Test/remit split schedule id sequencing

remittance_split/README.md

@@ -25,6 +25,7 @@ in strict order before any token interaction occurs:
    Returns `SelfTransferNotAllowed` if any match.
 7. **Replay protection** — nonce must equal `get_nonce(from)` and is incremented after success.
 8. **Audit + event** — a `DistributionCompleted` event is emitted on success for off-chain indexing.
+9. **Schedule ID Sequencing** — `create_remittance_schedule` generates strictly monotonic IDs using a synchronized counter (`NEXT_RSCH`), ensuring no collisions across high-volume operations.
 
 ## Features
 

remittance_split/src/lib.rs

@@ -1341,8 +1341,16 @@ impl RemittanceSplit {
             .storage()
             .instance()
             .get(&symbol_short!("NEXT_RSCH"))
-            .unwrap_or(0u32)
-            + 1;
+            .unwrap_or(0u32);
+
+        let next_schedule_id = current_max_id
+            .checked_add(1)
+            .ok_or(RemittanceSplitError::Overflow)?;
+
+        // Explicit uniqueness check to prevent any potential storage collisions
+        if schedules.contains_key(next_schedule_id) {
+            return Err(RemittanceSplitError::Overflow); // Should be unreachable with monotonic counter
+        }
 
         let schedule = RemittanceSchedule {
             id: next_schedule_id,

remittance_split/tests/stress_test_large_amounts.rs

@@ -254,3 +254,88 @@ fn test_insurance_remainder_calculation_with_large_values() {
     let total: i128 = amounts.iter().sum();
     assert_eq!(total, large_amount);
 }
+#[test]
+fn test_schedule_id_sequencing_monotonicity() {
+    let env = Env::default();
+    let contract_id = env.register_contract(None, RemittanceSplit);
+    let client = RemittanceSplitClient::new(&env, &contract_id);
+    let owner = <Address as AddressTrait>::generate(&env);
+    env.mock_all_auths();
+
+    let amount = 1000_i128;
+    let next_due = env.ledger().timestamp() + 86400;
+    let interval = 86400;
+
+    let mut last_id = 0;
+    for _ in 0..100 {
+        let id = client.create_remittance_schedule(&owner, &amount, &next_due, &interval);
+        assert!(id > last_id, "Schedule IDs must be strictly monotonic");
+        last_id = id;
+    }
+}
+
+#[test]
+fn test_schedule_id_uniqueness_across_operations() {
+    let env = Env::default();
+    let contract_id = env.register_contract(None, RemittanceSplit);
+    let client = RemittanceSplitClient::new(&env, &contract_id);
+    let owner = <Address as AddressTrait>::generate(&env);
+    env.mock_all_auths();
+
+    let amount = 1000_i128;
+    let next_due = env.ledger().timestamp() + 86400;
+    let interval = 86400;
+
+    // 1. Create several schedules
+    let id1 = client.create_remittance_schedule(&owner, &amount, &next_due, &interval);
+    let id2 = client.create_remittance_schedule(&owner, &amount, &next_due, &interval);
+    let id3 = client.create_remittance_schedule(&owner, &amount, &next_due, &interval);
+
+    assert_ne!(id1, id2);
+    assert_ne!(id2, id3);
+
+    // 2. Modify one
+    client.modify_remittance_schedule(&owner, &id1, &(amount * 2), &(next_due + 100), &interval);
+    let mod_schedule = client.get_remittance_schedule(&id1).unwrap();
+    assert_eq!(mod_schedule.id, id1, "Schedule ID must remain stable after modification");
+
+    // 3. Cancel one
+    client.cancel_remittance_schedule(&owner, &id2);
+    let cancelled = client.get_remittance_schedule(&id2).unwrap();
+    assert_eq!(cancelled.active, false);
+
+    // 4. Create new one and verify it doesn't collide with ANY previous ID (including cancelled/modified)
+    let id4 = client.create_remittance_schedule(&owner, &amount, &next_due, &interval);
+    assert!(id4 > id3, "New ID must be greater than all previous IDs");
+    assert_ne!(id4, id1);
+    assert_ne!(id4, id2);
+    assert_ne!(id4, id3);
+}
+
+#[test]
+fn test_high_volume_schedule_creation_no_collisions() {
+    let env = Env::default();
+    env.budget().reset_unlimited();
+    let contract_id = env.register_contract(None, RemittanceSplit);
+    let client = RemittanceSplitClient::new(&env, &contract_id);
+    let owner = <Address as AddressTrait>::generate(&env);
+    env.mock_all_auths();
+
+    let amount = 1000_i128;
+    let next_due = env.ledger().timestamp() + 86400;
+
+    // Create 500 schedules and track IDs
+    let mut ids = soroban_sdk::Vec::new(&env);
+    for i in 0..500 {
+        let id = client.create_remittance_schedule(&owner, &amount, &(next_due + i as u64), &0);
+        ids.push_back(id);
+    }
+
+    // Verify all IDs are unique (O(n^2) check if necessary, or sort)
+    // In soroban testing we can just use a Map for O(n)
+    let mut seen = soroban_sdk::Map::new(&env);
+    for id in ids.iter() {
+        assert!(seen.get(id).is_none(), "Collision detected for schedule ID: {}", id);
+        seen.set(id, true);
+    }
+}