encode, Decode, MaxEncodedLen, DefaultNoBound)]
+pub struct Migration<T: Config> {
+	last_key: Option<BoundedVec<u8, ConstU32<256>>>,
+	_phantom: PhantomData<T>,
+}
+
+#[storage_alias]
+type ContractInfoOf<T: Config> =
+	StorageMap<Pallet<T>, Twox64Concat, <T as frame_system::Config>::AccountId, ContractInfo<T>>;
+
+impl<T: Config> Migrate for Migration<T> {
+	const VERSION: u16 = 10;
+
+	fn max_step_weight() -> Weight {
+		T::WeightInfo::v10_migration_step()
+	}
+
+	fn step(&mut self) -> (IsFinished, Weight) {
+		let mut iter = if let Some(last_key) = self.last_key.take() {
+			old::ContractInfoOf::<T>::iter_from(last_key.to_vec())
+		} else {
+			old::ContractInfoOf::<T>::iter()
+		};
+
+		if let Some((account, contract)) = iter.next() {
+			let min_balance = Pallet::<T>::min_balance();
+			log::debug!(target: LOG_TARGET, "Account: 0x{} ", HexDisplay::from(&account.encode()));
+
+			// Store last key for next migration step
+			self.last_key = Some(iter.last_raw_key().to_vec().try_into().unwrap());
+
+			// Get the new deposit account address
+			let deposit_account: DepositAccount<T> =
+				DepositAccount(T::AddressGenerator::deposit_address(&account));
+
+			// Calculate the existing deposit, that should be reserved on the contract account
+			let old_deposit = contract
+				.storage_base_deposit
+				.saturating_add(contract.storage_item_deposit)
+				.saturating_add(contract.storage_byte_deposit);
+
+			// Unreserve the existing deposit
+			// Note we can't use repatriate_reserve, because it only works with existing accounts
+			let remaining = T::Currency::unreserve(&account, old_deposit);
+			if !remaining.is_zero() {
+				log::warn!(
+					target: LOG_TARGET,
+					"Partially unreserved. Remaining {:?} out of {:?} asked",
+					remaining,
+					old_deposit
+				);
+			}
+
+			// Attempt to transfer the old deposit to the deposit account.
+			let amount = old_deposit
+				.saturating_sub(min_balance)
+				.min(T::Currency::reducible_balance(&account, Preserve, Polite));
+
+			let new_deposit = T::Currency::transfer(
+				&account,
+				&deposit_account,
+				amount,
+				ExistenceRequirement::KeepAlive,
+			)
+			.map(|_| {
+				log::debug!(
+					target: LOG_TARGET,
+					"Transferred deposit ({:?}) to deposit account",
+					amount
+				);
+				amount
+			})
+			// If it fails we fallback to minting the ED.
+			.unwrap_or_else(|err| {
+				log::error!(target: LOG_TARGET, "Failed to transfer ED, reason: {:?}", err);
+				T::Currency::deposit_creating(&deposit_account, min_balance);
+				min_balance
+			});
+
+			// Calculate the new base_deposit to store in the contract:
+			// Ideally: it should be the same as the old one
+			// Ideally, it should be at least 2xED (for the contract and deposit account).
+			// It can't be more than the `new_deposit`.
+			let new_base_deposit = min(
+				max(contract.storage_base_deposit, min_balance.saturating_add(min_balance)),
+				new_deposit,
+			);
