Implement market creator incentives (#1057)

* Integrate creator_fee in config and market & pool creation

* Make creator_fee decideable by market creator

Also replaces CreatorFee config element by MaxCreatorFee config element. I am against this change but I got outvoted by stakeholders, reasoning can be found at https://hackmd.io/@lZVVinJVS6WI4IpRgmbsLA/H17iRm6Kn

* Finalize adjustable creator fee changes

* Plan helper function

* Partially implement market creator fees

* Implement market fees for swap_exact_amount_in

* Add tests for swap_exact_amount_in fees (WIP)

* Finalize creator fee for swap_exact_amount_in

* Fix bugs

* Finalize fee handling logic

* Use BASET_ASSET constant in tests

* Use const for pool and market id

* Add swap_in tests

* Complete swap_in with creator fee tests

* Use const for default weights

* Use imported Error instead of absolute path

* Implement limit tests when using creator fee

* Implement max price tests when using creator fee

* Complete swap_out with creator fee tests

* Fix no-base<->no-base swap out creato fee test

* Implement limit tests with swap_out when using creator fee

* Implement max price tests for swap_out when using creator fee

* Implement test to verify swap out amount is correct

* Add test that verifies fee boundaries during pool creation

* Add creator_fee migration

* Adjust all tests to new create_market call

* Format

* Update changelog

* Update changelog

* Fix invalid test

* Add fee limit test in prediction markets crate

* Fix swaps benchmarks (invalid market id)

* Update license headers

* Satisfy clippy

* Repair fuzz tests

* Fix swaps fuzz tests (invalid market id)

* Add market parameter test for create_cpmm_market_and_deploy_assets

* Adjust swap benchmarks to use worst-case execution

* Make handle_creator_fees infallible

* Add ED tests for creator fees

* Update copyright

docs/changelog_for_devs.md

@@ -34,6 +34,27 @@ All things about Global Disputes Fix ⚠️ :
 
 ### Added
 
+- Add market creator incentives.
+  - The following dispatchable calls within the prediction markets pallet now
+    expect a market creator fee denoted as type `Perbill` after the `base_asset`
+    parameter. The fee is bounded by the pallet's `Config` parameter
+    `MaxCreatorFee`:
+    - `create_market`
+    - `create_cpmm_market_and_deploy_assets`
+  - The market type now holds an additional field `creator_fee` using the type
+    `Perbill` after the `creation` field.
+  - The swaps pallet's `Config` parameter `MaxSwapFee` now is a boundary for the
+    sum of all fees, currently the liqudity provider fee and the market creator
+    fee. It is checked during the execution of the public function
+    `create_pool`.
+  - Fees are always transferred from the trader's account to the market
+    creator's account either before or after the trade. The base asset is always
+    preferred to pay fees. If the trade does not include the base asset, the
+    pallet will try to convert the outcome asset to the base asset by executing
+    a swap.
+  - A new event `MarketCreatorFeesPaid` is emitted by the swaps pallet after
+    successful payment of fees to the market creator. It contains the fields
+    `\[payer, payee, amount, asset\]`.
 - ⚠️ Add court production implementation ([#976]). Dispatchable calls are:
   - `join_court` - Join the court with a stake to become a juror in order to get
     the stake-weighted chance to be selected for decision making.

primitives/Cargo.toml

@@ -8,6 +8,7 @@ orml-traits = { workspace = true }
 parity-scale-codec = { workspace = true, features = ["derive", "max-encoded-len"] }
 scale-info = { workspace = true, features = ["derive"] }
 serde = { workspace = true, features = ["derive"], optional = true }
+sp-arithmetic = { workspace = true }
 sp-core = { workspace = true }
 sp-runtime = { workspace = true }
 

primitives/src/constants/mock.rs

@@ -25,6 +25,7 @@ use crate::{
 };
 use frame_support::{parameter_types, traits::LockIdentifier, PalletId};
 use orml_traits::parameter_type_with_key;
+use sp_arithmetic::Perbill;
 
