refactor!: store item wise tax details as a more flexible dict

erpnext/patches/v15_0/migrate_old_item_wise_tax_data_format.py

@@ -0,0 +1,59 @@
+import json
+
+import frappe
+from frappe.utils import flt
+
+from erpnext.controllers.taxes_and_totals import ItemWiseTaxDetail
+
+
+def execute():
+	# Get all DocTypes that have the 'item_wise_tax_details' field
+	doctypes_with_tax_details = frappe.get_all(
+		"DocField", filters={"fieldname": "item_wise_tax_details"}, fields=["parent"], pluck="parent"
+	)
+	for doctype in doctypes_with_tax_details:
+		# Get all documents of this DocType that have data in 'item_wise_tax_details'
+		docs = frappe.get_all(
+			doctype,
+			filters={"item_wise_tax_details": ["is", "set"]},
+			fields=["name", "item_wise_tax_details"],
+		)
+		for doc in docs:
+			if not doc.item_wise_tax_details:
+				continue
+
+			updated_tax_details = {}
+			needs_update = False
+
+			for item, tax_data in json.loads(doc.item_wise_tax_details).items():
+				if isinstance(tax_data, list) and len(tax_data) == 2:
+					updated_tax_details[item] = ItemWiseTaxDetail(
+						tax_rate=tax_data[0],
+						tax_amount=tax_data[1],
+						# can't be reliably reconstructed since it depends on the tax type
+						# (actual, net, previous line total, previous line net, etc)
+						net_amount=0.0,
+					)
+					needs_update = True
+				elif isinstance(tax_data, str):
+					updated_tax_details[item] = ItemWiseTaxDetail(
+						tax_rate=flt(tax_data),
+						tax_amount=0.0,
+						net_amount=0.0,
+					)
+					needs_update = True
+				else:
+					updated_tax_details[item] = tax_data
+
+			if needs_update:
+				frappe.db.set_value(
+					doctype,
+					doc.name,
+					"item_wise_tax_details",
+					json.dumps(updated_tax_details),
+					update_modified=False,
+				)
+
+		frappe.db.commit()
+
+	print("Migration of old item-wise tax data format completed for all relevant DocTypes.")