Add child-bounties pallet.

Cargo.toml

@@ -74,6 +74,7 @@ members = [
 	"frame/beefy-mmr/primitives",
 	"frame/benchmarking",
 	"frame/bounties",
+	"frame/child-bounties",
 	"frame/collective",
 	"frame/contracts",
 	"frame/contracts/rpc",

bin/node/runtime/Cargo.toml

@@ -59,6 +59,7 @@ pallet-babe = { version = "4.0.0-dev", default-features = false, path = "../../.
 pallet-bags-list = { version = "4.0.0-dev", default-features = false, path = "../../../frame/bags-list" }
 pallet-balances = { version = "4.0.0-dev", default-features = false, path = "../../../frame/balances" }
 pallet-bounties = { version = "4.0.0-dev", default-features = false, path = "../../../frame/bounties" }
+pallet-child-bounties = { version = "4.0.0-dev", default-features = false, path = "../../../frame/child-bounties" }
 pallet-collective = { version = "4.0.0-dev", default-features = false, path = "../../../frame/collective" }
 pallet-contracts = { version = "4.0.0-dev", default-features = false, path = "../../../frame/contracts" }
 pallet-contracts-primitives = { version = "4.0.0-dev", default-features = false, path = "../../../frame/contracts/common/" }
@@ -172,7 +173,8 @@ std = [
 	"log/std",
 	"frame-try-runtime/std",
 	"sp-npos-elections/std",
-  "sp-io/std"
+  	"sp-io/std",
+	"pallet-child-bounties/std",
 ]
 runtime-benchmarks = [
 	"frame-benchmarking",
@@ -185,6 +187,7 @@ runtime-benchmarks = [
 	"pallet-bags-list/runtime-benchmarks",
 	"pallet-balances/runtime-benchmarks",
 	"pallet-bounties/runtime-benchmarks",
+	"pallet-child-bounties/runtime-benchmarks",
 	"pallet-collective/runtime-benchmarks",
 	"pallet-contracts/runtime-benchmarks",
 	"pallet-democracy/runtime-benchmarks",
@@ -224,6 +227,7 @@ try-runtime = [
 	"pallet-babe/try-runtime",
 	"pallet-balances/try-runtime",
 	"pallet-bounties/try-runtime",
+	"pallet-child-bounties/try-runtime",
 	"pallet-collective/try-runtime",
 	"pallet-contracts/try-runtime",
 	"pallet-democracy/try-runtime",

bin/node/runtime/src/lib.rs

@@ -836,6 +836,8 @@ parameter_types! {
 	pub const BountyCuratorDeposit: Permill = Permill::from_percent(50);
 	pub const BountyValueMinimum: Balance = 5 * DOLLARS;
 	pub const MaxApprovals: u32 = 100;
+	pub const MaxActiveChildBountyCount: u32 = 5;
+	pub const ChildBountyValueMinimum: Balance = 1 * DOLLARS;
 }
 
 impl pallet_treasury::Config for Runtime {
@@ -873,6 +875,14 @@ impl pallet_bounties::Config for Runtime {
 	type DataDepositPerByte = DataDepositPerByte;
 	type MaximumReasonLength = MaximumReasonLength;
 	type WeightInfo = pallet_bounties::weights::SubstrateWeight<Runtime>;
+	type ChildBountyManager = ChildBounties;
+}
+
+impl pallet_child_bounties::Config for Runtime {
+	type Event = Event;
+	type MaxActiveChildBountyCount = MaxActiveChildBountyCount;
+	type ChildBountyValueMinimum = ChildBountyValueMinimum;
+	type WeightInfo = pallet_child_bounties::weights::SubstrateWeight<Runtime>;
 }
 
 impl pallet_tips::Config for Runtime {
@@ -1290,6 +1300,7 @@ construct_runtime!(
 		Uniques: pallet_uniques,
 		TransactionStorage: pallet_transaction_storage,
 		BagsList: pallet_bags_list,
+		ChildBounties: pallet_child_bounties,
 	}
 );
 
