configurable max spread (#67)

Author: betterclever

contracts/pools/stable_pool/src/contract.rs

@@ -96,6 +96,9 @@ pub enum ContractError {
 
     #[error("Scaling factor manager shouldn't be specified if scaling factor is not updatable")]
     ScalingFactorManagerSpecified,
+
+    #[error("Invalid max allowed spread. Max allowed spread should be positive non-zero value less than 1")]
+    InvalidMaxAllowedSpread,
 }
 
 impl From<OverflowError> for ContractError {

contracts/pools/stable_pool/src/error.rs

@@ -1,7 +1,7 @@
 use std::collections::HashMap;
 
 use cosmwasm_schema::cw_serde;
-use cosmwasm_std::{DepsMut, StdResult, Storage, Uint128, Addr, Decimal256};
+use cosmwasm_std::{DepsMut, StdResult, Storage, Uint128, Addr, Decimal256, Decimal};
 use cw_storage_plus::{Item, Map};
 use dexter::asset::AssetInfo;
 use dexter::pool::Config;
@@ -35,7 +35,15 @@ pub struct MathConfig {
 
 #[cw_serde]
 pub struct StableSwapConfig {
+    /// Max allowed spread between the price of the asset and the price of the pool.
+    /// If the spread is greater than this value, the swap will fail.
+    /// This value is configurable by the Pool Manager.
+    /// Max allowed spread is in the range (0, 1) non-inclusive.
+    pub max_allowed_spread: Decimal,
+    /// If this is true, then the scaling factors can be updated by the scaling_factor_manager.
     pub supports_scaling_factors_update: bool,
+    /// The vector of scaling factors for each asset in the pool.
+    /// The scaling factor is used to scale the volume of the asset in the pool for the stableswap invariant calculations.
     pub scaling_factors: Vec<AssetScalingFactor>,
     // This address is allowed to update scaling factors. This address is required if support_scaling_factors_update is true.
     pub scaling_factor_manager: Option<Addr>,
@@ -78,6 +86,8 @@ pub struct Twap {
 pub struct StablePoolParams {
     /// The current stableswap pool amplification
     pub amp: u64,
+    /// Max allowed spread for the trades
+    pub max_allowed_spread: Decimal,
     /// Support scaling factors update
     pub supports_scaling_factors_update: bool,
     /// Scaling factors
@@ -108,6 +118,7 @@ pub enum StablePoolUpdateParams {
     StopChangingAmp {},
     UpdateScalingFactorManager { manager: Addr },
     UpdateScalingFactor { asset_info: AssetInfo, scaling_factor: Decimal256 },
+    UpdateMaxAllowedSpread { max_allowed_spread: Decimal },
 }
 
 // ----------------x----------------x----------------x----------------

contracts/pools/stable_pool/src/state.rs

@@ -307,6 +307,47 @@ fn test_update_config() {
 
     let params: StablePoolParams = from_binary(&res.additional_params.unwrap()).unwrap();
     assert_eq!(params.amp, 20u64);
+
+    // Change max allowed spread limits for trades
+    let msg = ExecuteMsg::UpdateConfig {
+        params: Some(
+            to_binary(&StablePoolUpdateParams::UpdateMaxAllowedSpread {
+                max_allowed_spread: Decimal::percent(90),
+            })
+            .unwrap(),
+        ),
+    };
+
+    app.execute_contract(owner.clone(), pool_addr.clone(), &msg, &[]).unwrap();
+    
+    // validate max allowed spread change
+    let res: ConfigResponse = app
+        .wrap()
+        .query_wasm_smart(pool_addr.clone(), &QueryMsg::Config {})
+        .unwrap();
+
+    let params: StablePoolParams = from_binary(&res.additional_params.unwrap()).unwrap();
+    assert_eq!(params.max_allowed_spread, Decimal::percent(90));
+
+    // try updating max spread to an invalid value
+    let msg = ExecuteMsg::UpdateConfig {
+        params: Some(
+            to_binary(&StablePoolUpdateParams::UpdateMaxAllowedSpread {
+                max_allowed_spread: Decimal::percent(100),
+            })
+            .unwrap(),
+        ),
+    };
+
+    let resp = app
+        .execute_contract(owner.clone(), pool_addr.clone(), &msg, &[])
+        .unwrap_err();
+
+    assert_eq!(
+        resp.root_cause().to_string(),
+        "Invalid max allowed spread. Max allowed spread should be positive non-zero value less than 1"
+    );
+
 }
 