 // Authorized
 parameter_types! {
@@ -75,6 +76,7 @@ parameter_types! {
     pub const DisputeBond: Balance = 5 * BASE;
     pub const DisputeFactor: Balance = 2 * BASE;
     pub const MaxCategories: u16 = 10;
+    pub const MaxCreatorFee: Perbill = Perbill::from_percent(1);
     pub const MaxDisputeDuration: BlockNumber = 50;
     pub const MaxDisputes: u16 = 6;
     pub const MaxEditReasonLen: u32 = 1024;

primitives/src/market.rs

@@ -21,12 +21,13 @@ use alloc::vec::Vec;
 use core::ops::{Range, RangeInclusive};
 use parity_scale_codec::{Decode, Encode, MaxEncodedLen};
 use scale_info::TypeInfo;
+use sp_arithmetic::per_things::Perbill;
 use sp_runtime::RuntimeDebug;
 
 /// Types
 ///
 /// * `AI`: Account id
-/// * `BA`: Balance type for bonds
+/// * `BA`: Balance type
 /// * `BN`: Block number
 /// * `M`: Moment (time moment)
 /// * `A`: Asset
@@ -38,8 +39,8 @@ pub struct Market<AI, BA, BN, M, A> {
     pub creator: AI,
     /// Creation type.
     pub creation: MarketCreation,
-    /// The fee the creator gets from each winning share.
-    pub creator_fee: u8,
+    /// A fee that is charged each trade and given to the market creator.
+    pub creator_fee: Perbill,
     /// Oracle that reports the outcome of this market.
     pub oracle: AI,
     /// Metadata for the market, usually a content address of IPFS
@@ -150,7 +151,7 @@ where
         AI::max_encoded_len()
             .saturating_add(A::max_encoded_len())
             .saturating_add(MarketCreation::max_encoded_len())
-            .saturating_add(u8::max_encoded_len())
+            .saturating_add(Perbill::max_encoded_len())
             .saturating_add(AI::max_encoded_len())
             // We assume that at max. a 512 bit hash function is used
             .saturating_add(u8::max_encoded_len().saturating_mul(68))
@@ -378,7 +379,7 @@ mod tests {
             base_asset: Asset::Ztg,
             creator: 1,
             creation: MarketCreation::Permissionless,
-            creator_fee: 2,
+            creator_fee: Default::default(),
             oracle: 3,
             metadata: vec![4u8; 5],
             market_type, // : MarketType::Categorical(6),

primitives/src/traits/swaps.rs

@@ -1,3 +1,4 @@
+// Copyright 2023 Forecasting Technologies LTD.
 // Copyright 2021-2022 Zeitgeist PM LLC.
 //
 // This file is part of Zeitgeist.
@@ -152,6 +153,8 @@ pub trait Swaps<AccountId> {
     /// * `asset_out`: Asset leaving the pool.
     /// * `min_asset_amount_out`: Minimum asset amount that can leave the pool.
     /// * `max_price`: Market price must be equal or less than the provided value.
+    /// * `handle_fees`: Whether additional fees are handled or not (sets LP fee to 0)
+    #[allow(clippy::too_many_arguments)]
     fn swap_exact_amount_in(
         who: AccountId,
         pool_id: PoolId,
@@ -160,6 +163,7 @@ pub trait Swaps<AccountId> {
         asset_out: Asset<Self::MarketId>,
         min_asset_amount_out: Option<Self::Balance>,
         max_price: Option<Self::Balance>,
+        handle_fees: bool,
     ) -> Result<Weight, DispatchError>;
 