+
+			// Calculate the ratio to adjust storage_byte and storage_item deposits.
+			let new_deposit_without_base = new_deposit.saturating_sub(new_base_deposit);
+			let old_deposit_without_base =
+				old_deposit.saturating_sub(contract.storage_base_deposit);
+			let ratio = Perbill::from_rational(new_deposit_without_base, old_deposit_without_base);
+
+			// Calculate the new storage deposits based on the ratio
+			let storage_byte_deposit = ratio.mul_ceil(contract.storage_byte_deposit);
+			let storage_item_deposit = ratio.mul_ceil(contract.storage_item_deposit);
+
+			// Recalculate the new base deposit, instead of using new_base_deposit to avoid rounding
+			// errors
+			let storage_base_deposit = new_deposit
+				.saturating_sub(storage_byte_deposit)
+				.saturating_sub(storage_item_deposit);
+
+			let new_contract_info = ContractInfo {
+				trie_id: contract.trie_id,
+				deposit_account,
+				code_hash: contract.code_hash,
+				storage_bytes: contract.storage_bytes,
+				storage_items: contract.storage_items,
+				storage_byte_deposit,
+				storage_item_deposit,
+				storage_base_deposit,
+			};
+
+			ContractInfoOf::<T>::insert(&account, new_contract_info);
+			(IsFinished::No, T::WeightInfo::v10_migration_step())
+		} else {
+			log::debug!(target: LOG_TARGET, "Done Migrating contract info");
+			(IsFinished::Yes, T::WeightInfo::v10_migration_step())
+		}
+	}
+
+	#[cfg(feature = "try-runtime")]
+	fn pre_upgrade_step() -> Result<Vec<u8>, TryRuntimeError> {
+		let sample: Vec<_> = old::ContractInfoOf::<T>::iter().take(10).collect();
+
+		log::debug!(target: LOG_TARGET, "Taking sample of {} contracts", sample.len());
+		Ok(sample.encode())
+	}
+
+	#[cfg(feature = "try-runtime")]
+	fn post_upgrade_step(state: Vec<u8>) -> Result<(), TryRuntimeError> {
+		let sample =
+			<Vec<(T::AccountId, old::ContractInfo<T>)> as Decode>::decode(&mut &state[..]).unwrap();
+
+		log::debug!(target: LOG_TARGET, "Validating sample of {} contracts", sample.len());
+		for (account, old_contract) in sample {
+			log::debug!(target: LOG_TARGET, "===");
+			log::debug!(target: LOG_TARGET, "Account: 0x{} ", HexDisplay::from(&account.encode()));
+			let contract = ContractInfoOf::<T>::get(&account).unwrap();
+			ensure!(old_contract.trie_id == contract.trie_id, "invalid trie_id");
+			ensure!(old_contract.code_hash == contract.code_hash, "invalid code_hash");
+			ensure!(old_contract.storage_bytes == contract.storage_bytes, "invalid storage_bytes");
+			ensure!(old_contract.storage_items == contract.storage_items, "invalid storage_items");
+
+			let deposit =
+				<<T as Config>::Currency as frame_support::traits::Currency<_>>::total_balance(
+					&contract.deposit_account,
+				);
+			ensure!(
+				deposit ==
+					contract
+						.storage_base_deposit
+						.saturating_add(contract.storage_item_deposit)
+						.saturating_add(contract.storage_byte_deposit),
+				"deposit mismatch"
+			);
+		}
+
+		Ok(())
+	}
+}

