backstop: cap q4w length and extend emission allowance TTL

backstop/src/backstop/deposit.rs

@@ -121,7 +121,6 @@ mod tests {
         e.as_contract(&backstop_address, || {
             execute_deposit(&e, &samwise, &pool_0_id, 100_0000001);
 
-            // TODO: Handle token errors gracefully
             assert!(false);
         });
     }

backstop/src/backstop/user.rs

@@ -1,6 +1,9 @@
 use soroban_sdk::{contracttype, panic_with_error, vec, Env, Vec};
 
-use crate::errors::BackstopError;
+use crate::{
+    constants::{MAX_Q4W_SIZE, Q4W_LOCK_TIME},
+    errors::BackstopError,
+};
 
 /// A deposit that is queued for withdrawal
 #[derive(Clone)]
@@ -51,14 +54,15 @@ impl UserBalance {
         if self.shares < to_q {
             panic_with_error!(e, BackstopError::BalanceError);
         }
+        if self.q4w.len() >= MAX_Q4W_SIZE {
+            panic_with_error!(e, BackstopError::TooManyQ4WEntries);
+        }
         self.shares = self.shares - to_q;
 
         // user has enough tokens to withdrawal, add Q4W
-        // TODO: Consider capping how many active Q4Ws a user can have
-        let twentyone_days_in_sec = 21 * 24 * 60 * 60;
         let new_q4w = Q4W {
             amount: to_q,
-            exp: e.ledger().timestamp() + twentyone_days_in_sec,
+            exp: e.ledger().timestamp() + Q4W_LOCK_TIME,
         };
         self.q4w.push_back(new_q4w.clone());
     }
@@ -210,6 +214,75 @@ mod tests {
         assert_eq_vec_q4w(&user.q4w, &cur_q4w);
     }
 
+    #[test]
+    fn test_q4w_new_to_max_works() {
+        let e = Env::default();
+        let exp = 12592000;
+        let mut cur_q4w = vec![&e];
+        for i in 0..20 {
+            cur_q4w.push_back(Q4W {
+                amount: 200,
+                exp: exp + i,
+            });
+        }
+        let mut user = UserBalance {
+            shares: 1000,
+            q4w: cur_q4w.clone(),
+        };
+
+        e.ledger().set(LedgerInfo {
+            protocol_version: 20,
+            sequence_number: 1,
+            timestamp: 11000000,
+            network_id: Default::default(),
+            base_reserve: 10,
+            min_temp_entry_ttl: 10,
+            min_persistent_entry_ttl: 10,
+            max_entry_ttl: 3110400,
+        });
+
+        let to_queue = 500;
+        user.queue_shares_for_withdrawal(&e, to_queue);
+        cur_q4w.push_back(Q4W {
+            amount: to_queue,
+            exp: 11000000 + 21 * 24 * 60 * 60,
+        });
+        assert_eq_vec_q4w(&user.q4w, &cur_q4w);
+    }
+
+    #[test]
+    #[should_panic(expected = "Error(Contract, #1007)")]
+    fn test_q4w_new_over_max_panics() {
+        let e = Env::default();
+
+        let exp = 12592000;
+        let mut cur_q4w = vec![&e];
+        for i in 0..21 {
+            cur_q4w.push_back(Q4W {
+                amount: 200,
+                exp: exp + i,
+            });
+        }
+        let mut user = UserBalance {
+            shares: 1000,
+            q4w: cur_q4w.clone(),
+        };
+
+        e.ledger().set(LedgerInfo {
+            protocol_version: 20,
+            sequence_number: 1,
+            timestamp: 11000000,
+            network_id: Default::default(),
+            base_reserve: 10,
+            min_temp_entry_ttl: 10,
+            min_persistent_entry_ttl: 10,
+            max_entry_ttl: 3110400,
+        });
+
+        let to_queue = 500;
+        user.queue_shares_for_withdrawal(&e, to_queue);
+    }
+
     #[test]
     #[should_panic(expected = "Error(Contract, #10)")]
     fn test_q4w_over_shares_panics() {