     /// Swap - Exact amount out
@@ -175,6 +179,8 @@ pub trait Swaps<AccountId> {
     /// * `asset_out`: Asset leaving the pool.
     /// * `asset_amount_out`: Amount that will be transferred from the pool to the provider.
     /// * `max_price`: Market price must be equal or less than the provided value.
+    /// * `handle_fees`: Whether additional fees are handled or not (sets LP fee to 0)
+    #[allow(clippy::too_many_arguments)]
     fn swap_exact_amount_out(
         who: AccountId,
         pool_id: PoolId,
@@ -183,5 +189,6 @@ pub trait Swaps<AccountId> {
         asset_out: Asset<Self::MarketId>,
         asset_amount_out: Self::Balance,
         max_price: Option<Self::Balance>,
+        handle_fees: bool,
     ) -> Result<Weight, DispatchError>;
 }

runtime/battery-station/src/parameters.rs

@@ -205,6 +205,8 @@ parameter_types! {
     pub const DisputeBond: Balance = 25 * BASE;
     /// Maximum Categories a prediciton market can have (excluding base asset).
     pub const MaxCategories: u16 = MAX_CATEGORIES;
+    /// Max creator fee, bounds the fraction per trade volume that is moved to the market creator.
+    pub const MaxCreatorFee: Perbill = Perbill::from_percent(1);
     /// Maximum block period for a dispute.
     pub const MaxDisputeDuration: BlockNumber = MAX_DISPUTE_DURATION;
     /// Maximum number of disputes.

runtime/common/src/lib.rs

@@ -60,17 +60,17 @@ macro_rules! decl_common_types {
             orml_asset_registry::Migration<Runtime>,
             orml_unknown_tokens::Migration<Runtime>,
             pallet_xcm::migration::v1::MigrateToV1<Runtime>,
-            // IMPORTANT that AddDisputeBond comes before MoveDataToSimpleDisputes!!!
-            zrml_prediction_markets::migrations::AddDisputeBond<Runtime>,
+            // IMPORTANT that AddDisputeBondAndConvertCreatorFee comes before MoveDataToSimpleDisputes!!!
+            zrml_prediction_markets::migrations::AddDisputeBondAndConvertCreatorFee<Runtime>,
             zrml_prediction_markets::migrations::MoveDataToSimpleDisputes<Runtime>,
             zrml_global_disputes::migrations::ModifyGlobalDisputesStructures<Runtime>,
         );
 
         #[cfg(not(feature = "parachain"))]
         type Migrations = (
             pallet_grandpa::migrations::CleanupSetIdSessionMap<Runtime>,
-            // IMPORTANT that AddDisputeBond comes before MoveDataToSimpleDisputes!!!
-            zrml_prediction_markets::migrations::AddDisputeBond<Runtime>,
+            // IMPORTANT that AddDisputeBondAndConvertCreatorFee comes before MoveDataToSimpleDisputes!!!
+            zrml_prediction_markets::migrations::AddDisputeBondAndConvertCreatorFee<Runtime>,
             zrml_prediction_markets::migrations::MoveDataToSimpleDisputes<Runtime>,
             zrml_global_disputes::migrations::ModifyGlobalDisputesStructures<Runtime>,
         );
@@ -1126,6 +1126,7 @@ macro_rules! impl_config_traits {
             type LiquidityMining = NoopLiquidityMining;
             // type LiquidityMining = LiquidityMining;
             type MaxCategories = MaxCategories;
+            type MaxCreatorFee = MaxCreatorFee;
             type MaxDisputes = MaxDisputes;
             type MaxMarketLifetime = MaxMarketLifetime;
             type MinDisputeDuration = MinDisputeDuration;

runtime/zeitgeist/src/parameters.rs

@@ -205,6 +205,8 @@ parameter_types! {
     pub const DisputeBond: Balance = 2_000 * BASE;
     /// Maximum Categories a prediciton market can have (excluding base asset).
     pub const MaxCategories: u16 = MAX_CATEGORIES;
+    /// Max creator fee, bounds the fraction per trade volume that is moved to the market creator.
+    pub const MaxCreatorFee: Perbill = Perbill::from_percent(1);
     /// Maximum block period for a dispute.
     pub const MaxDisputeDuration: BlockNumber = MAX_DISPUTE_DURATION;
     /// Maximum number of disputes.