@@ -1629,6 +1640,7 @@ impl_runtime_apis! {
 			list_benchmark!(list, extra, pallet_bags_list, BagsList);
 			list_benchmark!(list, extra, pallet_balances, Balances);
 			list_benchmark!(list, extra, pallet_bounties, Bounties);
+			list_benchmark!(list, extra, pallet_child_bounties, ChildBounties);
 			list_benchmark!(list, extra, pallet_collective, Council);
 			list_benchmark!(list, extra, pallet_contracts, Contracts);
 			list_benchmark!(list, extra, pallet_democracy, Democracy);
@@ -1706,6 +1718,7 @@ impl_runtime_apis! {
 			add_benchmark!(params, batches, pallet_balances, Balances);
 			add_benchmark!(params, batches, pallet_bags_list, BagsList);
 			add_benchmark!(params, batches, pallet_bounties, Bounties);
+			add_benchmark!(params, batches, pallet_child_bounties, ChildBounties);
 			add_benchmark!(params, batches, pallet_collective, Council);
 			add_benchmark!(params, batches, pallet_contracts, Contracts);
 			add_benchmark!(params, batches, pallet_democracy, Democracy);

frame/bounties/src/lib.rs

@@ -123,6 +123,17 @@ pub struct Bounty<AccountId, Balance, BlockNumber> {
 	status: BountyStatus<AccountId, BlockNumber>,
 }
 
+// Getter for bounty status, to be used for child bounties.
+impl<
+	AccountId: PartialEq + Clone + Ord + Default,
+	Balance, 
+	BlockNumber: Clone
+	> Bounty<AccountId, Balance, BlockNumber> {
+	pub fn get_status(&self) -> BountyStatus<AccountId, BlockNumber> {
+		self.status.clone()
+	}
+}
+
 /// The status of a bounty proposal.
 #[derive(Encode, Decode, Clone, PartialEq, Eq, RuntimeDebug, TypeInfo)]
 pub enum BountyStatus<AccountId, BlockNumber> {
@@ -156,6 +167,15 @@ pub enum BountyStatus<AccountId, BlockNumber> {
 	},
 }
 
+/// The child-bounty manager.
+pub trait ChildBountyManager<Balance> {
+	/// Get the active child-bounties for a parent bounty.
+	fn child_bounties_count(bounty_id: BountyIndex) -> BountyIndex;
+
+	/// Get total curator fees of children-bounty curators.
+	fn children_curator_fees(bounty_id: BountyIndex) -> Balance;
+}
+
 #[frame_support::pallet]
 pub mod pallet {
 	use super::*;
@@ -200,6 +220,9 @@ pub mod pallet {
 
 		/// Weight information for extrinsics in this pallet.
 		type WeightInfo: WeightInfo;
+
+		/// The child-bounty manager.
+		type ChildBountyManager: ChildBountyManager<BalanceOf<Self>>;
 	}
 
 	#[pallet::error]
@@ -223,6 +246,8 @@ pub mod pallet {
 		PendingPayout,
 		/// The bounties cannot be claimed/closed because it's still in the countdown period.
 		Premature,
+		/// The bounty cannot be closed because it has active child-bounties.
+		RequireNoActiveChildBounty
 	}
 
 	#[pallet::event]
@@ -510,6 +535,11 @@ pub mod pallet {
 
 			Bounties::<T>::try_mutate_exists(bounty_id, |maybe_bounty| -> DispatchResult {
 				let mut bounty = maybe_bounty.as_mut().ok_or(Error::<T>::InvalidIndex)?;
+
+				// Ensure no active child-bounties before processing the call.
+				ensure!(T::ChildBountyManager::child_bounties_count(bounty_id) == 0, 
+					Error::<T>::RequireNoActiveChildBounty);
+
 				match &bounty.status {
 					BountyStatus::Active { curator, .. } => {
 						ensure!(signer == *curator, Error::<T>::RequireCurator);
@@ -561,7 +591,13 @@ pub mod pallet {
 					let payout = balance.saturating_sub(fee);
 					let err_amount = T::Currency::unreserve(&curator, bounty.curator_deposit);
 					debug_assert!(err_amount.is_zero());
-					let res = T::Currency::transfer(&bounty_account, &curator, fee, AllowDeath); // should not fail
+
+					// Get total child-bounties curator fees, and subtract it from master curator fee.
+					let children_fee = T::ChildBountyManager::children_curator_fees(bounty_id);
+					debug_assert!(children_fee <= fee);
+
+					let final_fee = fee.saturating_sub(children_fee);
+					let res = T::Currency::transfer(&bounty_account, &curator, final_fee, AllowDeath); // should not fail
 					debug_assert!(res.is_ok());
 					let res =
 						T::Currency::transfer(&bounty_account, &beneficiary, payout, AllowDeath); // should not fail
@@ -607,6 +643,10 @@ pub mod pallet {
 				|maybe_bounty| -> DispatchResultWithPostInfo {
 					let bounty = maybe_bounty.as_ref().ok_or(Error::<T>::InvalidIndex)?;
 
