Bounties Pallet to FrameV2 (#9566)

* migrate bounties pallet * events in tests * test import event * Update frame/bounties/src/lib.rs Co-authored-by: Keith Yeung <kungfukeith11@gmail.com> * cargo fmt * line width * benchmarks compile * add migrations * fmt * comments * mod migrations * fix Cargo.toml * never remember cargo fmt * fix migration * migrations and test * change checks in migration * remove unused values * Update frame/bounties/src/migrations/v4.rs * cargo fmt * fix benchmarking * trigger ci Co-authored-by: Keith Yeung <kungfukeith11@gmail.com> Co-authored-by: Guillaume Thiolliere <gui.thiolliere@gmail.com>
2026-05-30 04:41:03 +00:00 · 2021-09-21 09:07:36 -04:00
parent e2dcb4b657
commit eca9af1a0a
7 changed files with 561 additions and 234 deletions
@@ -5121,6 +5121,7 @@ dependencies = [
 "frame-benchmarking",
 "frame-support",
 "frame-system",
+ "log 0.4.14",
 "pallet-balances",
 "pallet-treasury",
 "parity-scale-codec",
@@ -22,24 +22,27 @@ sp-runtime = { version = "4.0.0-dev", default-features = false, path = "../../pr
 frame-support = { version = "4.0.0-dev", default-features = false, path = "../support" }
 frame-system = { version = "4.0.0-dev", default-features = false, path = "../system" }
 pallet-treasury = { version = "4.0.0-dev", default-features = false, path = "../treasury" }
-
+sp-io = { version = "4.0.0-dev", path = "../../primitives/io", default-features = false }
+sp-core = { version = "4.0.0-dev", path = "../../primitives/core", default-features = false }
 frame-benchmarking = { version = "4.0.0-dev", default-features = false, path = "../benchmarking", optional = true }
+log = { version = "0.4.14", default-features = false }

 [dev-dependencies]
-sp-io = { version = "4.0.0-dev", path = "../../primitives/io" }
-sp-core = { version = "4.0.0-dev", path = "../../primitives/core" }
 pallet-balances = { version = "4.0.0-dev", path = "../balances" }

 [features]
 default = ["std"]
 std = [
 	"codec/std",
+	"sp-core/std",
+	"sp-io/std",
 	"scale-info/std",
 	"sp-std/std",
 	"sp-runtime/std",
 	"frame-support/std",
 	"frame-system/std",
 	"pallet-treasury/std",
+	"log/std",
 ]
 runtime-benchmarks = [
 	"frame-benchmarking",
@@ -22,11 +22,10 @@
 use super::*;

 use frame_benchmarking::{account, benchmarks, impl_benchmark_test_suite, whitelisted_caller};
-use frame_support::traits::OnInitialize;
 use frame_system::RawOrigin;
 use sp_runtime::traits::Bounded;

-use crate::Module as Bounties;
+use crate::Pallet as Bounties;
 use pallet_treasury::Pallet as Treasury;

 const SEED: u32 = 0;
@@ -36,10 +35,10 @@ fn create_approved_bounties<T: Config>(n: u32) -> Result<(), &'static str> {
 	for i in 0..n {
 		let (caller, _curator, _fee, value, reason) = setup_bounty::<T>(i, MAX_BYTES);
 		Bounties::<T>::propose_bounty(RawOrigin::Signed(caller).into(), value, reason)?;
-		let bounty_id = BountyCount::get() - 1;
+		let bounty_id = BountyCount::<T>::get() - 1;
 		Bounties::<T>::approve_bounty(RawOrigin::Root.into(), bounty_id)?;
 	}
-	ensure!(BountyApprovals::get().len() == n as usize, "Not all bounty approved");
+	ensure!(BountyApprovals::<T>::get().len() == n as usize, "Not all bounty approved");
 	Ok(())
 }

@@ -64,7 +63,7 @@ fn create_bounty<T: Config>(
 	let (caller, curator, fee, value, reason) = setup_bounty::<T>(0, MAX_BYTES);
 	let curator_lookup = T::Lookup::unlookup(curator.clone());
 	Bounties::<T>::propose_bounty(RawOrigin::Signed(caller).into(), value, reason)?;
-	let bounty_id = BountyCount::get() - 1;
+	let bounty_id = BountyCount::<T>::get() - 1;
 	Bounties::<T>::approve_bounty(RawOrigin::Root.into(), bounty_id)?;
 	Treasury::<T>::on_initialize(T::BlockNumber::zero());
 	Bounties::<T>::propose_curator(RawOrigin::Root.into(), bounty_id, curator_lookup.clone(), fee)?;
@@ -94,7 +93,7 @@ benchmarks! {
 	approve_bounty {
 		let (caller, curator, fee, value, reason) = setup_bounty::<T>(0, MAX_BYTES);
 		Bounties::<T>::propose_bounty(RawOrigin::Signed(caller).into(), value, reason)?;
-		let bounty_id = BountyCount::get() - 1;
+		let bounty_id = BountyCount::<T>::get() - 1;
 	}: _(RawOrigin::Root, bounty_id)

 	propose_curator {
@@ -102,7 +101,7 @@ benchmarks! {
 		let (caller, curator, fee, value, reason) = setup_bounty::<T>(0, MAX_BYTES);
 		let curator_lookup = T::Lookup::unlookup(curator.clone());
 		Bounties::<T>::propose_bounty(RawOrigin::Signed(caller).into(), value, reason)?;
-		let bounty_id = BountyCount::get() - 1;
+		let bounty_id = BountyCount::<T>::get() - 1;
 		Bounties::<T>::approve_bounty(RawOrigin::Root.into(), bounty_id)?;
 		Bounties::<T>::on_initialize(T::BlockNumber::zero());
 	}: _(RawOrigin::Root, bounty_id, curator_lookup, fee)
@@ -112,7 +111,7 @@ benchmarks! {
 		setup_pot_account::<T>();
 		let (curator_lookup, bounty_id) = create_bounty::<T>()?;
 		Bounties::<T>::on_initialize(T::BlockNumber::zero());
-		let bounty_id = BountyCount::get() - 1;
+		let bounty_id = BountyCount::<T>::get() - 1;
 		frame_system::Pallet::<T>::set_block_number(T::BountyUpdatePeriod::get() + 1u32.into());
 		let caller = whitelisted_caller();
 	}: _(RawOrigin::Signed(caller), bounty_id)
@@ -122,7 +121,7 @@ benchmarks! {
 		let (caller, curator, fee, value, reason) = setup_bounty::<T>(0, MAX_BYTES);
 		let curator_lookup = T::Lookup::unlookup(curator.clone());
 		Bounties::<T>::propose_bounty(RawOrigin::Signed(caller).into(), value, reason)?;
-		let bounty_id = BountyCount::get() - 1;
+		let bounty_id = BountyCount::<T>::get() - 1;
 		Bounties::<T>::approve_bounty(RawOrigin::Root.into(), bounty_id)?;
 		Bounties::<T>::on_initialize(T::BlockNumber::zero());
 		Bounties::<T>::propose_curator(RawOrigin::Root.into(), bounty_id, curator_lookup, fee)?;
@@ -133,7 +132,7 @@ benchmarks! {
 		let (curator_lookup, bounty_id) = create_bounty::<T>()?;
 		Bounties::<T>::on_initialize(T::BlockNumber::zero());

