fix: convert default_item_manufacturer to link field (#30835) (#30866)

(cherry picked from commit dcda55641b)

Co-authored-by: Ankush Menat <ankush@frappe.io>

erpnext/patches.txt

@@ -358,6 +358,7 @@ erpnext.patches.v13_0.rename_non_profit_fields
 erpnext.patches.v13_0.enable_ksa_vat_docs #1
 erpnext.patches.v13_0.create_gst_custom_fields_in_quotation
 erpnext.patches.v13_0.update_expense_claim_status_for_paid_advances
+erpnext.patches.v13_0.change_default_item_manufacturer_fieldtype
 erpnext.patches.v13_0.set_return_against_in_pos_invoice_references
 erpnext.patches.v13_0.copy_custom_field_filters_to_website_item
 erpnext.patches.v13_0.education_deprecation_warning

erpnext/patches/v13_0/change_default_item_manufacturer_fieldtype.py

@@ -0,0 +1,16 @@
+import frappe
+
+
+def execute():
+
+	# Erase all default item manufacturers that dont exist.
+	item = frappe.qb.DocType("Item")
+	manufacturer = frappe.qb.DocType("Manufacturer")
+
+	(
+		frappe.qb.update(item)
+		.set(item.default_item_manufacturer, None)
+		.left_join(manufacturer)
+		.on(item.default_item_manufacturer == manufacturer.name)
+		.where(manufacturer.name.isnull() & item.default_item_manufacturer.isnotnull())
+	).run()

erpnext/stock/doctype/item/item.json

@@ -918,8 +918,9 @@
   },
   {
    "fieldname": "default_item_manufacturer",
-   "fieldtype": "Data",
+   "fieldtype": "Link",
    "label": "Default Item Manufacturer",
+   "options": "Manufacturer",
    "read_only": 1
   },
   {
@@ -954,7 +955,7 @@
  "image_field": "image",
  "index_web_pages_for_search": 1,
  "links": [],
- "modified": "2021-12-14 04:13:16.857534",
+ "modified": "2022-04-28 04:52:10.272256",
  "modified_by": "Administrator",
  "module": "Stock",
  "name": "Item",