substrate/frame/contracts/src/migration/v11.rs

@@ -0,0 +1,130 @@
+// This file is part of Substrate.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Overflowing bounded DeletionQueue.
+//! See <https://github.com/paritytech/substrate/pull/13702>.
+
+use crate::{
+	migration::{IsFinished, Migrate},
+	weights::WeightInfo,
+	Config, Pallet, TrieId, Weight, LOG_TARGET,
+};
+#[cfg(feature = "try-runtime")]
+use sp_runtime::TryRuntimeError;
+
+use codec::{Decode, Encode};
+use frame_support::{codec, pallet_prelude::*, storage_alias, DefaultNoBound};
+use sp_std::{marker::PhantomData, prelude::*};
+mod old {
+	use super::*;
+
+	#[derive(Encode, Decode, TypeInfo, MaxEncodedLen)]
+	pub struct DeletedContract {
+		pub(crate) trie_id: TrieId,
+	}
+
+	#[storage_alias]
+	pub type DeletionQueue<T: Config> = StorageValue<Pallet<T>, Vec<DeletedContract>>;
+}
+
+#[derive(Encode, Decode, TypeInfo, MaxEncodedLen, DefaultNoBound, Clone)]
+#[scale_info(skip_type_params(T))]
+pub struct DeletionQueueManager<T: Config> {
+	insert_counter: u32,
+	delete_counter: u32,
+	_phantom: PhantomData<T>,
+}
+
+#[cfg(any(feature = "runtime-benchmarks", feature = "try-runtime"))]
+pub fn fill_old_queue<T: Config>(len: usize) {
+	let queue: Vec<old::DeletedContract> =
+		core::iter::repeat_with(|| old::DeletedContract { trie_id: Default::default() })
+			.take(len)
+			.collect();
+	old::DeletionQueue::<T>::set(Some(queue));
+}
+
+#[storage_alias]
+type DeletionQueue<T: Config> = StorageMap<Pallet<T>, Twox64Concat, u32, TrieId>;
+
+#[storage_alias]
+type DeletionQueueCounter<T: Config> = StorageValue<Pallet<T>, DeletionQueueManager<T>, ValueQuery>;
+
+#[derive(Encode, Decode, MaxEncodedLen, DefaultNoBound)]
+pub struct Migration<T: Config> {
+	_phantom: PhantomData<T>,
+}
+
+impl<T: Config> Migrate for Migration<T> {
+	const VERSION: u16 = 11;
+
+	// It would be more correct to make our use the now removed [DeletionQueueDepth](https://github.com/paritytech/substrate/pull/13702/files#diff-70e9723e9db62816e35f6f885b6770a8449c75a6c2733e9fa7a245fe52c4656c)
+	// but in practice the queue is always empty, so 128 is a good enough approximation for not
+	// underestimating the weight of our migration.
+	fn max_step_weight() -> Weight {
+		T::WeightInfo::v11_migration_step(128)
+	}
+
+	fn step(&mut self) -> (IsFinished, Weight) {
+		let Some(old_queue) = old::DeletionQueue::<T>::take() else { return (IsFinished::Yes, Weight::zero()) };
+		let len = old_queue.len();
+
+		log::debug!(
+			target: LOG_TARGET,
+			"Migrating deletion queue with {} deleted contracts",
+			old_queue.len()
+		);
+
+		if !old_queue.is_empty() {
+			let mut queue = DeletionQueueManager::<T>::default();
+			for contract in old_queue {
+				<DeletionQueue<T>>::insert(queue.insert_counter, contract.trie_id);
+				queue.insert_counter += 1;
+			}
+
+			<DeletionQueueCounter<T>>::set(queue);
+		}
+
+		(IsFinished::Yes, T::WeightInfo::v11_migration_step(len as u32))
+	}
+
+	#[cfg(feature = "try-runtime")]
+	fn pre_upgrade_step() -> Result<Vec<u8>, TryRuntimeError> {
+		let old_queue = old::DeletionQueue::<T>::take().unwrap_or_default();
+
+		if old_queue.is_empty() {
+			let len = 10u32;
+			log::debug!(
+				target: LOG_TARGET,
+				"Injecting {len} entries to deletion queue to test migration"
+			);
+			fill_old_queue::<T>(len as usize);
+			return Ok(len.encode())
+		}
+
+		Ok((old_queue.len() as u32).encode())
+	}
+
+	#[cfg(feature = "try-runtime")]
+	fn post_upgrade_step(state: Vec<u8>) -> Result<(), TryRuntimeError> {
+		let len = <u32 as Decode>::decode(&mut &state[..]).unwrap();
+		let counter = <DeletionQueueCounter<T>>::get();
+		ensure!(counter.insert_counter == len, "invalid insert counter");
+		ensure!(counter.delete_counter == 0, "invalid delete counter");
+		Ok(())
+	}
+}