-		let bounty_id = BountyCount::get() - 1;
+		let bounty_id = BountyCount::<T>::get() - 1;
 		let curator = T::Lookup::lookup(curator_lookup).map_err(<&str>::from)?;

 		let beneficiary = T::Lookup::unlookup(account("beneficiary", 0, SEED));
@@ -144,10 +143,9 @@ benchmarks! {
 		let (curator_lookup, bounty_id) = create_bounty::<T>()?;
 		Bounties::<T>::on_initialize(T::BlockNumber::zero());

-		let bounty_id = BountyCount::get() - 1;
+		let bounty_id = BountyCount::<T>::get() - 1;
 		let curator = T::Lookup::lookup(curator_lookup).map_err(<&str>::from)?;

-
 		let beneficiary_account: T::AccountId = account("beneficiary", 0, SEED);
 		let beneficiary = T::Lookup::unlookup(beneficiary_account.clone());
 		Bounties::<T>::award_bounty(RawOrigin::Signed(curator.clone()).into(), bounty_id, beneficiary)?;
@@ -164,17 +162,17 @@ benchmarks! {
 		setup_pot_account::<T>();
 		let (caller, curator, fee, value, reason) = setup_bounty::<T>(0, 0);
 		Bounties::<T>::propose_bounty(RawOrigin::Signed(caller).into(), value, reason)?;
-		let bounty_id = BountyCount::get() - 1;
+		let bounty_id = BountyCount::<T>::get() - 1;
 	}: close_bounty(RawOrigin::Root, bounty_id)

 	close_bounty_active {
 		setup_pot_account::<T>();
 		let (curator_lookup, bounty_id) = create_bounty::<T>()?;
 		Bounties::<T>::on_initialize(T::BlockNumber::zero());
-		let bounty_id = BountyCount::get() - 1;
+		let bounty_id = BountyCount::<T>::get() - 1;
 	}: close_bounty(RawOrigin::Root, bounty_id)
 	verify {
-		assert_last_event::<T>(RawEvent::BountyCanceled(bounty_id).into())
+		assert_last_event::<T>(Event::BountyCanceled(bounty_id).into())
 	}

 	extend_bounty_expiry {
@@ -182,11 +180,11 @@ benchmarks! {
 		let (curator_lookup, bounty_id) = create_bounty::<T>()?;
 		Bounties::<T>::on_initialize(T::BlockNumber::zero());

-		let bounty_id = BountyCount::get() - 1;
+		let bounty_id = BountyCount::<T>::get() - 1;
 		let curator = T::Lookup::lookup(curator_lookup).map_err(<&str>::from)?;
 	}: _(RawOrigin::Signed(curator), bounty_id, Vec::new())
 	verify {
-		assert_last_event::<T>(RawEvent::BountyExtended(bounty_id).into())
+		assert_last_event::<T>(Event::BountyExtended(bounty_id).into())
 	}

 	spend_funds {
@@ -209,7 +207,7 @@ benchmarks! {
 	verify {
 		ensure!(budget_remaining < BalanceOf::<T>::max_value(), "Budget not used");
 		ensure!(missed_any == false, "Missed some");
-		assert_last_event::<T>(RawEvent::BountyBecameActive(b - 1).into())
+		assert_last_event::<T>(Event::BountyBecameActive(b - 1).into())
 	}
 }

@@ -75,13 +75,12 @@
 #![cfg_attr(not(feature = "std"), no_std)]

 mod benchmarking;
+pub mod migrations;
 mod tests;
 pub mod weights;

 use sp_std::prelude::*;

-use frame_support::{decl_error, decl_event, decl_module, decl_storage, ensure};
-
 use frame_support::traits::{
 	Currency, ExistenceRequirement::AllowDeath, Get, Imbalance, OnUnbalanced, ReservableCurrency,
 };
@@ -93,46 +92,17 @@ use sp_runtime::{

 use frame_support::{dispatch::DispatchResultWithPostInfo, traits::EnsureOrigin};

-use frame_support::weights::Weight;
-
-use codec::{Decode, Encode};
-use frame_system::{self as system, ensure_signed};
+use frame_support::pallet_prelude::*;
+use frame_system::pallet_prelude::*;
 use scale_info::TypeInfo;
 pub use weights::WeightInfo;

+pub use pallet::*;
+
 type BalanceOf<T> = pallet_treasury::BalanceOf<T>;

 type PositiveImbalanceOf<T> = pallet_treasury::PositiveImbalanceOf<T>;

-pub trait Config: frame_system::Config + pallet_treasury::Config {
-	/// The amount held on deposit for placing a bounty proposal.
-	type BountyDepositBase: Get<BalanceOf<Self>>;
-
-	/// The delay period for which a bounty beneficiary need to wait before claim the payout.
-	type BountyDepositPayoutDelay: Get<Self::BlockNumber>;
-
-	/// Bounty duration in blocks.
-	type BountyUpdatePeriod: Get<Self::BlockNumber>;
-
-	/// Percentage of the curator fee that will be reserved upfront as deposit for bounty curator.
-	type BountyCuratorDeposit: Get<Permill>;
-
-	/// Minimum value for a bounty.
-	type BountyValueMinimum: Get<BalanceOf<Self>>;
-
-	/// The amount held on deposit per byte within the tip report reason or bounty description.
-	type DataDepositPerByte: Get<BalanceOf<Self>>;
-
-	/// The overarching event type.
-	type Event: From<Event<Self>> + Into<<Self as frame_system::Config>::Event>;
-
-	/// Maximum acceptable reason length.
-	type MaximumReasonLength: Get<u32>;
-
-	/// Weight information for extrinsics in this pallet.
-	type WeightInfo: WeightInfo;
-}
-
 /// An index of a bounty. Just a `u32`.
 pub type BountyIndex = u32;

@@ -186,55 +156,54 @@ pub enum BountyStatus<AccountId, BlockNumber> {
 	},
 }

-// Note :: For backward compatibility reasons,
-// pallet-bounties uses Treasury for storage.
-// This is temporary solution, soon will get replaced with
-// Own storage identifier.
-decl_storage! {
-	trait Store for Module<T: Config> as Treasury {
+#[frame_support::pallet]
+pub mod pallet {
+	use super::*;

-		/// Number of bounty proposals that have been made.
-		pub BountyCount get(fn bounty_count): BountyIndex;
+	#[pallet::pallet]
+	#[pallet::generate_store(pub(super) trait Store)]
+	pub struct Pallet<T>(_);

