Issue 159 add position caps

pool/src/contract.rs

@@ -48,6 +48,15 @@ pub trait Pool {
     /// If the caller is not the admin
     fn set_admin(e: Env, new_admin: Address);
 
+    /// (Admin only) Set a max number of positions a single user can have
+    ///
+    /// ### Arguments
+    /// * `max` - Max number of positions a single user can have
+    ///
+    /// ### Panics
+    /// If the caller is not the admin
+    fn set_max_positions(e: Env, max: u32);
+
     /// (Admin only) Update the pool
     ///
     /// ### Arguments
@@ -271,6 +280,17 @@ impl Pool for PoolContract {
             .publish((Symbol::new(&e, "update_pool"), admin), backstop_take_rate);
     }
 
+    fn set_max_positions(e: Env, max: u32) {
+        storage::extend_instance(&e);
+        let admin = storage::get_admin(&e);
+        admin.require_auth();
+
+        storage::set_max_positions(&e, &max);
+
+        e.events()
+            .publish((Symbol::new(&e, "set_max_positions"), admin), max);
+    }
+
     fn queue_set_reserve(e: Env, asset: Address, metadata: ReserveConfig) {
         storage::extend_instance(&e);
         let admin = storage::get_admin(&e);

pool/src/errors.rs

@@ -18,6 +18,7 @@ pub enum PoolError {
     InvalidHf = 10,
     InvalidPoolStatus = 11,
     InvalidUtilRate = 12,
+    MaxPositionsExceeded = 13,
     // Emission Errors (20-29)
     EmissionFailure = 20,
     // Oracle Errors (30-39)

pool/src/pool/submit.rs

@@ -41,6 +41,9 @@ pub fn execute_submit(
         TokenClient::new(e, &address).transfer(spender, &e.current_contract_address(), &amount);
     }
 
+    // ensure user is under max positions
+    new_from_state.positions.require_under_max(e);
+
     // store updated info to ledger
     pool.store_cached_reserves(e);
     new_from_state.store(e);
@@ -121,6 +124,7 @@ mod tests {
         };
         e.as_contract(&pool, || {
             e.mock_all_auths_allowing_non_root_auth();
+            storage::set_max_positions(&e, &2);
             storage::set_pool_config(&e, &pool_config);
 
             let pre_pool_balance_0 = underlying_0_client.balance(&pool);
@@ -160,7 +164,79 @@ mod tests {
             assert_eq!(underlying_1_client.balance(&merry), 1_5000000);
         });
     }
+    #[test]
+    #[should_panic(expected = "Error(Contract, #13)")]
+    fn test_submit_requires_positions_under_max() {
+        let e = Env::default();
+        e.budget().reset_unlimited();
+        e.mock_all_auths_allowing_non_root_auth();
+
+        e.ledger().set(LedgerInfo {
+            timestamp: 600,
+            protocol_version: 20,
+            sequence_number: 1234,
+            network_id: Default::default(),
+            base_reserve: 10,
+            min_temp_entry_ttl: 10,
+            min_persistent_entry_ttl: 10,
+            max_entry_ttl: 2000000,
+        });
+
+        let bombadil = Address::generate(&e);
+        let samwise = Address::generate(&e);
+        let frodo = Address::generate(&e);
+        let merry = Address::generate(&e);
+        let pool = testutils::create_pool(&e);
+        let (oracle, oracle_client) = testutils::create_mock_oracle(&e);
+
+        let (underlying_0, underlying_0_client) = testutils::create_token_contract(&e, &bombadil);
+        let (reserve_config, reserve_data) = testutils::default_reserve_meta();
+        testutils::create_reserve(&e, &pool, &underlying_0, &reserve_config, &reserve_data);
 
+        let (underlying_1, underlying_1_client) = testutils::create_token_contract(&e, &bombadil);
+        let (reserve_config, reserve_data) = testutils::default_reserve_meta();
+        testutils::create_reserve(&e, &pool, &underlying_1, &reserve_config, &reserve_data);
+
+        underlying_0_client.mint(&frodo, &16_0000000);
+
+        oracle_client.set_data(
+            &bombadil,
+            &Asset::Other(Symbol::new(&e, "USD")),
+            &vec![
+                &e,
+                Asset::Stellar(underlying_0.clone()),
+                Asset::Stellar(underlying_1.clone()),
+            ],
+            &7,
+            &300,
+        );
+        oracle_client.set_price_stable(&vec![&e, 1_0000000, 5_0000000]);
+
+        let pool_config = PoolConfig {
+            oracle,
+            bstop_rate: 0_100_000_000,
+            status: 0,
+        };
+        e.as_contract(&pool, || {
+            e.mock_all_auths_allowing_non_root_auth();
+            storage::set_pool_config(&e, &pool_config);
+
+            let requests = vec![
+                &e,
+                Request {
+                    request_type: 2,
+                    address: underlying_0,
+                    amount: 15_0000000,
+                },
+                Request {
+                    request_type: 4,
+                    address: underlying_1,
+                    amount: 1_5000000,
+                },
+            ];
+            execute_submit(&e, &samwise, &frodo, &merry, requests);
+        });
+    }
     #[test]
     #[should_panic(expected = "Error(Contract, #10)")]
     fn test_submit_requires_healhty() {

pool/src/pool/user.rs

@@ -1,6 +1,6 @@
-use soroban_sdk::{contracttype, Address, Env, Map};
+use soroban_sdk::{contracttype, panic_with_error, Address, Env, Map};
 
