From 517d472868e40689824be7edc8f4b6d6c26712d9 Mon Sep 17 00:00:00 2001
From: Collins Ikechukwu <collinschristroa@gmail.com>
Date: Sat, 17 May 2025 16:30:12 +0100
Subject: [PATCH] feat: enhance error handling in funding operations with new
 error types and improved balance checks

---
 contracts/boundless/src/datatypes.rs     |  4 +++
 contracts/boundless/src/logic/funding.rs | 31 +++++++++++++++++++-----
 2 files changed, 29 insertions(+), 6 deletions(-)

diff --git a/contracts/boundless/src/datatypes.rs b/contracts/boundless/src/datatypes.rs
index a5b8112..ed4d664 100644
--- a/contracts/boundless/src/datatypes.rs
+++ b/contracts/boundless/src/datatypes.rs
@@ -76,6 +76,10 @@ pub enum BoundlessError {
     InvalidTokenContract = 21,
     /// No backers found for the project
     NoBackerContributions = 22,
+    /// Transfer failed
+    TransferFailed = 23,
+    /// Balance check failed
+    BalanceCheckFailed = 24,
 }
 
 /// Enum representing the current status of a project
diff --git a/contracts/boundless/src/logic/funding.rs b/contracts/boundless/src/logic/funding.rs
index 5103974..09ddf52 100644
--- a/contracts/boundless/src/logic/funding.rs
+++ b/contracts/boundless/src/logic/funding.rs
@@ -54,7 +54,10 @@ impl FundingOperations for BoundlessContract {
         }
 
         let token_client = TokenClient::new(&env, &token_contract);
-        token_client.transfer(&funder, &env.current_contract_address(), &amount);
+        token_client
+            .try_transfer(&funder, &env.current_contract_address(), &amount)
+            .map_err(|_| BoundlessError::TransferFailed)?
+            .map_err(|_| BoundlessError::TransferFailed)?;
 
         let amount_u64 = amount as u64;
         project.total_funded += amount_u64;
@@ -63,7 +66,9 @@ impl FundingOperations for BoundlessContract {
         let mut found = false;
         let mut updated_backers = Vec::new(&env);
 
-        for (backer_address, backer_amount, token) in project.backers.iter() {
+        let mut i = 0;
+        while i < project.backers.len() {
+            let (backer_address, backer_amount, token) = project.backers.get_unchecked(i);
             if backer_address == funder && token == token_contract {
                 updated_backers.push_back((
                     backer_address.clone(),
@@ -74,6 +79,7 @@ impl FundingOperations for BoundlessContract {
             } else {
                 updated_backers.push_back((backer_address.clone(), backer_amount, token.clone()));
             }
+            i += 1;
         }
 
         if !found {
@@ -159,7 +165,10 @@ impl FundingOperations for BoundlessContract {
 
         let contract_address = env.current_contract_address();
         let token_client = TokenClient::new(&env, &token_contract);
-        let balance = token_client.balance(&contract_address);
+        let balance = token_client
+            .try_balance(&contract_address)
+            .map_err(|_| BoundlessError::BalanceCheckFailed)?
+            .map_err(|_| BoundlessError::BalanceCheckFailed)?;
 
         // Check if the contract has enough balance to refund
         let mut refund_amount = 0_u64;
@@ -168,10 +177,13 @@ impl FundingOperations for BoundlessContract {
             .persistent()
             .get(&DataKey::Backers(project_id.clone()))
             .unwrap_or(Vec::new(&env));
-        for backer_contribution in backer_contributions.iter() {
+        let mut i = 0;
+        while i < backer_contributions.len() {
+            let backer_contribution = backer_contributions.get_unchecked(i);
             if backer_contribution.token == token_contract {
                 refund_amount += backer_contribution.amount;
             }
+            i += 1;
         }
 
         if balance < refund_amount as i128 {
@@ -179,7 +191,9 @@ impl FundingOperations for BoundlessContract {
         }
 
         // Process refunds for each backer
-        for backer_contribution in backer_contributions.iter() {
+        let mut i = 0;
+        while i < backer_contributions.len() {
+            let backer_contribution = backer_contributions.get_unchecked(i);
             let (backer, amount, token, _) = (
                 backer_contribution.backer.clone(),
                 backer_contribution.amount as i128,
@@ -188,6 +202,7 @@ impl FundingOperations for BoundlessContract {
             );
 
             if token != token_contract {
+                i += 1;
                 continue;
             }
 
@@ -209,6 +224,7 @@ impl FundingOperations for BoundlessContract {
                     );
                 }
             }
+            i += 1;
         }
 
         refunded_tokens.push_back(token_contract);
@@ -250,10 +266,13 @@ impl FundingOperations for BoundlessContract {
             .get(&DataKey::Project(project_id.clone()))
             .ok_or(BoundlessError::NotFound)?;
 
-        for (addr, amount, _) in project.backers.iter() {
+        let mut i = 0;
+        while i < project.backers.len() {
+            let (addr, amount, _) = project.backers.get_unchecked(i);
             if addr == backer {
                 return Ok(amount);
             }
+            i += 1;
         }
 
         Ok(0)