-		/// Bounties that have been made.
-		pub Bounties get(fn bounties):
-		map hasher(twox_64_concat) BountyIndex
-		=> Option<Bounty<T::AccountId, BalanceOf<T>, T::BlockNumber>>;
+	#[pallet::config]
+	pub trait Config: frame_system::Config + pallet_treasury::Config {
+		/// The amount held on deposit for placing a bounty proposal.
+		#[pallet::constant]
+		type BountyDepositBase: Get<BalanceOf<Self>>;

-		/// The description of each bounty.
-		pub BountyDescriptions get(fn bounty_descriptions): map hasher(twox_64_concat) BountyIndex => Option<Vec<u8>>;
+		/// The delay period for which a bounty beneficiary need to wait before claim the payout.
+		#[pallet::constant]
+		type BountyDepositPayoutDelay: Get<Self::BlockNumber>;

-		/// Bounty indices that have been approved but not yet funded.
-		pub BountyApprovals get(fn bounty_approvals): Vec<BountyIndex>;
+		/// Bounty duration in blocks.
+		#[pallet::constant]
+		type BountyUpdatePeriod: Get<Self::BlockNumber>;
+
+		/// Percentage of the curator fee that will be reserved upfront as deposit for bounty
+		/// curator.
+		#[pallet::constant]
+		type BountyCuratorDeposit: Get<Permill>;
+
+		/// Minimum value for a bounty.
+		#[pallet::constant]
+		type BountyValueMinimum: Get<BalanceOf<Self>>;
+
+		/// The amount held on deposit per byte within the tip report reason or bounty description.
+		#[pallet::constant]
+		type DataDepositPerByte: Get<BalanceOf<Self>>;
+
+		/// The overarching event type.
+		type Event: From<Event<Self>> + IsType<<Self as frame_system::Config>::Event>;
+
+		/// Maximum acceptable reason length.
+		#[pallet::constant]
+		type MaximumReasonLength: Get<u32>;
+
+		/// Weight information for extrinsics in this pallet.
+		type WeightInfo: WeightInfo;
 	}
-}

-decl_event!(
-	pub enum Event<T>
-	where
-		Balance = BalanceOf<T>,
-		<T as frame_system::Config>::AccountId,
-	{
-		/// New bounty proposal. \[index\]
-		BountyProposed(BountyIndex),
-		/// A bounty proposal was rejected; funds were slashed. \[index, bond\]
-		BountyRejected(BountyIndex, Balance),
-		/// A bounty proposal is funded and became active. \[index\]
-		BountyBecameActive(BountyIndex),
-		/// A bounty is awarded to a beneficiary. \[index, beneficiary\]
-		BountyAwarded(BountyIndex, AccountId),
-		/// A bounty is claimed by beneficiary. \[index, payout, beneficiary\]
-		BountyClaimed(BountyIndex, Balance, AccountId),
-		/// A bounty is cancelled. \[index\]
-		BountyCanceled(BountyIndex),
-		/// A bounty expiry is extended. \[index\]
-		BountyExtended(BountyIndex),
-	}
-);
-
-decl_error! {
-	/// Error for the treasury module.
-	pub enum Error for Module<T: Config> {
+	#[pallet::error]
+	pub enum Error<T> {
 		/// Proposer's balance is too low.
 		InsufficientProposersBalance,
 		/// No proposal or bounty at that index.
@@ -255,38 +224,53 @@ decl_error! {
 		/// The bounties cannot be claimed/closed because it's still in the countdown period.
 		Premature,
 	}
-}

-decl_module! {
-	pub struct Module<T: Config>
-		for enum Call
-		where origin: T::Origin
-	{
-		/// The amount held on deposit per byte within bounty description.
-		const DataDepositPerByte: BalanceOf<T> = T::DataDepositPerByte::get();
+	#[pallet::event]
+	#[pallet::generate_deposit(pub(super) fn deposit_event)]
+	pub enum Event<T: Config> {
+		/// New bounty proposal. \[index\]
+		BountyProposed(BountyIndex),
+		/// A bounty proposal was rejected; funds were slashed. \[index, bond\]
+		BountyRejected(BountyIndex, BalanceOf<T>),
+		/// A bounty proposal is funded and became active. \[index\]
+		BountyBecameActive(BountyIndex),
+		/// A bounty is awarded to a beneficiary. \[index, beneficiary\]
+		BountyAwarded(BountyIndex, T::AccountId),
+		/// A bounty is claimed by beneficiary. \[index, payout, beneficiary\]
+		BountyClaimed(BountyIndex, BalanceOf<T>, T::AccountId),
+		/// A bounty is cancelled. \[index\]
+		BountyCanceled(BountyIndex),
+		/// A bounty expiry is extended. \[index\]
+		BountyExtended(BountyIndex),
+	}

-		/// The amount held on deposit for placing a bounty proposal.
-		const BountyDepositBase: BalanceOf<T> = T::BountyDepositBase::get();
+	/// Number of bounty proposals that have been made.
+	#[pallet::storage]
+	#[pallet::getter(fn bounty_count)]
+	pub type BountyCount<T: Config> = StorageValue<_, BountyIndex, ValueQuery>;

-		/// The delay period for which a bounty beneficiary need to wait before claim the payout.
-		const BountyDepositPayoutDelay: T::BlockNumber = T::BountyDepositPayoutDelay::get();
+	/// Bounties that have been made.
+	#[pallet::storage]
+	#[pallet::getter(fn bounties)]
+	pub type Bounties<T: Config> = StorageMap<
+		_,
+		Twox64Concat,
+		BountyIndex,
+		Bounty<T::AccountId, BalanceOf<T>, T::BlockNumber>,
+	>;

-		/// Bounty duration in blocks.
-		const BountyUpdatePeriod: T::BlockNumber = T::BountyUpdatePeriod::get();
+	/// The description of each bounty.
+	#[pallet::storage]
+	#[pallet::getter(fn bounty_descriptions)]
+	pub type BountyDescriptions<T: Config> = StorageMap<_, Twox64Concat, BountyIndex, Vec<u8>>;

-		/// Percentage of the curator fee that will be reserved upfront as deposit for bounty curator.
-		const BountyCuratorDeposit: Permill = T::BountyCuratorDeposit::get();
-
-		/// Minimum value for a bounty.
-		const BountyValueMinimum: BalanceOf<T> = T::BountyValueMinimum::get();
-
-		/// Maximum acceptable reason length.
-		const MaximumReasonLength: u32 = T::MaximumReasonLength::get();
-
-		type Error = Error<T>;
-
-		fn deposit_event() = default;
+	/// Bounty indices that have been approved but not yet funded.
+	#[pallet::storage]
+	#[pallet::getter(fn bounty_approvals)]
+	pub type BountyApprovals<T: Config> = StorageValue<_, Vec<BountyIndex>, ValueQuery>;

