Collective: dynamic deposit based on number of proposals (#3151)

Introduce a dynamic proposal deposit mechanism influenced by the total
number of active proposals, with the option to set the deposit to none.

The potential cost (e.g., balance hold) for proposal submission and
storage is determined by the implementation of the `Consideration`
trait. The footprint is defined as `proposal_count`, representing the
total number of active proposals in the system, excluding the one
currently being proposed. This cost may vary based on the proposal
count. The pallet also offers various types to define a cost strategy
based on the number of proposals.

Two new calls are introduced:
- kill(origin, proposal_hash): the cancellation of a proposal,
accompanied by the burning of the associated cost/consideration ticket.
- release_proposal_cost(origin, proposal_hash): the release of the cost
for a non-active proposal.

Additionally change: 
- benchmarks have been upgraded to benchmarks::v2 for collective pallet;
- `ensure_successful` function added to the `Consideration` under
`runtime-benchmarks` feature.

---------

Co-authored-by: command-bot <>
Co-authored-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>
Co-authored-by: GitHub Action <action@github.com>

cumulus/parachains/runtimes/collectives/collectives-westend/src/lib.rs

@@ -552,6 +552,9 @@ impl pallet_collective::Config<AllianceCollective> for Runtime {
 	type SetMembersOrigin = EnsureRoot<AccountId>;
 	type WeightInfo = weights::pallet_collective::WeightInfo<Runtime>;
 	type MaxProposalWeight = MaxProposalWeight;
+	type DisapproveOrigin = EnsureRoot<Self::AccountId>;
+	type KillOrigin = EnsureRoot<Self::AccountId>;
+	type Consideration = ();
 }
 
 pub const MAX_FELLOWS: u32 = ALLIANCE_MAX_MEMBERS;

prdoc/pr_3151.prdoc

@@ -0,0 +1,49 @@
+# Schema: Polkadot SDK PRDoc Schema (prdoc) v1.0.0
+# See doc at https://raw.githubusercontent.com/paritytech/polkadot-sdk/master/prdoc/schema_user.json
+
+title: Dynamic deposit based on number of proposals 
+
+doc:
+  - audience: 
+      - Runtime User
+      - Runtime Dev
+    description: |
+      Introduce a dynamic proposal deposit mechanism influenced by the total number of active 
+      proposals, with the option to set the deposit to none.
+
+      The potential cost (e.g., balance hold) for proposal submission and storage is determined 
+      by the implementation of the `Consideration` trait. The footprint is defined as `proposal_count`, 
+      representing the total number of active proposals in the system, excluding the one currently 
+      being proposed. This cost may vary based on the proposal count. The pallet also offers various 
+      types to define a cost strategy based on the number of proposals.
+
+      Two new calls are introduced:
+        - kill(origin, proposal_hash): the cancellation of a proposal, accompanied by the burning 
+        of the associated cost/consideration ticket.
+        - release_proposal_cost(origin, proposal_hash): the release of the cost for a non-active proposal.
+
+      New config parameters:
+        - DisapproveOrigin: origin from which a proposal in any status may be disapproved without 
+        associated cost for a proposer;
+        - KillOrigin: Origin from which any malicious proposal may be killed with associated cost 
+        for a proposer;
+        - Consideration: mechanism to assess the necessity of some cost for publishing and storing 
+        a proposal. Set to unit type to have not submission cost;
+
+      Additionally change: 
+        - benchmarks have been upgraded to benchmarks::v2 for collective pallet;
+        - `ensure_successful` function added to the `Consideration` under `runtime-benchmarks` feature.
+
+crates:
+  - name: pallet-collective
+    bump: major
+  - name: collectives-westend-runtime
+    bump: major
+  - name: kitchensink-runtime
+    bump: major
+  - name: pallet-alliance
+    bump: patch
+  - name: pallet-balances
+    bump: patch
+  - name: pallet-utility
+    bump: patch

substrate/bin/node/runtime/src/lib.rs

@@ -1114,6 +1114,9 @@ parameter_types! {
 	pub const CouncilMotionDuration: BlockNumber = 5 * DAYS;
 	pub const CouncilMaxProposals: u32 = 100;
 	pub const CouncilMaxMembers: u32 = 100;
+	pub const ProposalDepositOffset: Balance = ExistentialDeposit::get() + ExistentialDeposit::get();
+	pub const ProposalHoldReason: RuntimeHoldReason =
+		RuntimeHoldReason::Council(pallet_collective::HoldReason::ProposalSubmission);
 }
 
 type CouncilCollective = pallet_collective::Instance1;
@@ -1128,6 +1131,18 @@ impl pallet_collective::Config<CouncilCollective> for Runtime {
 	type WeightInfo = pallet_collective::weights::SubstrateWeight<Runtime>;
 	type SetMembersOrigin = EnsureRoot<Self::AccountId>;
 	type MaxProposalWeight = MaxCollectivesProposalWeight;
+	type DisapproveOrigin = EnsureRoot<Self::AccountId>;
+	type KillOrigin = EnsureRoot<Self::AccountId>;
+	type Consideration = HoldConsideration<
+		AccountId,
+		Balances,
+		ProposalHoldReason,
+		pallet_collective::deposit::Delayed<
+			ConstU32<2>,
+			pallet_collective::deposit::Linear<ConstU32<2>, ProposalDepositOffset>,
+		>,
+		u32,
+	>;
 }
 
