Merge pull request #57697 from frappe/mergify/bp/version-16-hotfix/pr-57674

fix: preserve UOM conversion factor precision in transactions (backport #57674)

erpnext/controllers/buying_controller.py

@@ -467,7 +467,7 @@ class BuyingController(SubcontractingController):
 					self.precision("item_tax_amount", item),
 				)
 
-				self.round_floats_in(item)
+				self.round_floats_in(item, do_not_round_fields=["conversion_factor"])
 				if flt(item.conversion_factor) == 0.0:
 					item.conversion_factor = (
 						get_conversion_factor(item.item_code, item.uom).get("conversion_factor") or 1.0

erpnext/controllers/taxes_and_totals.py

@@ -227,7 +227,12 @@ class calculate_taxes_and_totals:
 		if self.doc.get("is_consolidated") or self.discount_amount_applied:
 			return
 
-		do_not_round_fields = ["valuation_rate", "incoming_rate", "sales_incoming_rate"]
+		do_not_round_fields = [
+			"valuation_rate",
+			"incoming_rate",
+			"sales_incoming_rate",
+			"conversion_factor",
+		]
 		for item in self.doc.items:
 			self.doc.round_floats_in(item, do_not_round_fields=do_not_round_fields)
 			self.calculate_item_rate(item)

erpnext/public/js/controllers/taxes_and_totals.js

@@ -138,11 +138,26 @@ erpnext.taxes_and_totals = class TaxesAndTotals extends erpnext.payments {
 		}
 	}
 
+	get_item_fields_to_round() {
+		const [item] = this.frm.doc.items || [];
+		if (!item) {
+			return [];
+		}
+
+		const do_not_round_fields = ["conversion_factor"];
+		return frappe.meta
+			.get_fieldnames(item.doctype, item.parent, {
+				fieldtype: ["in", ["Currency", "Float"]],
+			})
+			.filter((fieldname) => !do_not_round_fields.includes(fieldname));
+	}
+
 	calculate_item_values() {
 		var me = this;
 		if (!this.discount_amount_applied) {
+			const fields_to_round = this.get_item_fields_to_round();
 			for (const item of this.frm.doc.items || []) {
-				frappe.model.round_floats_in(item);
+				frappe.model.round_floats_in(item, fields_to_round);
 				item.net_rate = item.rate;
 				item.qty = item.qty === undefined ? (me.frm.doc.is_return ? -1 : 1) : item.qty;
 

erpnext/stock/doctype/material_request/test_material_request.py

@@ -847,6 +847,28 @@ class TestMaterialRequest(ERPNextTestSuite):
 		mr = frappe.get_doc("Material Request", mr.name)
 		self.assertEqual(mr.per_ordered, 100)
 
+	def test_fractional_conversion_factor_for_purchase(self):
+		item = create_item("_Test Fractional Conversion Item", stock_uom="Kg", is_purchase_item=1)
+		conversion_factor = 0.453592292
+
+		mr = make_material_request(
+			item_code=item.name,
+			qty=1000,
+			uom="Pound",
+			conversion_factor=conversion_factor,
+		)
+		mr.reload()
+
+		self.assertEqual(mr.items[0].conversion_factor, conversion_factor)
+
+		po = make_purchase_order(mr.name)
+		po.supplier = "_Test Supplier"
+		po.insert()
+		po.reload()
+
+		self.assertEqual(po.items[0].conversion_factor, conversion_factor)
+		self.assertEqual(po.items[0].stock_qty, mr.items[0].stock_qty)
+
 	def test_customer_provided_parts_mr(self):
 		create_item("CUST-0987", is_customer_provided_item=1, customer="_Test Customer", is_purchase_item=0)
 		existing_requested_qty = self._get_requested_qty("_Test Customer", "_Test Warehouse - _TC")