backstop/src/constants.rs

@@ -5,3 +5,10 @@ pub const SCALAR_7: i128 = 1_0000000;
 /// actual deployment time and should not be considered accruate. It is only used to determine reward
 /// zone size on ~90 day intervals, starting at 10 on or before April 15th, 2024 00:00:00 UTC.
 pub const BACKSTOP_EPOCH: u64 = 1713139200;
+
+/// The maximum amount of active Q4W entries that a user can have against a single backstop.
+/// Set such that a user can create a maximum of 1 entry per day over the 21 day lock period.
+pub const MAX_Q4W_SIZE: u32 = 21;
+
+/// The time in seconds that a Q4W entry is locked for (21 days).
+pub const Q4W_LOCK_TIME: u64 = 21 * 24 * 60 * 60;

backstop/src/emissions/manager.rs

@@ -93,8 +93,6 @@ pub fn gulp_emissions(e: &Env) -> i128 {
 
     let mut rz_balance: Vec<PoolBalance> = vec![e];
 
-    // TODO: Potential to assume optimization of backstop token balances ~= RZ tokens
-    //       However, linear iteration over the RZ will still occur
     // fetch total tokens of BLND in the reward zone
     let mut total_non_queued_tokens: i128 = 0;
     for rz_pool_index in 0..rz_len {
@@ -140,12 +138,12 @@ pub fn gulp_pool_emissions(e: &Env, pool_id: &Address) -> i128 {
     let blnd_token_client = TokenClient::new(e, &storage::get_blnd_token(e));
     let current_allowance = blnd_token_client.allowance(&e.current_contract_address(), pool_id);
     let new_tokens = current_allowance + pool_emissions;
-    let new_seq = e.ledger().sequence() + 17_280 * 30; // ~30 days: TODO: check phase 1 limits
+    let new_seq = e.ledger().sequence() + storage::LEDGER_BUMP_USER; // ~120 days
     blnd_token_client.approve(
         &e.current_contract_address(),
         pool_id,
         &new_tokens,
-        &new_seq, // ~30 days: TODO: check phase 1 limits
+        &new_seq,
     );
     storage::set_pool_emissions(e, pool_id, 0);
     pool_emissions

backstop/src/errors.rs

@@ -24,4 +24,5 @@ pub enum BackstopError {
     NotPool = 1004,
     InvalidShareMintAmount = 1005,
     InvalidTokenWithdrawAmount = 1006,
+    TooManyQ4WEntries = 1007,
 }

backstop/src/storage.rs

@@ -16,7 +16,7 @@ const LEDGER_THRESHOLD_SHARED: u32 = ONE_DAY_LEDGERS * 45; // ~ 45 days
 const LEDGER_BUMP_SHARED: u32 = LEDGER_THRESHOLD_SHARED + ONE_DAY_LEDGERS; // ~ 46 days
 
 const LEDGER_THRESHOLD_USER: u32 = ONE_DAY_LEDGERS * 100; // ~ 100 days
-const LEDGER_BUMP_USER: u32 = LEDGER_THRESHOLD_USER + 20 * ONE_DAY_LEDGERS; // ~ 120 days
+pub(crate) const LEDGER_BUMP_USER: u32 = LEDGER_THRESHOLD_USER + 20 * ONE_DAY_LEDGERS; // ~ 120 days
 
 /********** Storage Types **********/
 
@@ -314,8 +314,6 @@ pub fn set_last_distribution_time(e: &Env, timestamp: &u64) {
 }
 
 /// Get the current pool addresses that are in the reward zone
-///
-// @dev - TODO: Once data access costs are available, find the breakeven point for splitting this up
 pub fn get_reward_zone(e: &Env) -> Vec<Address> {
     get_persistent_default(
         e,