zrml/authorized/src/lib.rs

@@ -382,7 +382,7 @@ where
     zeitgeist_primitives::types::Market {
         base_asset: Asset::Ztg,
         creation: zeitgeist_primitives::types::MarketCreation::Permissionless,
-        creator_fee: 0,
+        creator_fee: sp_runtime::Perbill::zero(),
         creator: T::PalletId::get().into_account_truncating(),
         market_type: zeitgeist_primitives::types::MarketType::Scalar(0..=100),
         dispute_mechanism: zeitgeist_primitives::types::MarketDisputeMechanism::Authorized,

zrml/court/src/benchmarks.rs

@@ -56,7 +56,7 @@ where
     Market {
         base_asset: Asset::Ztg,
         creation: MarketCreation::Permissionless,
-        creator_fee: 0,
+        creator_fee: sp_runtime::Perbill::zero(),
         creator: account("creator", 0, 0),
         market_type: MarketType::Scalar(0..=100),
         dispute_mechanism: MarketDisputeMechanism::Court,

zrml/court/src/tests.rs

@@ -64,7 +64,7 @@ const ORACLE_REPORT: OutcomeReport = OutcomeReport::Scalar(u128::MAX);
 const DEFAULT_MARKET: MarketOf<Runtime> = Market {
     base_asset: Asset::Ztg,
     creation: MarketCreation::Permissionless,
-    creator_fee: 0,
+    creator_fee: sp_runtime::Perbill::zero(),
     creator: 0,
     market_type: MarketType::Scalar(0..=100),
     dispute_mechanism: MarketDisputeMechanism::Court,

zrml/global-disputes/src/utils.rs

@@ -42,7 +42,7 @@ where
     zeitgeist_primitives::types::Market {
         base_asset: zeitgeist_primitives::types::Asset::Ztg,
         creation: zeitgeist_primitives::types::MarketCreation::Permissionless,
-        creator_fee: 0,
+        creator_fee: sp_runtime::Perbill::zero(),
         creator: T::GlobalDisputesPalletId::get().into_account_truncating(),
         market_type: zeitgeist_primitives::types::MarketType::Scalar(0..=u128::MAX),
         dispute_mechanism: zeitgeist_primitives::types::MarketDisputeMechanism::SimpleDisputes,

zrml/liquidity-mining/src/tests.rs

@@ -205,7 +205,7 @@ fn create_default_market(market_id: u128, period: Range<u64>) {
         Market {
             base_asset: Asset::Ztg,
             creation: MarketCreation::Permissionless,
-            creator_fee: 0,
+            creator_fee: sp_runtime::Perbill::zero(),
             creator: 0,
             market_type: MarketType::Categorical(0),
             dispute_mechanism: MarketDisputeMechanism::SimpleDisputes,

zrml/market-commons/src/tests.rs

@@ -23,7 +23,7 @@ use crate::{
     MarketCounter, Markets,
 };
 use frame_support::{assert_err, assert_noop, assert_ok};
-use sp_runtime::DispatchError;
+use sp_runtime::{DispatchError, Perbill};
 use zeitgeist_primitives::{
     traits::MarketCommonsPalletApi,
     types::{
@@ -36,7 +36,7 @@ use zeitgeist_primitives::{
 const MARKET_DUMMY: Market<AccountIdTest, Balance, BlockNumber, Moment, Asset<MarketId>> = Market {
     base_asset: Asset::Ztg,
     creation: MarketCreation::Permissionless,
-    creator_fee: 0,
+    creator_fee: Perbill::zero(),
     creator: 0,
     market_type: MarketType::Scalar(0..=100),
     dispute_mechanism: MarketDisputeMechanism::Authorized,

zrml/prediction-markets/fuzz/Cargo.toml

@@ -8,6 +8,7 @@ test = false
 arbitrary = { workspace = true, features = ["derive"] }
 frame-support = { workspace = true, features = ["default"] }
 libfuzzer-sys = { workspace = true }
+sp-arithmetic = { workspace = true, features = ["default"] }
 zeitgeist-primitives = { workspace = true, features = ["arbitrary", "mock", "default"] }
 zrml-prediction-markets = { workspace = true, features = ["mock", "default"] }
 zrml-simple-disputes = { workspace = true, features = ["default"] }

