From 074d521c7cabd29c3e74584c0dd18f9e554a9757 Mon Sep 17 00:00:00 2001
From: laurentketterle-hub <laurentketterle-hub@users.noreply.github.com>
Date: Thu, 13 Aug 2026 04:57:46 +0200
Subject: [PATCH] fix: authorize flash loan repayment (#315) and restore
 compilation

---
 investment_vault/src/events.rs |  4 ++++
 investment_vault/src/lib.rs    | 24 ++++++++++++++++--------
 investment_vault/src/test.rs   |  2 ++
 investment_vault/src/types.rs  |  4 ++--
 4 files changed, 24 insertions(+), 10 deletions(-)

diff --git a/investment_vault/src/events.rs b/investment_vault/src/events.rs
index 03570e06..f4cb30b1 100644
--- a/investment_vault/src/events.rs
+++ b/investment_vault/src/events.rs
@@ -504,6 +504,8 @@ pub struct WithdrawalWindowSet {
 
 pub fn withdrawal_window_set(env: &Env, ledgers: u32) {
     WithdrawalWindowSet { ledgers }.publish(env);
+}
+
 /// Emitted when the admin opens a funding round (#38).
 #[contractevent]
 pub struct FundingRoundStarted {}
@@ -518,6 +520,8 @@ pub struct FundingRoundEnded {}
 
 pub fn funding_round_ended(env: &Env) {
     FundingRoundEnded {}.publish(env);
+}
+
 /// Emitted when the admin changes the per-project investment cap (#32).
 #[contractevent]
 pub struct InvestmentCapSet {
diff --git a/investment_vault/src/lib.rs b/investment_vault/src/lib.rs
index 1f384090..ce2ea7ed 100644
--- a/investment_vault/src/lib.rs
+++ b/investment_vault/src/lib.rs
@@ -1127,6 +1127,8 @@ impl InvestmentVault {
             .instance()
             .get(&VaultKey::WithdrawalWindowLedgers)
             .unwrap_or(1)
+    }
+
     // ── Dynamic fee structure (#39) ───────────────────────────────────────────
 
     /// Configure a two-tier volume-discount fee schedule for deposits (#39).
@@ -1179,6 +1181,8 @@ impl InvestmentVault {
             .get(&VaultKey::VolumeTierFeeBps)
             .unwrap_or(0);
         (threshold, bps)
+    }
+
     // ── Per-project investment cap (#32) ──────────────────────────────────────
 
     /// Set the maximum total USDC the vault may invest in any single project. Admin-only.
@@ -1475,8 +1479,18 @@ impl InvestmentVault {
             panic!("flash loan callback failed");
         }
 
-        Base::transfer(&env, &borrower, &MuxedAddress::from(&vault), amount + fee);
-        Base::burn(&env, &vault, amount);
+        // Repayment (#315): pull `amount + fee` shares back from the borrower.
+        // `Base::transfer` would call `borrower.require_auth()`, which a
+        // *contract* borrower cannot satisfy once its `flash_loan_callback` has
+        // already returned — the repayment therefore failed on a real network
+        // and only passed under `mock_all_auths()`. The borrower's consent is
+        // established by returning `true` from the callback in this same
+        // transaction, so the vault (as the token contract) moves the shares
+        // directly via the unauthenticated `Base::update` primitive.
+        Base::update(&env, Some(&borrower), Some(&vault), amount + fee);
+        // Burn the principal from the vault's own balance, leaving the fee as
+        // the vault's flash-loan revenue.
+        Base::update(&env, Some(&vault), None, amount);
 
         events::flash_loan(&env, &initiator, &borrower, amount, fee);
     }
@@ -2092,12 +2106,6 @@ fn check_deposit_lock(env: &Env, address: &Address) {
         .persistent()
         .get::<_, u64>(&VaultKey::LastDeposit(address.clone()))
     {
-        let window: u32 = env
-            .storage()
-            .instance()
-            .get(&VaultKey::WithdrawalWindowLedgers)
-            .unwrap_or(1);
-        if env.ledger().sequence() < last_seq.saturating_add(window) {
         if env.ledger().timestamp() < deposited_at + MIN_LOCK_PERIOD {
             panic_with_error!(env, VaultError::DepositLocked);
         }
diff --git a/investment_vault/src/test.rs b/investment_vault/src/test.rs
index 4be8ed36..a71cb09e 100644
--- a/investment_vault/src/test.rs
+++ b/investment_vault/src/test.rs
@@ -2586,6 +2586,8 @@ fn test_volume_fee_tier_is_admin_only() {
         },
     }]);
     s.vault_client.set_volume_fee_tier(&500_0000000i128, &50u32);
+}
+
 // ── #179: convert_to_shares() overflow guard on extremely large deposits ──────
 
 /// Verify that `convert_to_shares` panics (rather than silently wrapping) when
diff --git a/investment_vault/src/types.rs b/investment_vault/src/types.rs
index e09392d3..4fa17585 100644
--- a/investment_vault/src/types.rs
+++ b/investment_vault/src/types.rs
@@ -90,9 +90,9 @@ pub enum VaultError {
     /// batch_deposit received an empty investor list (#178).
     EmptyBatchDeposit = 41,
     /// Share transfers are blocked because a funding round is active (#38).
-    FundingRoundActive = 41,
+    FundingRoundActive = 42,
     /// Funding would push cumulative investment in a project above its per-project cap (#32).
-    InvestmentCapExceeded = 41,
+    InvestmentCapExceeded = 43,
 }
 
 #[contracttype]