+	#[pallet::call]
+	impl<T: Config> Pallet<T> {
 		/// Propose a new bounty.
 		///
 		/// The dispatch origin for this call must be _Signed_.
@@ -299,14 +283,15 @@ decl_module! {
 		/// - `fee`: The curator fee.
 		/// - `value`: The total payment amount of this bounty, curator fee included.
 		/// - `description`: The description of this bounty.
-		#[weight = <T as Config>::WeightInfo::propose_bounty(description.len() as u32)]
-		fn propose_bounty(
-			origin,
-			#[compact] value: BalanceOf<T>,
+		#[pallet::weight(<T as Config>::WeightInfo::propose_bounty(description.len() as u32))]
+		pub fn propose_bounty(
+			origin: OriginFor<T>,
+			#[pallet::compact] value: BalanceOf<T>,
 			description: Vec<u8>,
-		) {
+		) -> DispatchResult {
 			let proposer = ensure_signed(origin)?;
 			Self::create_bounty(proposer, description, value)?;
+			Ok(())
 		}

 		/// Approve a bounty proposal. At a later time, the bounty will be funded and become active
@@ -317,8 +302,11 @@ decl_module! {
 		/// # <weight>
 		/// - O(1).
 		/// # </weight>
-		#[weight = <T as Config>::WeightInfo::approve_bounty()]
-		fn approve_bounty(origin, #[compact] bounty_id: BountyIndex) {
+		#[pallet::weight(<T as Config>::WeightInfo::approve_bounty())]
+		pub fn approve_bounty(
+			origin: OriginFor<T>,
+			#[pallet::compact] bounty_id: BountyIndex,
+		) -> DispatchResult {
 			T::ApproveOrigin::ensure_origin(origin)?;

 			Bounties::<T>::try_mutate_exists(bounty_id, |maybe_bounty| -> DispatchResult {
@@ -327,10 +315,11 @@ decl_module! {

 				bounty.status = BountyStatus::Approved;

-				BountyApprovals::append(bounty_id);
+				BountyApprovals::<T>::append(bounty_id);

 				Ok(())
 			})?;
+			Ok(())
 		}

 		/// Assign a curator to a funded bounty.
@@ -340,18 +329,17 @@ decl_module! {
 		/// # <weight>
 		/// - O(1).
 		/// # </weight>
-		#[weight = <T as Config>::WeightInfo::propose_curator()]
-		fn propose_curator(
-			origin,
-			#[compact] bounty_id: BountyIndex,
+		#[pallet::weight(<T as Config>::WeightInfo::propose_curator())]
+		pub fn propose_curator(
+			origin: OriginFor<T>,
+			#[pallet::compact] bounty_id: BountyIndex,
 			curator: <T::Lookup as StaticLookup>::Source,
-			#[compact] fee: BalanceOf<T>,
-		) {
+			#[pallet::compact] fee: BalanceOf<T>,
+		) -> DispatchResult {
 			T::ApproveOrigin::ensure_origin(origin)?;

 			let curator = T::Lookup::lookup(curator)?;
 			Bounties::<T>::try_mutate_exists(bounty_id, |maybe_bounty| -> DispatchResult {
-
 				let mut bounty = maybe_bounty.as_mut().ok_or(Error::<T>::InvalidIndex)?;
 				match bounty.status {
 					BountyStatus::Proposed | BountyStatus::Approved | BountyStatus::Funded => {},
@@ -365,14 +353,15 @@ decl_module! {

 				Ok(())
 			})?;
+			Ok(())
 		}

 		/// Unassign curator from a bounty.
 		///
 		/// This function can only be called by the `RejectOrigin` a signed origin.
 		///
-		/// If this function is called by the `RejectOrigin`, we assume that the curator is malicious
-		/// or inactive. As a result, we will slash the curator when possible.
+		/// If this function is called by the `RejectOrigin`, we assume that the curator is
+		/// malicious or inactive. As a result, we will slash the curator when possible.
 		///
 		/// If the origin is the curator, we take this as a sign they are unable to do their job and
 		/// they willingly give up. We could slash them, but for now we allow them to recover their
@@ -385,11 +374,11 @@ decl_module! {
 		/// # <weight>
 		/// - O(1).
 		/// # </weight>
-		#[weight = <T as Config>::WeightInfo::unassign_curator()]
-		fn unassign_curator(
-			origin,
-			#[compact] bounty_id: BountyIndex,
-		) {
+		#[pallet::weight(<T as Config>::WeightInfo::unassign_curator())]
+		pub fn unassign_curator(
+			origin: OriginFor<T>,
+			#[pallet::compact] bounty_id: BountyIndex,
+		) -> DispatchResult {
 			let maybe_sender = ensure_signed(origin.clone())
 				.map(Some)
 				.or_else(|_| T::RejectOrigin::ensure_origin(origin).map(|_| None))?;
@@ -407,7 +396,7 @@ decl_module! {
 					BountyStatus::Proposed | BountyStatus::Approved | BountyStatus::Funded => {
 						// No curator to unassign at this point.
 						return Err(Error::<T>::UnexpectedStatus.into())
-					}
+					},
 					BountyStatus::CuratorProposed { ref curator } => {
 						// A curator has been proposed, but not accepted yet.
 						// Either `RejectOrigin` or the proposed curator can unassign the curator.
@@ -425,7 +414,7 @@ decl_module! {
 								// If the sender is not the curator, and the curator is inactive,
 								// slash the curator.
 								if sender != *curator {
-									let block_number = system::Pallet::<T>::block_number();
+									let block_number = frame_system::Pallet::<T>::block_number();
 									if *update_due < block_number {
 										slash_curator(curator, &mut bounty.curator_deposit);
 									// Continue to change bounty status below...
@@ -436,7 +425,8 @@ decl_module! {
 								} else {
 									// Else this is the curator, willingly giving up their role.
 									// Give back their deposit.
-									let err_amount = T::Currency::unreserve(&curator, bounty.curator_deposit);
+									let err_amount =
+										T::Currency::unreserve(&curator, bounty.curator_deposit);
 									debug_assert!(err_amount.is_zero());
 									// Continue to change bounty status below...
 								}
@@ -450,12 +440,13 @@ decl_module! {
 						ensure!(maybe_sender.is_none(), BadOrigin);
 						slash_curator(curator, &mut bounty.curator_deposit);
 						// Continue to change bounty status below...
-					}
+					},
 				};

 				bounty.status = BountyStatus::Funded;
 				Ok(())
 			})?;
+			Ok(())
 		}

 		/// Accept the curator role for a bounty.
@@ -466,8 +457,11 @@ decl_module! {
 		/// # <weight>
 		/// - O(1).
 		/// # </weight>
-		#[weight = <T as Config>::WeightInfo::accept_curator()]
-		fn accept_curator(origin, #[compact] bounty_id: BountyIndex) {
+		#[pallet::weight(<T as Config>::WeightInfo::accept_curator())]
+		pub fn accept_curator(
+			origin: OriginFor<T>,
+			#[pallet::compact] bounty_id: BountyIndex,
+		) -> DispatchResult {
 			let signer = ensure_signed(origin)?;