-use crate::{emissions, storage, validator::require_nonnegative};
+use crate::{emissions, storage, validator::require_nonnegative, PoolError};
 
 use super::{Pool, Reserve};
 
@@ -22,6 +22,11 @@ impl Positions {
             supply: Map::new(e),
         }
     }
+    pub fn require_under_max(&self, e: &Env) {
+        if storage::get_max_positions(e) < self.liabilities.len() + self.collateral.len() as u32 {
+            panic_with_error!(e, PoolError::MaxPositionsExceeded)
+        }
+    }
 }
 
 /// A user / contracts position's with the pool
@@ -855,4 +860,61 @@ mod tests {
             assert_eq!(user.get_total_supply(1), 456 + 789);
         });
     }
+
+    #[test]
+    fn test_require_under_max_passes() {
+        let e = Env::default();
+        let samwise = Address::generate(&e);
+        let pool = testutils::create_pool(&e);
+
+        let mut reserve_0 = testutils::default_reserve(&e);
+
+        let mut user = User {
+            address: samwise.clone(),
+            positions: Positions::env_default(&e),
+        };
+        e.as_contract(&pool, || {
+            storage::set_max_positions(&e, &1);
+            user.add_collateral(&e, &mut reserve_0, 123);
+            user.positions.require_under_max(&e);
+        });
+    }
+    #[test]
+    #[should_panic(expected = "Error(Contract, #13)")]
+    fn test_require_under_max_fails() {
+        let e = Env::default();
+        let samwise = Address::generate(&e);
+        let pool = testutils::create_pool(&e);
+
+        let mut reserve_0 = testutils::default_reserve(&e);
+
+        let mut user = User {
+            address: samwise.clone(),
+            positions: Positions::env_default(&e),
+        };
+        e.as_contract(&pool, || {
+            storage::set_max_positions(&e, &1);
+            user.add_collateral(&e, &mut reserve_0, 123);
+            user.add_liabilities(&e, &mut reserve_0, 789);
+            user.positions.require_under_max(&e);
+        });
+    }
+    #[test]
+    #[should_panic(expected = "Error(Contract, #13)")]
+    fn test_require_under_max_fails_unset() {
+        let e = Env::default();
+        let samwise = Address::generate(&e);
+        let pool = testutils::create_pool(&e);
+
+        let mut reserve_0 = testutils::default_reserve(&e);
+
+        let mut user = User {
+            address: samwise.clone(),
+            positions: Positions::env_default(&e),
+        };
+        e.as_contract(&pool, || {
+            user.add_collateral(&e, &mut reserve_0, 123);
+            user.positions.require_under_max(&e);
+        });
+    }
 }

pool/src/storage.rs

@@ -94,6 +94,7 @@ pub struct UserEmissionData {
 /********** Storage Key Types **********/
 
 const ADMIN_KEY: &str = "Admin";
+const MAX_POSITIONS_KEY: &str = "MaxPos";
 const NAME_KEY: &str = "Name";
 const BACKSTOP_KEY: &str = "Backstop";
 const BLND_TOKEN_KEY: &str = "BLNDTkn";
@@ -227,6 +228,26 @@ pub fn has_admin(e: &Env) -> bool {
     e.storage().instance().has(&Symbol::new(e, ADMIN_KEY))
 }
 
+/*********** Max Positions ***********/
+// Fetch the current max posoitions
+///
+pub fn get_max_positions(e: &Env) -> u32 {
+    e.storage()
+        .instance()
+        .get(&Symbol::new(e, MAX_POSITIONS_KEY))
+        .unwrap_or(0)
+}
+
+/// Set a new admin
+///
+/// ### Arguments
+/// * `max_positions` - The max positions for the pool
+pub fn set_max_positions(e: &Env, max_positions: &u32) {
+    e.storage()
+        .instance()
+        .set::<Symbol, u32>(&Symbol::new(e, MAX_POSITIONS_KEY), max_positions);
+}
+
 /********** Metadata **********/
 
 /// Set a pool name

test-suites/src/setup.rs

@@ -73,6 +73,9 @@ pub fn create_fixture_with_data<'a>(wasm: bool) -> TestFixture<'a> {
     ];
     pool_fixture.pool.set_emissions_config(&reserve_emissions);
 
+    // set max positions for pool
+    pool_fixture.pool.set_max_positions(&6);
+
     // deposit into backstop, add to reward zone
     fixture
         .backstop