 parameter_types! {
@@ -1189,6 +1204,9 @@ impl pallet_collective::Config<TechnicalCollective> for Runtime {
 	type WeightInfo = pallet_collective::weights::SubstrateWeight<Runtime>;
 	type SetMembersOrigin = EnsureRoot<Self::AccountId>;
 	type MaxProposalWeight = MaxCollectivesProposalWeight;
+	type DisapproveOrigin = EnsureRoot<Self::AccountId>;
+	type KillOrigin = EnsureRoot<Self::AccountId>;
+	type Consideration = ();
 }
 
 type EnsureRootOrHalfCouncil = EitherOfDiverse<
@@ -2027,6 +2045,9 @@ impl pallet_collective::Config<AllianceCollective> for Runtime {
 	type WeightInfo = pallet_collective::weights::SubstrateWeight<Runtime>;
 	type SetMembersOrigin = EnsureRoot<Self::AccountId>;
 	type MaxProposalWeight = MaxCollectivesProposalWeight;
+	type DisapproveOrigin = EnsureRoot<Self::AccountId>;
+	type KillOrigin = EnsureRoot<Self::AccountId>;
+	type Consideration = ();
 }
 
 parameter_types! {

substrate/frame/alliance/src/mock.rs

@@ -77,6 +77,9 @@ impl pallet_collective::Config<AllianceCollective> for Test {
 	type WeightInfo = ();
 	type SetMembersOrigin = EnsureRoot<Self::AccountId>;
 	type MaxProposalWeight = MaxProposalWeight;
+	type DisapproveOrigin = EnsureRoot<Self::AccountId>;
+	type KillOrigin = EnsureRoot<Self::AccountId>;
+	type Consideration = ();
 }
 
 parameter_types! {

substrate/frame/balances/src/tests/fungible_tests.rs

@@ -518,8 +518,9 @@ fn freeze_consideration_works() {
 			let who = 4;
 			// freeze amount taken somewhere outside of our (Consideration) scope.
 			let extend_freeze = 15;
-			let zero_ticket = Consideration::new(&who, Footprint::from_parts(0, 0)).unwrap();
-			assert!(zero_ticket.is_none());
+
+			let ticket = Consideration::new(&who, Footprint::from_parts(0, 0)).unwrap();
+			assert!(ticket.is_none());
 			assert_eq!(Balances::balance_frozen(&TestId::Foo, &who), 0);
 
 			let ticket = Consideration::new(&who, Footprint::from_parts(10, 1)).unwrap();
@@ -536,7 +537,6 @@ fn freeze_consideration_works() {
 
 			let ticket = ticket.update(&who, Footprint::from_parts(0, 0)).unwrap();
 			assert!(ticket.is_none());
-			assert_eq!(ticket, zero_ticket);
 			assert_eq!(Balances::balance_frozen(&TestId::Foo, &who), 0 + extend_freeze);
 
 			let ticket = Consideration::new(&who, Footprint::from_parts(10, 1)).unwrap();
@@ -565,11 +565,11 @@ fn hold_consideration_works() {
 			// hold amount taken somewhere outside of our (Consideration) scope.
 			let extend_hold = 15;
 
-			let zero_ticket = Consideration::new(&who, Footprint::from_parts(0, 0)).unwrap();
-			assert!(zero_ticket.is_none());
+			let ticket = Consideration::new(&who, Footprint::from_parts(0, 0)).unwrap();
+			assert!(ticket.is_none());
 			assert_eq!(Balances::balance_on_hold(&TestId::Foo, &who), 0);
 
-			let ticket = Consideration::new(&who, Footprint::from_parts(10, 1)).unwrap();
+			let ticket = ticket.update(&who, Footprint::from_parts(10, 1)).unwrap();
 			assert_eq!(Balances::balance_on_hold(&TestId::Foo, &who), 10);
 
 			let ticket = ticket.update(&who, Footprint::from_parts(4, 1)).unwrap();
@@ -583,7 +583,6 @@ fn hold_consideration_works() {
 
 			let ticket = ticket.update(&who, Footprint::from_parts(0, 0)).unwrap();
 			assert!(ticket.is_none());
-			assert_eq!(ticket, zero_ticket);
 			assert_eq!(Balances::balance_on_hold(&TestId::Foo, &who), 0 + extend_hold);
 
 			let ticket = Consideration::new(&who, Footprint::from_parts(10, 1)).unwrap();

substrate/frame/collective/Cargo.toml

@@ -17,15 +17,19 @@ targets = ["x86_64-unknown-linux-gnu"]
 
 [dependencies]
 codec = { features = ["derive"], workspace = true }
+docify = { workspace = true }
 log = { workspace = true }
 scale-info = { features = ["derive"], workspace = true }
 frame-benchmarking = { optional = true, workspace = true }
-frame-support = { workspace = true }
+frame-support = { features = ["experimental"], workspace = true }
 frame-system = { workspace = true }
 sp-core = { workspace = true }
 sp-io = { workspace = true }
 sp-runtime = { workspace = true }
 
+[dev-dependencies]
+pallet-balances = { workspace = true, default-features = false }
+
 [features]
 default = ["std"]
 std = [
@@ -34,6 +38,7 @@ std = [
 	"frame-support/std",
 	"frame-system/std",
 	"log/std",
+	"pallet-balances/std",
 	"scale-info/std",
 	"sp-core/std",
 	"sp-io/std",
@@ -43,10 +48,12 @@ runtime-benchmarks = [
 	"frame-benchmarking/runtime-benchmarks",
 	"frame-support/runtime-benchmarks",
 	"frame-system/runtime-benchmarks",
+	"pallet-balances/runtime-benchmarks",
 	"sp-runtime/runtime-benchmarks",
 ]
 try-runtime = [
 	"frame-support/try-runtime",
 	"frame-system/try-runtime",
+	"pallet-balances/try-runtime",
 	"sp-runtime/try-runtime",
 ]