fix: fetch correct item tax template on item rate update (#47955)

erpnext/public/js/controllers/transaction.js

@@ -44,23 +44,22 @@ erpnext.TransactionController = class TransactionController extends erpnext.taxe
 
 			if (item.item_code && item.rate) {
 				frappe.call({
-					method: "frappe.client.get_value",
+					method: "erpnext.stock.get_item_details.get_item_tax_template",
 					args: {
-						doctype: "Item Tax",
-						parent: "Item",
-						filters: {
-							parent: item.item_code,
-							minimum_net_rate: ["<=", item.rate],
-							maximum_net_rate: [">=", item.rate]
-						},
-						fieldname: "item_tax_template"
+						ctx: {
+							item_code: item.item_code,
+							company: frm.doc.company,
+							base_net_rate: item.base_net_rate,
+							tax_category: frm.doc.tax_category,
+							item_tax_template: item.item_tax_template,
+							posting_date: frm.doc.posting_date,
+							bill_date: frm.doc.bill_date,
+							transaction_date: frm.doc.transaction_date,
+						}
 					},
 					callback: function(r) {
-						const tax_rule = r.message;
-
-						let matched_template = tax_rule ? tax_rule.item_tax_template : null;
-
-						frappe.model.set_value(cdt, cdn, 'item_tax_template', matched_template);
+						const item_tax_template = r.message;
+						frappe.model.set_value(cdt, cdn, 'item_tax_template', item_tax_template);
 					}
 				});
 			}

erpnext/stock/get_item_details.py

@@ -672,8 +672,9 @@ def get_item_tax_info(doc, tax_category, item_codes, item_rates=None, item_tax_t
 	return out
 
 
+@frappe.whitelist()
 @erpnext.normalize_ctx_input(ItemDetailsCtx)
-def get_item_tax_template(ctx: ItemDetailsCtx, item, out: ItemDetails):
+def get_item_tax_template(ctx: ItemDetailsCtx, item=None, out: ItemDetails | None = None):
 	"""
 	Determines item_tax template from item or parent item groups.
 
@@ -691,6 +692,12 @@ def get_item_tax_template(ctx: ItemDetailsCtx, item, out: ItemDetails):
 	        "base_net_rate": float
 	        }
 	"""
+	if not item:
+		if not ctx.get("item_code"):
+			frappe.throw(_("Item/Item Code required to get Item Tax Template."))
+		else:
+			item = frappe.get_cached_doc("Item", ctx.item_code)
+
 	item_tax_template = None
 	if item.taxes:
 		item_tax_template = _get_item_tax_template(ctx, item.taxes, out)
@@ -702,9 +709,11 @@ def get_item_tax_template(ctx: ItemDetailsCtx, item, out: ItemDetails):
 			item_tax_template = _get_item_tax_template(ctx, item_group_doc.taxes, out)
 			item_group = item_group_doc.parent_item_group
 
-	if ctx.get("child_doctype") and item_tax_template:
+	if out and ctx.get("child_doctype") and item_tax_template:
 		out.update(get_fetch_values(ctx.get("child_doctype"), "item_tax_template", item_tax_template))
 
+	return item_tax_template
+
 
 @erpnext.normalize_ctx_input(ItemDetailsCtx)
 def _get_item_tax_template(