 			Bounties::<T>::try_mutate_exists(bounty_id, |maybe_bounty| -> DispatchResult {
@@ -481,17 +475,21 @@ decl_module! {
 						T::Currency::reserve(curator, deposit)?;
 						bounty.curator_deposit = deposit;

-						let update_due = system::Pallet::<T>::block_number() + T::BountyUpdatePeriod::get();
-						bounty.status = BountyStatus::Active { curator: curator.clone(), update_due };
+						let update_due = frame_system::Pallet::<T>::block_number() +
+							T::BountyUpdatePeriod::get();
+						bounty.status =
+							BountyStatus::Active { curator: curator.clone(), update_due };

 						Ok(())
 					},
 					_ => Err(Error::<T>::UnexpectedStatus.into()),
 				}
 			})?;
+			Ok(())
 		}

-		/// Award bounty to a beneficiary account. The beneficiary will be able to claim the funds after a delay.
+		/// Award bounty to a beneficiary account. The beneficiary will be able to claim the funds
+		/// after a delay.
 		///
 		/// The dispatch origin for this call must be the curator of this bounty.
 		///
@@ -501,18 +499,19 @@ decl_module! {
 		/// # <weight>
 		/// - O(1).
 		/// # </weight>
-		#[weight = <T as Config>::WeightInfo::award_bounty()]
-		fn award_bounty(origin, #[compact] bounty_id: BountyIndex, beneficiary: <T::Lookup as StaticLookup>::Source) {
+		#[pallet::weight(<T as Config>::WeightInfo::award_bounty())]
+		pub fn award_bounty(
+			origin: OriginFor<T>,
+			#[pallet::compact] bounty_id: BountyIndex,
+			beneficiary: <T::Lookup as StaticLookup>::Source,
+		) -> DispatchResult {
 			let signer = ensure_signed(origin)?;
 			let beneficiary = T::Lookup::lookup(beneficiary)?;

 			Bounties::<T>::try_mutate_exists(bounty_id, |maybe_bounty| -> DispatchResult {
 				let mut bounty = maybe_bounty.as_mut().ok_or(Error::<T>::InvalidIndex)?;
 				match &bounty.status {
-					BountyStatus::Active {
-						curator,
-						..
-					} => {
+					BountyStatus::Active { curator, .. } => {
 						ensure!(signer == *curator, Error::<T>::RequireCurator);
 					},
 					_ => return Err(Error::<T>::UnexpectedStatus.into()),
@@ -520,13 +519,15 @@ decl_module! {
 				bounty.status = BountyStatus::PendingPayout {
 					curator: signer,
 					beneficiary: beneficiary.clone(),
-					unlock_at: system::Pallet::<T>::block_number() + T::BountyDepositPayoutDelay::get(),
+					unlock_at: frame_system::Pallet::<T>::block_number() +
+						T::BountyDepositPayoutDelay::get(),
 				};

 				Ok(())
 			})?;

 			Self::deposit_event(Event::<T>::BountyAwarded(bounty_id, beneficiary));
+			Ok(())
 		}

 		/// Claim the payout from an awarded bounty after payout delay.
@@ -538,14 +539,22 @@ decl_module! {
 		/// # <weight>
 		/// - O(1).
 		/// # </weight>
-		#[weight = <T as Config>::WeightInfo::claim_bounty()]
-		fn claim_bounty(origin, #[compact] bounty_id: BountyIndex) {
+		#[pallet::weight(<T as Config>::WeightInfo::claim_bounty())]
+		pub fn claim_bounty(
+			origin: OriginFor<T>,
+			#[pallet::compact] bounty_id: BountyIndex,
+		) -> DispatchResult {
 			let _ = ensure_signed(origin)?; // anyone can trigger claim

 			Bounties::<T>::try_mutate_exists(bounty_id, |maybe_bounty| -> DispatchResult {
 				let bounty = maybe_bounty.take().ok_or(Error::<T>::InvalidIndex)?;
-				if let BountyStatus::PendingPayout { curator, beneficiary, unlock_at } = bounty.status {
-					ensure!(system::Pallet::<T>::block_number() >= unlock_at, Error::<T>::Premature);
+				if let BountyStatus::PendingPayout { curator, beneficiary, unlock_at } =
+					bounty.status
+				{
+					ensure!(
+						frame_system::Pallet::<T>::block_number() >= unlock_at,
+						Error::<T>::Premature
+					);
 					let bounty_account = Self::bounty_account_id(bounty_id);
 					let balance = T::Currency::free_balance(&bounty_account);
 					let fee = bounty.fee.min(balance); // just to be safe
@@ -554,12 +563,13 @@ decl_module! {
 					debug_assert!(err_amount.is_zero());
 					let res = T::Currency::transfer(&bounty_account, &curator, fee, AllowDeath); // should not fail
 					debug_assert!(res.is_ok());
-					let res = T::Currency::transfer(&bounty_account, &beneficiary, payout, AllowDeath); // should not fail
+					let res =
+						T::Currency::transfer(&bounty_account, &beneficiary, payout, AllowDeath); // should not fail
 					debug_assert!(res.is_ok());

 					*maybe_bounty = None;

-					BountyDescriptions::remove(bounty_id);
+					BountyDescriptions::<T>::remove(bounty_id);

 					Self::deposit_event(Event::<T>::BountyClaimed(bounty_id, payout, beneficiary));
 					Ok(())
@@ -567,6 +577,7 @@ decl_module! {
 					Err(Error::<T>::UnexpectedStatus.into())
 				}
 			})?;
+			Ok(())
 		}

 		/// Cancel a proposed or active bounty. All the funds will be sent to treasury and
@@ -579,17 +590,23 @@ decl_module! {
 		/// # <weight>
 		/// - O(1).
 		/// # </weight>
-		#[weight = <T as Config>::WeightInfo::close_bounty_proposed().max(<T as Config>::WeightInfo::close_bounty_active())]
-		fn close_bounty(origin, #[compact] bounty_id: BountyIndex) -> DispatchResultWithPostInfo {
+		#[pallet::weight(<T as Config>::WeightInfo::close_bounty_proposed()
+			.max(<T as Config>::WeightInfo::close_bounty_active()))]
+		pub fn close_bounty(
+			origin: OriginFor<T>,
+			#[pallet::compact] bounty_id: BountyIndex,
+		) -> DispatchResultWithPostInfo {
 			T::RejectOrigin::ensure_origin(origin)?;

-			Bounties::<T>::try_mutate_exists(bounty_id, |maybe_bounty| -> DispatchResultWithPostInfo {
+			Bounties::<T>::try_mutate_exists(
+				bounty_id,
+				|maybe_bounty| -> DispatchResultWithPostInfo {
 					let bounty = maybe_bounty.as_ref().ok_or(Error::<T>::InvalidIndex)?;

 					match &bounty.status {
 						BountyStatus::Proposed => {
 							// The reject origin would like to cancel a proposed bounty.
-						BountyDescriptions::remove(bounty_id);
+							BountyDescriptions::<T>::remove(bounty_id);
 							let value = bounty.bond;
 							let imbalance = T::Currency::slash_reserved(&bounty.proposer, value).0;
 							T::OnSlash::on_unbalanced(imbalance);
@@ -597,20 +614,22 @@ decl_module! {

