feat: auto-fill subscription accounting dimensions from plan with item fallback (#57615)

When a plan is selected in the Subscription's Plans table, the Subscription's
accounting dimensions (cost center and any custom dimensions) auto-fill from the
plan, falling back to the plan item's company default (selling cost center for a
Customer, buying for a Supplier). Only empty fields are filled. Stale async
responses are ignored so a quick re-pick of the plan can't be overwritten.

erpnext/accounts/doctype/subscription/subscription.js

@@ -110,6 +110,32 @@ frappe.ui.form.on("Subscription", {
 	},
 });
 
+frappe.ui.form.on("Subscription Plan Detail", {
+	plan: function (frm, cdt, cdn) {
+		const row = locals[cdt][cdn];
+		if (!row.plan) return;
+		const requested_plan = row.plan;
+
+		frappe.call({
+			method: "erpnext.accounts.doctype.subscription.subscription.get_plan_dimensions",
+			args: {
+				plan: requested_plan,
+				company: frm.doc.company,
+				party_type: frm.doc.party_type,
+			},
+			callback: function (r) {
+				if (!r.message || locals[cdt]?.[cdn]?.plan !== requested_plan) return;
+				// Only fill dimensions left empty, so a manual entry or an earlier plan is never overwritten.
+				for (const [dimension, value] of Object.entries(r.message)) {
+					if (frm.fields_dict[dimension] && !frm.doc[dimension]) {
+						frm.set_value(dimension, value);
+					}
+				}
+			},
+		});
+	},
+});
+
 // Status -> colour and label for the calendar heatmap. Keys are Title-case to
 // match the value frappe-charts shows in its hover tooltip.
 const HEATMAP_COLORS = {

erpnext/accounts/doctype/subscription/subscription.py

@@ -26,6 +26,7 @@ from erpnext.accounts.doctype.accounting_dimension.accounting_dimension import (
 	get_accounting_dimensions,
 )
 from erpnext.accounts.doctype.subscription_plan.subscription_plan import get_plan_rate
+from erpnext.stock.doctype.item.item import get_item_defaults
 
 
 class InvoiceCancelled(frappe.ValidationError):
@@ -981,6 +982,39 @@ def get_prorata_factor(
 	return diff / plan_days
 
 
+@frappe.whitelist()
+def get_plan_dimensions(
+	plan: str, company: str | None = None, party_type: str | None = None
+) -> dict[str, str]:
+	"""Resolve a plan's accounting dimensions, falling back to the plan item's company defaults."""
+	plan_doc = frappe.get_cached_doc("Subscription Plan", plan)
+
+	dimensions = {}
+	for dimension in ["cost_center", *get_accounting_dimensions()]:
+		value = plan_doc.get(dimension) or get_item_dimension(plan_doc.item, dimension, company, party_type)
+		if value:
+			dimensions[dimension] = value
+
+	return dimensions
+
+
+def get_item_dimension(
+	item_code: str, dimension: str, company: str | None, party_type: str | None
+) -> str | None:
+	if not company:
+		return None
+
+	item_defaults = get_item_defaults(item_code, company)
+	if dimension != "cost_center":
+		return item_defaults.get(dimension)
+
+	selling = item_defaults.get("selling_cost_center")
+	buying = item_defaults.get("buying_cost_center")
+	if party_type == PARTY_SUPPLIER:
+		return buying or selling
+	return selling or buying
+
+
 def process_all(subscription: list, posting_date: DateTimeLikeObject | None = None) -> None:
 	"""
 	Task to updates the status of all `Subscription` apart from those that are cancelled

erpnext/accounts/doctype/subscription/test_subscription.py

@@ -18,7 +18,12 @@ from frappe.utils.data import (
 )
 
 from erpnext.accounts.doctype.payment_entry.payment_entry import get_payment_entry
-from erpnext.accounts.doctype.subscription.subscription import Subscription, get_prorata_factor, process_all
+from erpnext.accounts.doctype.subscription.subscription import (
+	Subscription,
+	get_plan_dimensions,
+	get_prorata_factor,
+	process_all,
+)
 from erpnext.accounts.utils import update_subscription_on_invoice_update
 from erpnext.tests.utils import ERPNextTestSuite
 
@@ -951,6 +956,47 @@ class TestSubscription(ERPNextTestSuite):
 		cells = {cell["date"]: cell for cell in subscription.get_billing_heatmap()}
 		self.assertEqual(cells[str(getdate(invoice.from_date))]["status"], "refunded")
 
+	def test_plan_dimensions_resolve_from_plan_then_item(self):
+		from erpnext.stock.doctype.item.test_item import make_item
+
+		# Plan-level cost center takes precedence.
+		create_plan(plan_name="_Test Sub Plan CC", cost=100, currency="INR")
+		frappe.db.set_value(
+			"Subscription Plan", "_Test Sub Plan CC", "cost_center", "_Test Cost Center - _TC"
+		)
+		self.assertEqual(
+			get_plan_dimensions("_Test Sub Plan CC", "_Test Company", "Customer").get("cost_center"),
+			"_Test Cost Center - _TC",
+		)
+
+		# No plan cost center: fall back to the item's company default (selling vs buying by party type).
+		item = make_item(
+			"_Test Sub Dimension Item",
+			{
+				"is_stock_item": 0,
+				"item_defaults": [
+					{
+						"company": "_Test Company",
+						"selling_cost_center": "_Test Cost Center - _TC",
+						"buying_cost_center": "_Test Cost Center 2 - _TC",
+					}
+				],
+			},
+		)
+		create_plan(plan_name="_Test Sub Plan No CC", cost=100, currency="INR", item=item.name)
+
+		self.assertEqual(
+			get_plan_dimensions("_Test Sub Plan No CC", "_Test Company", "Customer").get("cost_center"),
+			"_Test Cost Center - _TC",
+		)
+		self.assertEqual(
+			get_plan_dimensions("_Test Sub Plan No CC", "_Test Company", "Supplier").get("cost_center"),
+			"_Test Cost Center 2 - _TC",
+		)
+
+		# Without a company the item fallback is skipped.
+		self.assertNotIn("cost_center", get_plan_dimensions("_Test Sub Plan No CC"))
+
 
 def make_full_credit_note(invoice_name):
 	from erpnext.accounts.doctype.sales_invoice.mapper import make_sales_return