From 35bfa935164ce127c24f2811275b18098eb51d90 Mon Sep 17 00:00:00 2001
From: 0xfnzero <0xfnzero@users.noreply.github.com>
Date: Mon, 6 Apr 2026 16:53:36 +0800
Subject: [PATCH] fix: add slippage clamping and improve WSOL wrap logic
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Changes to src/utils/calc/common.rs:
- Add MAX_SLIPPAGE_BASIS_POINTS constant (9999 = 99.99%)
- Clamp basis_points in calculate_with_slippage_buy to prevent amount doubling

Changes to src/instruction/pumpswap.rs:
- Fix WSOL wrap amount calculation for exact vs non-exact input modes
- Use input_amount for exact mode, sol_amount for non-exact mode

🤖 Generated with [Qoder][https://qoder.com]
---
 src/instruction/pumpswap.rs | 12 +++++++++++-
 src/utils/calc/common.rs    | 15 ++++++++++++++-
 2 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/src/instruction/pumpswap.rs b/src/instruction/pumpswap.rs
index a5fb596..1aa49b6 100755
--- a/src/instruction/pumpswap.rs
+++ b/src/instruction/pumpswap.rs
@@ -139,8 +139,18 @@ impl InstructionBuilder for PumpSwapInstructionBuilder {
         let mut instructions = Vec::with_capacity(6);
 
         if create_wsol_ata {
+            // Determine wrap amount based on instruction type:
+            // - buy_exact_quote_in: program spends exactly input_amount, wrap input_amount
+            // - buy: program may spend up to max_quote, wrap max_quote
+            let wrap_amount = if quote_is_wsol_or_usdc
+                && params.use_exact_sol_amount.unwrap_or(true)
+            {
+                params.input_amount.unwrap_or(0)
+            } else {
+                sol_amount
+            };
             instructions
-                .extend(crate::trading::common::handle_wsol(&params.payer.pubkey(), sol_amount));
+                .extend(crate::trading::common::handle_wsol(&params.payer.pubkey(), wrap_amount));
         }
 
         if params.create_output_mint_ata {
diff --git a/src/utils/calc/common.rs b/src/utils/calc/common.rs
index 32b65a0..e833acc 100644
--- a/src/utils/calc/common.rs
+++ b/src/utils/calc/common.rs
@@ -28,6 +28,10 @@ pub const fn ceil_div(a: u128, b: u128) -> u128 {
     (a + b - 1) / b
 }
 
+/// Maximum slippage in basis points (99.99% = 9999 bps)
+/// This prevents the wrap amount from doubling when slippage is 100%
+pub const MAX_SLIPPAGE_BASIS_POINTS: u64 = 9999;
+
 /// Calculate buy amount with slippage protection
 /// Add slippage percentage to the amount to ensure successful purchase
 ///
@@ -40,9 +44,18 @@ pub const fn ceil_div(a: u128, b: u128) -> u128 {
 /// * basis_points = 10  -> 0.1% slippage
 /// * basis_points = 100 -> 1% slippage
 /// * basis_points = 500 -> 5% slippage
+///
+/// # Note
+/// Basis points are clamped to MAX_SLIPPAGE_BASIS_POINTS (9999 = 99.99%)
+/// to prevent the amount from doubling when basis_points = 10000.
 #[inline(always)]
 pub const fn calculate_with_slippage_buy(amount: u64, basis_points: u64) -> u64 {
-    amount + (amount * basis_points / 10000)
+    let bps = if basis_points > MAX_SLIPPAGE_BASIS_POINTS {
+        MAX_SLIPPAGE_BASIS_POINTS
+    } else {
+        basis_points
+    };
+    amount + (amount * bps / 10000)
 }
 
 /// Calculate sell amount with slippage protection