Fix auto pricing overwriting manual purchase price #10846 (#11411)

* Fix auto pricing overwriting manual purchase price #10846

* Added entry to api_version.py

---------

Co-authored-by: Oliver <oliver.henry.walters@gmail.com>

src/backend/InvenTree/InvenTree/api_version.py

@@ -1,13 +1,16 @@
 """InvenTree API version information."""
 
 # InvenTree API version
-INVENTREE_API_VERSION = 458
+INVENTREE_API_VERSION = 459
 """Increment this API version number whenever there is a significant change to the API that any clients need to know about."""
 
 INVENTREE_API_TEXT = """
 
+v459 -> 2026-02-23 : https://github.com/inventree/InvenTree/pull/11411
+    - Changed PurchaseOrderLine "auto_pricing" default value from true to false
+
 v458 -> 2026-02-22 : https://github.com/inventree/InvenTree/pull/11401
-    - siwtches token refresh endpoint to use POST instead of GET (upstream allauth change)
+    - Switches token refresh endpoint to use POST instead of GET (upstream allauth change)
 
 v457 -> 2026-02-11 : https://github.com/inventree/InvenTree/pull/10887
     - Extend the "auto allocate" wizard API to include tracked items

src/backend/InvenTree/order/serializers.py

@@ -639,7 +639,7 @@ class PurchaseOrderLineItemSerializer(
         help_text=_(
             'Automatically calculate purchase price based on supplier part data'
         ),
-        default=True,
+        default=False,
     )
 
     destination_detail = enable_filter(

src/frontend/src/forms/PurchaseOrderForms.tsx

@@ -113,16 +113,6 @@ export function usePurchaseOrderLineItemFields({
     }
   }, [create, part, quantity, priceBreaks]);
 
-  useEffect(() => {
-    if (autoPricing) {
-      setPurchasePrice('');
-    }
-  }, [autoPricing]);
-
-  useEffect(() => {
-    setAutoPricing(purchasePrice === '');
-  }, [purchasePrice]);
-
   const fields = useMemo(() => {
     const fields: ApiFormFieldSet = {
       order: {
@@ -159,6 +149,7 @@ export function usePurchaseOrderLineItemFields({
       purchase_price: {
         icon: <IconCurrencyDollar />,
         value: purchasePrice,
+        disabled: autoPricing,
         placeholder: suggestedPurchasePrice,
         placeholderAutofill: true,
         onValueChange: setPurchasePrice
@@ -169,6 +160,7 @@ export function usePurchaseOrderLineItemFields({
         onValueChange: setPurchasePriceCurrency
       },
       auto_pricing: {
+        default: create !== false,
         value: autoPricing,
         onValueChange: setAutoPricing
       },