 							Self::deposit_event(Event::<T>::BountyRejected(bounty_id, value));
 							// Return early, nothing else to do.
-						return Ok(Some(<T as Config>::WeightInfo::close_bounty_proposed()).into())
+							return Ok(
+								Some(<T as Config>::WeightInfo::close_bounty_proposed()).into()
+							)
 						},
 						BountyStatus::Approved => {
 							// For weight reasons, we don't allow a council to cancel in this phase.
 							// We ask for them to wait until it is funded before they can cancel.
 							return Err(Error::<T>::UnexpectedStatus.into())
 						},
-					BountyStatus::Funded |
-					BountyStatus::CuratorProposed { .. } => {
+						BountyStatus::Funded | BountyStatus::CuratorProposed { .. } => {
 							// Nothing extra to do besides the removal of the bounty below.
 						},
 						BountyStatus::Active { curator, .. } => {
 							// Cancelled by council, refund deposit of the working curator.
-						let err_amount = T::Currency::unreserve(&curator, bounty.curator_deposit);
+							let err_amount =
+								T::Currency::unreserve(&curator, bounty.curator_deposit);
 							debug_assert!(err_amount.is_zero());
 							// Then execute removal of the bounty below.
 						},
@@ -620,21 +639,27 @@ decl_module! {
 							// So the council should first unassign the curator, slashing their
 							// deposit.
 							return Err(Error::<T>::PendingPayout.into())
-					}
+						},
 					}

 					let bounty_account = Self::bounty_account_id(bounty_id);

-				BountyDescriptions::remove(bounty_id);
+					BountyDescriptions::<T>::remove(bounty_id);

 					let balance = T::Currency::free_balance(&bounty_account);
-				let res = T::Currency::transfer(&bounty_account, &Self::account_id(), balance, AllowDeath); // should not fail
+					let res = T::Currency::transfer(
+						&bounty_account,
+						&Self::account_id(),
+						balance,
+						AllowDeath,
+					); // should not fail
 					debug_assert!(res.is_ok());
 					*maybe_bounty = None;

 					Self::deposit_event(Event::<T>::BountyCanceled(bounty_id));
 					Ok(Some(<T as Config>::WeightInfo::close_bounty_active()).into())
-			})
+				},
+			)
 		}

 		/// Extend the expiry time of an active bounty.
@@ -647,8 +672,12 @@ decl_module! {
 		/// # <weight>
 		/// - O(1).
 		/// # </weight>
-		#[weight = <T as Config>::WeightInfo::extend_bounty_expiry()]
-		fn extend_bounty_expiry(origin, #[compact] bounty_id: BountyIndex, _remark: Vec<u8>) {
+		#[pallet::weight(<T as Config>::WeightInfo::extend_bounty_expiry())]
+		pub fn extend_bounty_expiry(
+			origin: OriginFor<T>,
+			#[pallet::compact] bounty_id: BountyIndex,
+			_remark: Vec<u8>,
+		) -> DispatchResult {
 			let signer = ensure_signed(origin)?;

 			Bounties::<T>::try_mutate_exists(bounty_id, |maybe_bounty| -> DispatchResult {
@@ -657,7 +686,9 @@ decl_module! {
 				match bounty.status {
 					BountyStatus::Active { ref curator, ref mut update_due } => {
 						ensure!(*curator == signer, Error::<T>::RequireCurator);
-						*update_due = (system::Pallet::<T>::block_number() + T::BountyUpdatePeriod::get()).max(*update_due);
+						*update_due = (frame_system::Pallet::<T>::block_number() +
+							T::BountyUpdatePeriod::get())
+						.max(*update_due);
 					},
 					_ => return Err(Error::<T>::UnexpectedStatus.into()),
 				}
@@ -666,11 +697,12 @@ decl_module! {
 			})?;

 			Self::deposit_event(Event::<T>::BountyExtended(bounty_id));
+			Ok(())
 		}
 	}
 }

-impl<T: Config> Module<T> {
+impl<T: Config> Pallet<T> {
 	// Add public immutables and private mutables.

 	/// The account ID of the treasury pot.
@@ -707,7 +739,7 @@ impl<T: Config> Module<T> {
 		T::Currency::reserve(&proposer, bond)
 			.map_err(|_| Error::<T>::InsufficientProposersBalance)?;

-		BountyCount::put(index + 1);
+		BountyCount::<T>::put(index + 1);

 		let bounty = Bounty {
 			proposer,
@@ -719,22 +751,22 @@ impl<T: Config> Module<T> {
 		};

 		Bounties::<T>::insert(index, &bounty);
-		BountyDescriptions::insert(index, description);
+		BountyDescriptions::<T>::insert(index, description);

-		Self::deposit_event(RawEvent::BountyProposed(index));
+		Self::deposit_event(Event::<T>::BountyProposed(index));

 		Ok(())
 	}
 }

-impl<T: Config> pallet_treasury::SpendFunds<T> for Module<T> {
+impl<T: Config> pallet_treasury::SpendFunds<T> for Pallet<T> {
 	fn spend_funds(
 		budget_remaining: &mut BalanceOf<T>,
 		imbalance: &mut PositiveImbalanceOf<T>,
 		total_weight: &mut Weight,
 		missed_any: &mut bool,
 	) {
-		let bounties_len = BountyApprovals::mutate(|v| {
+		let bounties_len = BountyApprovals::<T>::mutate(|v| {
 			let bounties_approval_len = v.len() as u32;
 			v.retain(|&index| {
 				Bounties::<T>::mutate(index, |bounty| {
@@ -755,7 +787,7 @@ impl<T: Config> pallet_treasury::SpendFunds<T> for Module<T> {
 								bounty.value,
 							));