substrate/frame/contracts/src/migration/v9.rs

@@ -0,0 +1,149 @@
+// This file is part of Substrate.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Update `CodeStorage` with the new `determinism` field.
+
+use crate::{
+	migration::{IsFinished, Migrate},
+	weights::WeightInfo,
+	CodeHash, Config, Determinism, Pallet, Weight, LOG_TARGET,
+};
+use codec::{Decode, Encode};
+use frame_support::{
+	codec, pallet_prelude::*, storage_alias, BoundedVec, DefaultNoBound, Identity,
+};
+#[cfg(feature = "try-runtime")]
+use sp_runtime::TryRuntimeError;
+use sp_std::{marker::PhantomData, prelude::*};
+
+mod old {
+	use super::*;
+
+	#[derive(Encode, Decode)]
+	pub struct PrefabWasmModule {
+		#[codec(compact)]
+		pub instruction_weights_version: u32,
+		#[codec(compact)]
+		pub initial: u32,
+		#[codec(compact)]
+		pub maximum: u32,
+		pub code: Vec<u8>,
+	}
+
+	#[storage_alias]
+	pub type CodeStorage<T: Config> =
+		StorageMap<Pallet<T>, Identity, CodeHash<T>, PrefabWasmModule>;
+}
+
+#[cfg(feature = "runtime-benchmarks")]
+pub fn store_old_dummy_code<T: Config>(len: usize) {
+	use sp_runtime::traits::Hash;
+	let module = old::PrefabWasmModule {
+		instruction_weights_version: 0,
+		initial: 0,
+		maximum: 0,
+		code: vec![42u8; len],
+	};
+	let hash = T::Hashing::hash(&module.code);
+	old::CodeStorage::<T>::insert(hash, module);
+}
+
+#[derive(Encode, Decode)]
+struct PrefabWasmModule {
+	#[codec(compact)]
+	pub instruction_weights_version: u32,
+	#[codec(compact)]
+	pub initial: u32,
+	#[codec(compact)]
+	pub maximum: u32,
+	pub code: Vec<u8>,
+	pub determinism: Determinism,
+}
+
+#[storage_alias]
+type CodeStorage<T: Config> = StorageMap<Pallet<T>, Identity, CodeHash<T>, PrefabWasmModule>;
+
+#[derive(Encode, Decode, MaxEncodedLen, DefaultNoBound)]
+pub struct Migration<T: Config> {
+	last_key: Option<BoundedVec<u8, ConstU32<256>>>,
+	_phantom: PhantomData<T>,
+}
+
+impl<T: Config> Migrate for Migration<T> {
+	const VERSION: u16 = 9;
+
+	fn max_step_weight() -> Weight {
+		T::WeightInfo::v9_migration_step(T::MaxCodeLen::get())
+	}
+
+	fn step(&mut self) -> (IsFinished, Weight) {
+		let mut iter = if let Some(last_key) = self.last_key.take() {
+			old::CodeStorage::<T>::iter_from(last_key.to_vec())
+		} else {
+			old::CodeStorage::<T>::iter()
+		};
+
+		if let Some((key, old)) = iter.next() {
+			log::debug!(target: LOG_TARGET, "Migrating contract code {:?}", key);
+			let len = old.code.len() as u32;
+			let module = PrefabWasmModule {
+				instruction_weights_version: old.instruction_weights_version,
+				initial: old.initial,
+				maximum: old.maximum,
+				code: old.code,
+				determinism: Determinism::Enforced,
+			};
+			CodeStorage::<T>::insert(key, module);
+			self.last_key = Some(iter.last_raw_key().to_vec().try_into().unwrap());
+			(IsFinished::No, T::WeightInfo::v9_migration_step(len))
+		} else {
+			log::debug!(target: LOG_TARGET, "No more contracts code to migrate");
+			(IsFinished::Yes, T::WeightInfo::v9_migration_step(0))
+		}
+	}
+
+	#[cfg(feature = "try-runtime")]
+	fn pre_upgrade_step() -> Result<Vec<u8>, TryRuntimeError> {
+		let sample: Vec<_> = old::CodeStorage::<T>::iter().take(100).collect();
+
+		log::debug!(target: LOG_TARGET, "Taking sample of {} contract codes", sample.len());
+		Ok(sample.encode())
+	}
+
+	#[cfg(feature = "try-runtime")]
+	fn post_upgrade_step(state: Vec<u8>) -> Result<(), TryRuntimeError> {
+		let sample =
+			<Vec<(CodeHash<T>, old::PrefabWasmModule)> as Decode>::decode(&mut &state[..]).unwrap();
+
+		log::debug!(target: LOG_TARGET, "Validating sample of {} contract codes", sample.len());
+		for (code_hash, old) in sample {
+			let module = CodeStorage::<T>::get(&code_hash).unwrap();
+			ensure!(
+				module.instruction_weights_version == old.instruction_weights_version,
+				"invalid isntruction weights version"
+			);
+			ensure!(module.determinism == Determinism::Enforced, "invalid determinism");
+			ensure!(module.initial == old.initial, "invalid initial");
+			ensure!(module.maximum == old.maximum, "invalid maximum");
+			ensure!(module.code == old.code, "invalid code");
+			ensure!(module.maximum == old.maximum, "invalid maximum");
+			ensure!(module.code == old.code, "invalid code");
+		}
+
+		Ok(())
+	}
+}

substrate/frame/contracts/src/tests.rs

@@ -28,7 +28,8 @@ use crate::{
 	wasm::{Determinism, PrefabWasmModule, ReturnCode as RuntimeReturnCode},
 	weights::WeightInfo,
 	BalanceOf, Code, CodeStorage, CollectEvents, Config, ContractInfo, ContractInfoOf, DebugInfo,
-	DefaultAddressGenerator, DeletionQueueCounter, Error, Origin, Pallet, Schedule,
+	DefaultAddressGenerator, DeletionQueueCounter, Error, MigrationInProgress, Origin, Pallet,
+	Schedule,
 };
 use assert_matches::assert_matches;
 use codec::Encode;
@@ -39,7 +40,7 @@ use frame_support::{
 	storage::child,
 	traits::{
 		ConstU32, ConstU64, Contains, Currency, ExistenceRequirement, LockableCurrency, OnIdle,
-		OnInitialize, WithdrawReasons,
+		OnInitialize, StorageVersion, WithdrawReasons,
 	},
 	weights::{constants::WEIGHT_REF_TIME_PER_SECOND, Weight},
 };
@@ -438,10 +439,11 @@ pub const GAS_LIMIT: Weight = Weight::from_parts(100_000_000_000, 3 * 1024 * 102
 