zrml/prediction-markets/fuzz/pm_full_workflow.rs

@@ -22,9 +22,13 @@ use arbitrary::Arbitrary;
 use core::ops::{Range, RangeInclusive};
 use frame_support::traits::Hooks;
 use libfuzzer_sys::fuzz_target;
-use zeitgeist_primitives::types::{
-    Asset, Deadlines, MarketCreation, MarketDisputeMechanism, MarketPeriod, MarketType, MultiHash,
-    OutcomeReport, ScoringRule,
+use sp_arithmetic::Perbill;
+use zeitgeist_primitives::{
+    constants::mock::MaxCreatorFee,
+    types::{
+        Asset, Deadlines, MarketCreation, MarketDisputeMechanism, MarketPeriod, MarketType,
+        MultiHash, OutcomeReport, ScoringRule,
+    },
 };
 use zrml_prediction_markets::mock::{ExtBuilder, PredictionMarkets, RuntimeOrigin, System};
 
@@ -39,9 +43,13 @@ fuzz_target!(|data: Data| {
             oracle_duration: 1_u32.into(),
             dispute_duration: 3_u32.into(),
         };
+        let max_parts_per_bill = MaxCreatorFee::get().deconstruct();
+        let bounded_parts = data.create_scalar_market_fee % max_parts_per_bill as u128;
+        let fee = Perbill::from_parts(bounded_parts.try_into().unwrap());
         let _ = PredictionMarkets::create_market(
             RuntimeOrigin::signed(data.create_scalar_market_origin.into()),
             Asset::Ztg,
+            fee,
             data.create_scalar_market_oracle.into(),
             MarketPeriod::Block(data.create_scalar_market_period),
             deadlines,
@@ -95,6 +103,7 @@ fuzz_target!(|data: Data| {
 struct Data {
     create_scalar_market_origin: u8,
     create_scalar_market_oracle: u8,
+    create_scalar_market_fee: u128,
     create_scalar_market_period: Range<u64>,
     create_scalar_market_metadata: MultiHash,
     create_scalar_market_creation: u8,

zrml/prediction-markets/src/benchmarks.rs

@@ -34,7 +34,10 @@ use frame_support::{
 };
 use frame_system::RawOrigin;
 use orml_traits::MultiCurrency;
-use sp_runtime::traits::{One, SaturatedConversion, Saturating, Zero};
+use sp_runtime::{
+    traits::{One, SaturatedConversion, Saturating, Zero},
+    Perbill,
+};
 use zeitgeist_primitives::{
     constants::mock::{MaxSwapFee, MinWeight, BASE, MILLISECS_PER_BLOCK},
     traits::{DisputeApi, Swaps},
@@ -89,11 +92,13 @@ fn create_market_common<T: Config + pallet_timestamp::Config>(
     pallet_timestamp::Pallet::<T>::set_timestamp(0u32.into());
     let range_start: MomentOf<T> = 100_000u64.saturated_into();
     let range_end: MomentOf<T> = 1_000_000u64.saturated_into();
+    let creator_fee: Perbill = Perbill::zero();
     let period = period.unwrap_or(MarketPeriod::Timestamp(range_start..range_end));
     let (caller, oracle, deadlines, metadata, creation) =
         create_market_common_parameters::<T>(permission)?;
     Call::<T>::create_market {
         base_asset: Asset::Ztg,
+        creator_fee,
         oracle,
         period,
         deadlines,
@@ -625,6 +630,7 @@ benchmarks! {
     }: _(
             RawOrigin::Signed(caller),
             Asset::Ztg,
+            Perbill::zero(),
             oracle,
             period,
             deadlines,
@@ -648,6 +654,7 @@ benchmarks! {
             create_market_common_parameters::<T>(MarketCreation::Advised)?;
         Call::<T>::create_market {
             base_asset: Asset::Ztg,
+            creator_fee: Perbill::zero(),
             oracle: oracle.clone(),
             period: period.clone(),
             deadlines,