From cbfe646ce14d8436adbaa72cda95d38e6cdcd908 Mon Sep 17 00:00:00 2001
From: "Carlos R. L. Rodrigues"
 <37986729+carlos-r-l-rodrigues@users.noreply.github.com>
Date: Fri, 15 Aug 2025 11:43:52 -0300
Subject: [PATCH] chore(utils): round to zero credit lines (#13200)

---
 .changeset/lovely-tips-know.md                     |  5 +++++
 .../core/utils/src/totals/credit-lines/index.ts    |  9 +++++----
 packages/core/utils/src/totals/promotion/index.ts  | 14 ++++++++++++--
 3 files changed, 22 insertions(+), 6 deletions(-)
 create mode 100644 .changeset/lovely-tips-know.md

diff --git a/.changeset/lovely-tips-know.md b/.changeset/lovely-tips-know.md
new file mode 100644
index 0000000000..656753fde7
--- /dev/null
+++ b/.changeset/lovely-tips-know.md
@@ -0,0 +1,5 @@
+---
+"@medusajs/utils": patch
+---
+
+chore(utils): round to zero promotions and credit lines
diff --git a/packages/core/utils/src/totals/credit-lines/index.ts b/packages/core/utils/src/totals/credit-lines/index.ts
index fd05eb62fa..ac17217637 100644
--- a/packages/core/utils/src/totals/credit-lines/index.ts
+++ b/packages/core/utils/src/totals/credit-lines/index.ts
@@ -1,7 +1,7 @@
 import { BigNumberInput } from "@medusajs/types"
 import { isDefined } from "../../common"
 import { BigNumber } from "../big-number"
-import { MathBN } from "../math"
+import { MathBN, MEDUSA_EPSILON } from "../math"
 
 export function calculateCreditLinesTotal({
   creditLines,
@@ -46,9 +46,10 @@ export function calculateCreditLinesTotal({
     }
   }
 
+  const isZero = MathBN.lte(creditLinesTotal, MEDUSA_EPSILON)
   return {
-    creditLinesTotal,
-    creditLinesSubtotal,
-    creditLinesTaxTotal,
+    creditLinesTotal: isZero ? MathBN.convert(0) : creditLinesTotal,
+    creditLinesSubtotal: isZero ? MathBN.convert(0) : creditLinesSubtotal,
+    creditLinesTaxTotal: isZero ? MathBN.convert(0) : creditLinesTaxTotal,
   }
 }
diff --git a/packages/core/utils/src/totals/promotion/index.ts b/packages/core/utils/src/totals/promotion/index.ts
index eabfe0ee6c..14f9ce6c1f 100644
--- a/packages/core/utils/src/totals/promotion/index.ts
+++ b/packages/core/utils/src/totals/promotion/index.ts
@@ -108,7 +108,12 @@ export function calculateAdjustmentAmountFromPromotion(
       lineItemsAmount
     )
 
-    return MathBN.min(promotionValue, applicableAmount)
+    const returnValue = MathBN.min(promotionValue, applicableAmount)
+    if (MathBN.lte(returnValue, MEDUSA_EPSILON)) {
+      return MathBN.convert(0)
+    }
+
+    return returnValue
   }
 
   /*
@@ -157,5 +162,10 @@ export function calculateAdjustmentAmountFromPromotion(
     lineItemsAmount
   )
 
-  return MathBN.min(promotionValue, applicableAmount)
+  const returnValue = MathBN.min(promotionValue, applicableAmount)
+  if (MathBN.lte(returnValue, MEDUSA_EPSILON)) {
+    return MathBN.convert(0)
+  }
+
+  return returnValue
 }