 pub struct ExtBuilder {
 	existential_deposit: u64,
+	storage_version: Option<StorageVersion>,
 }
 impl Default for ExtBuilder {
 	fn default() -> Self {
-		Self { existential_deposit: ExistentialDeposit::get() }
+		Self { existential_deposit: ExistentialDeposit::get(), storage_version: None }
 	}
 }
 impl ExtBuilder {
@@ -452,6 +454,10 @@ impl ExtBuilder {
 	pub fn set_associated_consts(&self) {
 		EXISTENTIAL_DEPOSIT.with(|v| *v.borrow_mut() = self.existential_deposit);
 	}
+	pub fn set_storage_version(mut self, version: u16) -> Self {
+		self.storage_version = Some(StorageVersion::new(version));
+		self
+	}
 	pub fn build(self) -> sp_io::TestExternalities {
 		use env_logger::{Builder, Env};
 		let env = Env::new().default_filter_or("runtime=debug");
@@ -463,7 +469,15 @@ impl ExtBuilder {
 			.unwrap();
 		let mut ext = sp_io::TestExternalities::new(t);
 		ext.register_extension(KeystoreExt::new(MemoryKeystore::new()));
-		ext.execute_with(|| System::set_block_number(1));
+		ext.execute_with(|| {
+			use frame_support::traits::OnGenesis;
+
+			Pallet::<Test>::on_genesis();
+			if let Some(storage_version) = self.storage_version {
+				storage_version.put::<Pallet<Test>>();
+			}
+			System::set_block_number(1)
+		});
 		ext
 	}
 }
@@ -544,6 +558,62 @@ fn calling_plain_account_fails() {
 	});
 }
 
+#[test]
+fn migration_in_progress_works() {
+	let (wasm, code_hash) = compile_module::<Test>("dummy").unwrap();
+
+	ExtBuilder::default().existential_deposit(1).build().execute_with(|| {
+		let _ = Balances::deposit_creating(&ALICE, 1_000_000);
+		MigrationInProgress::<Test>::set(Some(Default::default()));
+
+		assert_err!(
+			Contracts::upload_code(
+				RuntimeOrigin::signed(ALICE),
+				vec![],
+				None,
+				Determinism::Enforced
+			),
+			Error::<Test>::MigrationInProgress,
+		);
+		assert_err!(
+			Contracts::remove_code(RuntimeOrigin::signed(ALICE), code_hash),
+			Error::<Test>::MigrationInProgress,
+		);
+		assert_err!(
+			Contracts::set_code(RuntimeOrigin::signed(ALICE), BOB.clone(), code_hash),
+			Error::<Test>::MigrationInProgress,
+		);
+		assert_err_ignore_postinfo!(
+			Contracts::call(RuntimeOrigin::signed(ALICE), BOB, 0, GAS_LIMIT, None, vec![],),
+			Error::<Test>::MigrationInProgress,
+		);
+		assert_err_ignore_postinfo!(
+			Contracts::instantiate_with_code(
+				RuntimeOrigin::signed(ALICE),
+				100_000,
+				GAS_LIMIT,
+				None,
+				wasm,
+				vec![],
+				vec![],
+			),
+			Error::<Test>::MigrationInProgress,
+		);
+		assert_err_ignore_postinfo!(
+			Contracts::instantiate(
+				RuntimeOrigin::signed(ALICE),
+				100_000,
+				GAS_LIMIT,
+				None,
+				code_hash,
+				vec![],
+				vec![],
+			),
+			Error::<Test>::MigrationInProgress,
+		);
+	});
+}
+
 #[test]
 fn instantiate_and_call_and_deposit_event() {
 	let (wasm, code_hash) = compile_module::<Test>("event_and_return_on_deploy").unwrap();

substrate/frame/support/src/traits/metadata.rs

@@ -20,7 +20,7 @@
 use codec::{Decode, Encode};
 use impl_trait_for_tuples::impl_for_tuples;
 use sp_runtime::RuntimeDebug;
-use sp_std::prelude::*;
+use sp_std::{ops::Add, prelude::*};
 
 /// Provides information about the pallet itself and its setup in the runtime.
 ///
@@ -232,6 +232,14 @@ impl PartialOrd<u16> for StorageVersion {
 	}
 }
 
+impl Add<u16> for StorageVersion {
+	type Output = StorageVersion;
+
+	fn add(self, rhs: u16) -> Self::Output {
+		Self::new(self.0 + rhs)
+	}
+}
+
 /// Special marker struct if no storage version is set for a pallet.
 ///
 /// If you (the reader) end up here, it probably means that you tried to compare