Check that in_atoms is backed up by actual funds (#258)

* Check that in_atoms is backed up by actual funds

* fmt

* Swap tests

* fmt

* Comment

* comment'

programs/manifest/src/program/processor/swap.rs

@@ -84,6 +84,32 @@ pub(crate) fn process_swap(
 
     trace!("swap in_atoms:{in_atoms} out_atoms:{out_atoms} is_base_in:{is_base_in} is_exact_in:{is_exact_in}");
 
+    // This check is redundant with the check that will be done within token
+    // program on deposit, but it is done here to future proof in case we later
+    // remove checked math.
+    // This actually adds a new restriction that the wallet can fully fund the
+    // swap instead of a combination of wallet and existing withdrawable
+    // balance.
+    if is_exact_in {
+        if is_base_in {
+            require!(
+                in_atoms <= trader_base_account.get_balance_atoms(),
+                ManifestError::Overflow,
+                "Insufficient base in atoms for swap has: {} requires: {}",
+                trader_base_account.get_balance_atoms(),
+                in_atoms,
+            )?;
+        } else {
+            require!(
+                in_atoms <= trader_quote_account.get_balance_atoms(),
+                ManifestError::Overflow,
+                "Insufficient quote in atoms for swap has: {} requires: {}",
+                trader_quote_account.get_balance_atoms(),
+                in_atoms,
+            )?;
+        }
+    }
+
     // this is a virtual credit to ensure matching always proceeds
     // net token transfers will be handled later
     dynamic_account.deposit(trader_index, in_atoms, is_base_in)?;

programs/manifest/tests/cases/loaders.rs

@@ -256,6 +256,14 @@ async fn swap_wrong_token_accounts() -> anyhow::Result<()> {
     test_fixture
         .deposit(Token::USDC, USDC_UNIT_SIZE * 1_000)
         .await?;
+    test_fixture
+        .sol_mint_fixture
+        .mint_to(&test_fixture.payer_sol_fixture.key, 1 * SOL_UNIT_SIZE)
+        .await;
+    test_fixture
+        .usdc_mint_fixture
+        .mint_to(&test_fixture.payer_usdc_fixture.key, 1 * USDC_UNIT_SIZE)
+        .await;
 
     test_fixture
         .place_order(

programs/manifest/tests/cases/swap.rs

@@ -27,6 +27,11 @@ use crate::{
 async fn swap_test() -> anyhow::Result<()> {
     let mut test_fixture: TestFixture = TestFixture::new().await;
 
+    test_fixture
+        .sol_mint_fixture
+        .mint_to(&test_fixture.payer_sol_fixture.key, 1 * SOL_UNIT_SIZE)
+        .await;
+
     // No deposits or seat claims needed
     test_fixture.swap(SOL_UNIT_SIZE, 0, true, true).await?;