-							Self::deposit_event(RawEvent::BountyBecameActive(index));
+							Self::deposit_event(Event::<T>::BountyBecameActive(index));
 							false
 						} else {
 							*missed_any = true;
@@ -0,0 +1,19 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2019-2021 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.
+
+/// Version 4.
+pub mod v4;
@@ -0,0 +1,230 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2019-2021 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.
+
+use frame_support::{
+	storage::{generator::StorageValue, StoragePrefixedMap},
+	traits::{
+		Get, GetStorageVersion, PalletInfoAccess, StorageVersion,
+		STORAGE_VERSION_STORAGE_KEY_POSTFIX,
+	},
+	weights::Weight,
+};
+use sp_core::hexdisplay::HexDisplay;
+use sp_io::{hashing::twox_128, storage};
+use sp_std::str;
+
+use crate as pallet_bounties;
+
+/// Migrate the storage of the bounties pallet to a new prefix, leaving all other storage untouched
+///
+/// This new prefix must be the same as the one set in construct_runtime. For safety, use
+/// `PalletInfo` to get it, as:
+/// `<Runtime as frame_system::Config>::PalletInfo::name::<BountiesPallet>`.
+///
+/// The migration will look into the storage version in order not to trigger a migration on an up
+/// to date storage. Thus the on chain storage version must be less than 4 in order to trigger the
+/// migration.
+pub fn migrate<
+	T: pallet_bounties::Config,
+	P: GetStorageVersion + PalletInfoAccess,
+	N: AsRef<str>,
+>(
+	old_pallet_name: N,
+	new_pallet_name: N,
+) -> Weight {
+	let old_pallet_name = old_pallet_name.as_ref();
+	let new_pallet_name = new_pallet_name.as_ref();
+
+	if new_pallet_name == old_pallet_name {
+		log::info!(
+			target: "runtime::bounties",
+			"New pallet name is equal to the old prefix. No migration needs to be done.",
+		);
+		return 0
+	}
+
+	let on_chain_storage_version = <P as GetStorageVersion>::on_chain_storage_version();
+	log::info!(
+		target: "runtime::bounties",
+		"Running migration to v4 for bounties with storage version {:?}",
+		on_chain_storage_version,
+	);
+
+	if on_chain_storage_version < 4 {
+		let storage_prefix = pallet_bounties::BountyCount::<T>::storage_prefix();
+		frame_support::storage::migration::move_storage_from_pallet(
+			storage_prefix,
+			old_pallet_name.as_bytes(),
+			new_pallet_name.as_bytes(),
+		);
+		log_migration("migration", storage_prefix, old_pallet_name, new_pallet_name);
+
+		let storage_prefix = pallet_bounties::Bounties::<T>::storage_prefix();
+		frame_support::storage::migration::move_storage_from_pallet(
+			storage_prefix,
+			old_pallet_name.as_bytes(),
+			new_pallet_name.as_bytes(),
+		);
+		log_migration("migration", storage_prefix, old_pallet_name, new_pallet_name);
+
+		let storage_prefix = pallet_bounties::BountyDescriptions::<T>::storage_prefix();
+		frame_support::storage::migration::move_storage_from_pallet(
+			storage_prefix,
+			old_pallet_name.as_bytes(),
+			new_pallet_name.as_bytes(),
+		);
+		log_migration("migration", storage_prefix, old_pallet_name, new_pallet_name);
+
+		let storage_prefix = pallet_bounties::BountyApprovals::<T>::storage_prefix();
+		frame_support::storage::migration::move_storage_from_pallet(
+			storage_prefix,
+			old_pallet_name.as_bytes(),
+			new_pallet_name.as_bytes(),
+		);
+		log_migration("migration", storage_prefix, old_pallet_name, new_pallet_name);
+
+		StorageVersion::new(4).put::<P>();
+		<T as frame_system::Config>::BlockWeights::get().max_block
+	} else {
+		log::warn!(
+			target: "runtime::bounties",
+			"Attempted to apply migration to v4 but failed because storage version is {:?}",
+			on_chain_storage_version,
+		);
+		0
+	}
+}
+
+/// Some checks prior to migration. This can be linked to
+/// [`frame_support::traits::OnRuntimeUpgrade::pre_upgrade`] for further testing.
+///
+/// Panics if anything goes wrong.
+pub fn pre_migration<T: pallet_bounties::Config, P: GetStorageVersion + 'static, N: AsRef<str>>(
+	old_pallet_name: N,
+	new_pallet_name: N,
+) {
+	let old_pallet_name = old_pallet_name.as_ref();
+	let new_pallet_name = new_pallet_name.as_ref();
+	let storage_prefix_bounties_count = pallet_bounties::BountyCount::<T>::storage_prefix();
+	let storage_prefix_bounties = pallet_bounties::Bounties::<T>::storage_prefix();
+	let storage_prefix_bounties_description =
+		pallet_bounties::BountyDescriptions::<T>::storage_prefix();
+	let storage_prefix_bounties_approvals = pallet_bounties::BountyApprovals::<T>::storage_prefix();
+	log_migration("pre-migration", storage_prefix_bounties_count, old_pallet_name, new_pallet_name);
+	log_migration("pre-migration", storage_prefix_bounties, old_pallet_name, new_pallet_name);
+	log_migration(
+		"pre-migration",
+		storage_prefix_bounties_description,
+		old_pallet_name,
+		new_pallet_name,
+	);
+	log_migration(
+		"pre-migration",
+		storage_prefix_bounties_approvals,
+		old_pallet_name,
+		new_pallet_name,
+	);
+
+	let new_pallet_prefix = twox_128(new_pallet_name.as_bytes());
+	let storage_version_key =
+		[&new_pallet_prefix, &twox_128(STORAGE_VERSION_STORAGE_KEY_POSTFIX)[..]].concat();
+
+	// ensure nothing is stored in the new prefix.
+	assert!(
+		storage::next_key(&new_pallet_prefix).map_or(
+			// either nothing is there
+			true,
+			// or we ensure that the next key has no common prefix with twox_128(new),
+			// or is the pallet version that is already stored using the pallet name
+			|next_key| {
+				storage::next_key(&next_key).map_or(true, |next_key| {
+					!next_key.starts_with(&new_pallet_prefix) || next_key == storage_version_key
+				})
+			},
+		),
+		"unexpected next_key({}) = {:?}",
+		new_pallet_name,
+		HexDisplay::from(&sp_io::storage::next_key(&new_pallet_prefix).unwrap()),
+	);
+	assert!(<P as GetStorageVersion>::on_chain_storage_version() < 4);
+}
+
+/// Some checks for after migration. This can be linked to
+/// [`frame_support::traits::OnRuntimeUpgrade::post_upgrade`] for further testing.
+///
+/// Panics if anything goes wrong.
+pub fn post_migration<T: pallet_bounties::Config, P: GetStorageVersion, N: AsRef<str>>(
+	old_pallet_name: N,
+	new_pallet_name: N,
+) {
+	let old_pallet_name = old_pallet_name.as_ref();
+	let new_pallet_name = new_pallet_name.as_ref();
+	let storage_prefix_bounties_count = pallet_bounties::BountyCount::<T>::storage_prefix();
+	let storage_prefix_bounties = pallet_bounties::Bounties::<T>::storage_prefix();
+	let storage_prefix_bounties_description =
+		pallet_bounties::BountyDescriptions::<T>::storage_prefix();
+	let storage_prefix_bounties_approvals = pallet_bounties::BountyApprovals::<T>::storage_prefix();
+	log_migration(
+		"post-migration",
+		storage_prefix_bounties_count,
+		old_pallet_name,
+		new_pallet_name,
+	);
+	log_migration("post-migration", storage_prefix_bounties, old_pallet_name, new_pallet_name);
+	log_migration(
+		"post-migration",
+		storage_prefix_bounties_description,
+		old_pallet_name,
+		new_pallet_name,
+	);
+	log_migration(
+		"post-migration",
+		storage_prefix_bounties_approvals,
+		old_pallet_name,
+		new_pallet_name,
+	);
+
+	let old_pallet_prefix = twox_128(old_pallet_name.as_bytes());
+	let old_bounties_count_key =
+		[&old_pallet_prefix, &twox_128(storage_prefix_bounties_count)[..]].concat();
+	let old_bounties_key = [&old_pallet_prefix, &twox_128(storage_prefix_bounties)[..]].concat();
+	let old_bounties_description_key =
+		[&old_pallet_prefix, &twox_128(storage_prefix_bounties_description)[..]].concat();
+	let old_bounties_approvals_key =
+		[&old_pallet_prefix, &twox_128(storage_prefix_bounties_approvals)[..]].concat();
+	assert!(storage::next_key(&old_bounties_count_key)
+		.map_or(true, |next_key| !next_key.starts_with(&old_bounties_count_key)));
+	assert!(storage::next_key(&old_bounties_key)
+		.map_or(true, |next_key| !next_key.starts_with(&old_bounties_key)));
+	assert!(storage::next_key(&old_bounties_description_key)
+		.map_or(true, |next_key| !next_key.starts_with(&old_bounties_description_key)));
+	assert!(storage::next_key(&old_bounties_approvals_key)
+		.map_or(true, |next_key| !next_key.starts_with(&old_bounties_approvals_key)));
+
+	assert_eq!(<P as GetStorageVersion>::on_chain_storage_version(), 4);
+}
+
+fn log_migration(stage: &str, storage_prefix: &[u8], old_pallet_name: &str, new_pallet_name: &str) {
+	log::info!(
+		target: "runtime::bounties",
+		"{} prefix of storage '{}': '{}' ==> '{}'",
+		stage,
+		str::from_utf8(storage_prefix).unwrap_or("<Invalid UTF8>"),
+		old_pallet_name,
+		new_pallet_name,
+	);
+}
@@ -32,9 +32,11 @@ use sp_core::H256;
 use sp_runtime::{
 	testing::Header,
 	traits::{BadOrigin, BlakeTwo256, IdentityLookup},
-	Perbill,
+	Perbill, Storage,
 };

