fix(maintenance-pool): reclaim a pro-rata share, not the full deposit

contracts/escrow/src/test.rs

@@ -1,6 +1,7 @@
 #![cfg(test)]
 
 use super::*;
+use crate::contract::{EscrowContract, EscrowContractClient};
 use soroban_sdk::{
     testutils::{storage::Persistent as _, Address as _, Ledger},
     token, vec, Address, Env,
@@ -52,6 +53,21 @@ fn test_getters_return_not_initialized_before_initialize() {
     assert_eq!(client.try_get_max_sponsors(), Err(Ok(Error::NotInitialized)));
 }
 
+#[test]
+fn test_initialize_rejects_treasury_equal_to_contract() {
+    // #516 — InvalidTreasury: the treasury must not be the contract itself.
+    let env = Env::default();
+    env.mock_all_auths();
+    let contract_id = env.register(EscrowContract, ());
+    let client = EscrowContractClient::new(&env, &contract_id);
+    let admin = Address::generate(&env);
+    let oracle = Address::generate(&env);
+
+    let result = client.try_initialize(&admin, &oracle, &contract_id, &500u32, &None);
+    assert_eq!(result, Err(Ok(Error::InvalidTreasury)));
+}
+
+
 #[test]
 fn test_initialize_rejects_fee_bps_above_10000() {
     let env = Env::default();
@@ -369,8 +385,8 @@ fn test_adversarial_ordering_resistance() {
     let admin = Address::generate(&env);
     let oracle = Address::generate(&env);
     let treasury = Address::generate(&env);
-    let contract_id = env.register(crate::EscrowContract, ());
-    let client = crate::EscrowContractClient::new(&env, &contract_id);
+    let contract_id = env.register(crate::contract::EscrowContract, ());
+    let client = crate::contract::EscrowContractClient::new(&env, &contract_id);
 
     // Initialize with 0% fee to simplify fraction/dust calculations
     client.initialize(&admin, &oracle, &treasury, &0u32, &None);
@@ -435,8 +451,8 @@ fn test_large_split_distributes_dust_by_largest_remainder() {
     let admin = Address::generate(&env);
     let oracle = Address::generate(&env);
     let treasury = Address::generate(&env);
-    let contract_id = env.register(crate::EscrowContract, ());
-    let client = crate::EscrowContractClient::new(&env, &contract_id);
+    let contract_id = env.register(crate::contract::EscrowContract, ());
+    let client = crate::contract::EscrowContractClient::new(&env, &contract_id);
     // 0% fee so the whole total is distributable.
     client.initialize(&admin, &oracle, &treasury, &0u32, &None);
 
@@ -2152,6 +2168,7 @@ fn test_set_treasury_updates_treasury_address() {
 #[test]
 fn test_set_treasury_requires_admin_auth() {
     let env = Env::default();
+    env.mock_all_auths();
     let (_, admin, _treasury, client) = setup(&env);
 
     let new_treasury = Address::generate(&env);

contracts/maintenance-pool/src/lib.rs

@@ -299,19 +299,41 @@ mod contract {
             return Err(Error::InactivityWindowNotElapsed);
         }
 
-        if deposit.amount > pool.balance {
+        // #534 — refund the sponsor's pro-rata share of the REMAINING
+        // balance, not the full original deposit. The pool is fungible and
+        // withdraw pays rewards from it, so a full refund would let an early
+        // reclaimer drain later depositors' share of the spending.
+        //   reclaimable = deposit.amount * pool.balance / total_deposited
+        let reclaimable = if pool.total_deposited > 0 {
+            deposit
+                .amount
+                .checked_mul(pool.balance)
+                .ok_or(Error::ArithmeticOverflow)?
+                .checked_div(pool.total_deposited)
+                .ok_or(Error::ArithmeticOverflow)?
+        } else {
+            deposit.amount
+        };
+        if reclaimable <= 0 {
             return Err(Error::InsufficientBalance);
         }
 
         let token_client = token::Client::new(&env, &pool.token);
-        token_client.transfer(&env.current_contract_address(), &sponsor, &deposit.amount);
+        token_client.transfer(&env.current_contract_address(), &sponsor, &reclaimable);
 
         pool.balance = pool
             .balance
+            .checked_sub(reclaimable)
+            .ok_or(Error::ArithmeticOverflow)?;
+        pool.total_deposited = pool
+            .total_deposited
             .checked_sub(deposit.amount)
             .ok_or(Error::ArithmeticOverflow)?;
         env.storage().persistent().set(&pkey, &pool);
         extend_ttl(&env, &pkey);
+        // Clear the deposit record — otherwise the same deposit could be
+        // reclaimed twice.
+        env.storage().persistent().remove(&dkey);
         extend_instance_ttl(&env);
 
         Ok(())