 /// Tests the following -

contracts/pools/stable_pool/tests/integration.rs

@@ -136,6 +136,7 @@ pub fn instantiate_contract_generic(
                 scaling_factors,
                 supports_scaling_factors_update: false,
                 scaling_factor_manager: None,
+                max_allowed_spread: Decimal::from_ratio(50u128, 100u128)
             })
             .unwrap(),
         ),

contracts/pools/stable_pool/tests/utils/mod.rs

@@ -251,6 +251,7 @@ fn initialize_stable_5_pool(
             scaling_factors: vec![],
             supports_scaling_factors_update: false,
             scaling_factor_manager: None,
+            max_allowed_spread: Decimal::from_ratio(50u128, 100u128)
         }).unwrap()),
         fee_info: None,
     };

contracts/router/tests/integration.rs

@@ -1,6 +1,6 @@
 pub mod utils;
 
-use cosmwasm_std::{attr, coin, Addr, Coin, Uint128, to_binary};
+use cosmwasm_std::{attr, coin, Addr, Coin, Uint128, to_binary, Decimal};
 use cw20::MinterResponse;
 use cw_multi_test::Executor;
 use dexter::asset::AssetInfo;
@@ -531,6 +531,7 @@ fn test_pool_config_update() {
             supports_scaling_factors_update: false,
             scaling_factor_manager: None,
             scaling_factors: vec![],
+            max_allowed_spread: Decimal::from_ratio(50u128, 100u128),
         }).unwrap()),
         fee_info: None,
     };

contracts/vault/tests/initialization_and_config.rs

@@ -2,7 +2,7 @@ pub mod utils;
 
 use std::vec;
 
-use cosmwasm_std::{attr, coin, Addr, Coin, Uint128, to_binary};
+use cosmwasm_std::{attr, coin, Addr, Coin, Uint128, to_binary, Decimal};
 use cw20::MinterResponse;
 use cw_multi_test::Executor;
 use dexter::asset::{Asset, AssetInfo};
@@ -101,7 +101,8 @@ fn test_create_pool_instance() {
             amp: 100u64,
             scaling_factor_manager: None,
             supports_scaling_factors_update: false,
-            scaling_factors: vec![]
+            scaling_factors: vec![],
+            max_allowed_spread: Decimal::from_ratio(50u64, 100u64)
         }).unwrap()),
         fee_info: None,
     };
@@ -480,6 +481,7 @@ fn test_pool_creation_fee() {
             scaling_factor_manager: None,
             supports_scaling_factors_update: false,
             scaling_factors: vec![],
+            max_allowed_spread: Decimal::from_ratio(50u128, 100u128)
         }).unwrap()),
         fee_info: None,
     };

contracts/vault/tests/pool_creation.rs

@@ -262,7 +262,8 @@ pub fn dummy_pool_creation_msg(asset_infos: &[AssetInfo]) -> ExecuteMsg {
             amp: 100u64,
             scaling_factor_manager: None,
             scaling_factors: vec![],
-            supports_scaling_factors_update: false
+            supports_scaling_factors_update: false,
+            max_allowed_spread: Decimal::from_ratio(50u64, 100u64)
          }).unwrap()),
         fee_info: Some(FeeInfo {
             total_fee_bps: 1_000u16,
@@ -303,7 +304,8 @@ pub fn initialize_stable_5_pool_2_asset(
             amp: 10u64,
             scaling_factor_manager: None,
             scaling_factors: vec![],
-            supports_scaling_factors_update: false
+            supports_scaling_factors_update: false,
+            max_allowed_spread: Decimal::from_ratio(50u64, 100u64)
         }).unwrap()),
         fee_info: None,
     };
@@ -369,7 +371,8 @@ pub fn initialize_stable_5_pool(
             amp: 10u64,
             scaling_factor_manager: None,
             scaling_factors: vec![],
-            supports_scaling_factors_update: false
+            supports_scaling_factors_update: false,
+            max_allowed_spread: Decimal::from_ratio(50u64, 100u64)
         }).unwrap()),
         fee_info: None,
     };

contracts/vault/tests/utils/mod.rs

@@ -8,12 +8,9 @@ use std::fmt::{Display, Formatter, Result};
 use cw_storage_plus::Item;
 use crate::helper::{EventExt};
 
-/// The default slippage (0.5%)
+/// The default spread (0.5%)
 pub const DEFAULT_SPREAD: &str = "0.005";
 
-/// The maximum allowed slippage (50%)
-pub const MAX_SPREAD: &str = "0.5";
-
 // ----------------x----------------x----------------x----------------x----------------x----------------
 // ----------------x----------------x      Gneneric struct Types      x----------------x----------------
 // ----------------x----------------x----------------x----------------x----------------x----------------