+use super::Event as BountiesEvent;
+
 type UncheckedExtrinsic = frame_system::mocking::MockUncheckedExtrinsic<Test>;
 type Block = frame_system::mocking::MockBlock<Test>;

@@ -160,7 +162,7 @@ pub fn new_test_ext() -> sp_io::TestExternalities {
 	t.into()
 }

-fn last_event() -> RawEvent<u64, u128> {
+fn last_event() -> BountiesEvent<Test> {
 	System::events()
 		.into_iter()
 		.map(|r| r.event)
@@ -396,7 +398,7 @@ fn propose_bounty_works() {

 		assert_ok!(Bounties::propose_bounty(Origin::signed(0), 10, b"1234567890".to_vec()));

-		assert_eq!(last_event(), RawEvent::BountyProposed(0));
+		assert_eq!(last_event(), BountiesEvent::BountyProposed(0));

 		let deposit: u64 = 85 + 5;
 		assert_eq!(Balances::reserved_balance(0), deposit);
@@ -458,7 +460,7 @@ fn close_bounty_works() {

 		let deposit: u64 = 80 + 5;

-		assert_eq!(last_event(), RawEvent::BountyRejected(0, deposit));
+		assert_eq!(last_event(), BountiesEvent::BountyRejected(0, deposit));

 		assert_eq!(Balances::reserved_balance(0), 0);
 		assert_eq!(Balances::free_balance(0), 100 - deposit);
@@ -690,7 +692,7 @@ fn award_and_claim_bounty_works() {

 		assert_ok!(Bounties::claim_bounty(Origin::signed(1), 0));

-		assert_eq!(last_event(), RawEvent::BountyClaimed(0, 56, 3));
+		assert_eq!(last_event(), BountiesEvent::BountyClaimed(0, 56, 3));

 		assert_eq!(Balances::free_balance(4), 14); // initial 10 + fee 4

@@ -729,7 +731,7 @@ fn claim_handles_high_fee() {

 		assert_ok!(Bounties::claim_bounty(Origin::signed(1), 0));

-		assert_eq!(last_event(), RawEvent::BountyClaimed(0, 0, 3));
+		assert_eq!(last_event(), BountiesEvent::BountyClaimed(0, 0, 3));

 		assert_eq!(Balances::free_balance(4), 70); // 30 + 50 - 10
 		assert_eq!(Balances::free_balance(3), 0);
@@ -806,7 +808,7 @@ fn award_and_cancel() {
 		assert_ok!(Bounties::unassign_curator(Origin::root(), 0));
 		assert_ok!(Bounties::close_bounty(Origin::root(), 0));

-		assert_eq!(last_event(), RawEvent::BountyCanceled(0));
+		assert_eq!(last_event(), BountiesEvent::BountyCanceled(0));

 		assert_eq!(Balances::free_balance(Bounties::bounty_account_id(0)), 0);

@@ -934,6 +936,48 @@ fn extend_expiry() {
 	});
 }

+#[test]
+fn test_migration_v4() {
+	let mut s = Storage::default();
+
+	let index: u32 = 10;
+
+	let bounty = Bounty::<u128, u64, u64> {
+		proposer: 0,
+		value: 20,
+		fee: 20,
+		curator_deposit: 20,
+		bond: 50,
+		status: BountyStatus::<u128, u64>::Proposed,
+	};
+
+	let data = vec![
+		(pallet_bounties::BountyCount::<Test>::hashed_key().to_vec(), 10.encode().to_vec()),
+		(pallet_bounties::Bounties::<Test>::hashed_key_for(index), bounty.encode().to_vec()),
+		(pallet_bounties::BountyDescriptions::<Test>::hashed_key_for(index), vec![0, 0]),
+		(
+			pallet_bounties::BountyApprovals::<Test>::hashed_key().to_vec(),
+			vec![10 as u32].encode().to_vec(),
+		),
+	];
+
+	s.top = data.into_iter().collect();
+
+	sp_io::TestExternalities::new(s).execute_with(|| {
+		use frame_support::traits::PalletInfo;
+		let old_pallet_name = <Test as frame_system::Config>::PalletInfo::name::<Bounties>()
+			.expect("Bounties is part of runtime, so it has a name; qed");
+		let new_pallet_name = "NewBounties";
+
+		crate::migrations::v4::pre_migration::<Test, Bounties, _>(old_pallet_name, new_pallet_name);
+		crate::migrations::v4::migrate::<Test, Bounties, _>(old_pallet_name, new_pallet_name);
+		crate::migrations::v4::post_migration::<Test, Bounties, _>(
+			old_pallet_name,
+			new_pallet_name,
+		);
+	});
+}
+
 #[test]
 fn genesis_funding_works() {
 	let mut t = frame_system::GenesisConfig::default().build_storage::<Test>().unwrap();