+					// Ensure no active child-bounties before processing the call.
+					ensure!(T::ChildBountyManager::child_bounties_count(bounty_id) == 0, 
+						Error::<T>::RequireNoActiveChildBounty);
+
 					match &bounty.status {
 						BountyStatus::Proposed => {
 							// The reject origin would like to cancel a proposed bounty.
@@ -811,3 +851,14 @@ impl<T: Config> pallet_treasury::SpendFunds<T> for Pallet<T> {
 		*total_weight += <T as Config>::WeightInfo::spend_funds(bounties_len);
 	}
 }
+
+// Default impl for when ChildBounties is not being used in the runtime.
+impl<Balance: Zero> ChildBountyManager<Balance> for () {
+	fn child_bounties_count(_bounty_id: BountyIndex) -> BountyIndex {
+		Default::default()
+	}
+
+	fn children_curator_fees(_bounty_id: BountyIndex) -> Balance {
+		Zero::zero()
+	}
+}

frame/bounties/src/tests.rs

@@ -146,6 +146,7 @@ impl Config for Test {
 	type DataDepositPerByte = DataDepositPerByte;
 	type MaximumReasonLength = MaximumReasonLength;
 	type WeightInfo = ();
+	type ChildBountyManager = ();
 }
 
 type TreasuryError = pallet_treasury::Error<Test>;

frame/child-bounties/Cargo.toml

@@ -0,0 +1,54 @@
+[package]
+name = "pallet-child-bounties"
+version = "4.0.0-dev"
+authors = ["Parity Technologies <admin@parity.io>"]
+edition = "2021"
+license = "Apache-2.0"
+homepage = "https://substrate.io"
+repository = "https://github.com/paritytech/substrate/"
+description = "FRAME pallet to manage child bounties"
+readme = "README.md"
+
+[package.metadata.docs.rs]
+targets = ["x86_64-unknown-linux-gnu"]
+
+[dependencies]
+codec = { package = "parity-scale-codec", version = "2.0.0", default-features = false, features = [
+	"derive",
+] }
+scale-info = { version = "1.0", default-features = false, features = ["derive"] }
+sp-std = { version = "4.0.0-dev", default-features = false, path = "../../primitives/std" }
+sp-runtime = { version = "4.0.0-dev", default-features = false, path = "../../primitives/runtime" }
+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" }
+pallet-bounties = { version = "4.0.0-dev", default-features = false, path = "../bounties" }
+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]
+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",
+	"pallet-bounties/std",
+	"log/std",
+]
+runtime-benchmarks = [
+	"frame-benchmarking",
+	"frame-support/runtime-benchmarks",
+	"frame-system/runtime-benchmarks",
+]
+try-runtime = ["frame-support/try-runtime"]

frame/child-bounties/README.md

@@ -0,0 +1,21 @@
+# Child Bounties Pallet (pallet-child-bounties)
+
+## Child Bounty
+
+> NOTE: This pallet is tightly coupled with pallet-treasury and pallet-bounties.
+
+With child bounties, a large bounty proposal can be divided into smaller chunks, for parallel execution, and for efficient governance and tracking of spent funds.
+
+A child-bounty is a smaller piece of work, extracted from a parent bounty. A curator is assigned after the child-bounty is created by the parent bounty curator, to be delegated with the responsibility of assigning a payout address once the specified set of tasks is completed.
+
+## Interface
+
+### Dispatchable Functions
+
+- `add_child_bounty` - Add a child-bounty for a parent-bounty to for dividing the work in smaller tasks.
+- `propose_curator` - Assign an account to a child-bounty as candidate curator.
+- `accept_curator` - Accept a child-bounty assignment from the parent-bounty curator, setting a curator deposit.
+- `award_child_bounty` - Close and pay out the specified amount for the completed work.
+- `claim_child_bounty` - Claim a specific child-bounty amount from the payout address.
+- `unassign_curator` - Unassign an accepted curator from a specific child-bounty.
+- `close_child_bounty` - Cancel the child-bounty for a specific treasury amount and close the bounty.