fix(accounts): reject same-account internal transfers (#58529)

(cherry picked from commit 36a4dfe797)

# Conflicts:
#	erpnext/accounts/doctype/payment_entry/test_payment_entry.py

erpnext/accounts/doctype/payment_entry/payment_entry.js

@@ -45,23 +45,27 @@ frappe.ui.form.on("Payment Entry", {
 	},
 
 	setup: function (frm) {
-		frm.set_query("paid_from", function () {
+		frm.set_query("paid_from", function (doc) {
 			frm.events.validate_company(frm);
 
 			var account_types = ["Pay", "Internal Transfer"].includes(frm.doc.payment_type)
 				? ["Bank", "Cash"]
 				: [frappe.boot.party_account_types[frm.doc.party_type]];
+			let filters = {
+				account_type: ["in", account_types],
+				is_group: 0,
+				company: doc.company,
+			};
 
 			if (frm.doc.party_type == "Shareholder") {
 				account_types.push("Equity");
 			}
+			if (doc.payment_type == "Internal Transfer" && doc.paid_to) {
+				filters.name = ["!=", doc.paid_to];
+			}
 
 			return {
-				filters: {
-					account_type: ["in", account_types],
-					is_group: 0,
-					company: frm.doc.company,
-				},
+				filters,
 			};
 		});
 
@@ -105,21 +109,25 @@ frappe.ui.form.on("Payment Entry", {
 			}
 		});
 
-		frm.set_query("paid_to", function () {
+		frm.set_query("paid_to", function (doc) {
 			frm.events.validate_company(frm);
 
 			var account_types = ["Receive", "Internal Transfer"].includes(frm.doc.payment_type)
 				? ["Bank", "Cash"]
 				: [frappe.boot.party_account_types[frm.doc.party_type]];
+			let filters = {
+				account_type: ["in", account_types],
+				is_group: 0,
+				company: doc.company,
+			};
 			if (frm.doc.party_type == "Shareholder") {
 				account_types.push("Equity");
 			}
+			if (doc.payment_type == "Internal Transfer" && doc.paid_from) {
+				filters.name = ["!=", doc.paid_from];
+			}
 			return {
-				filters: {
-					account_type: ["in", account_types],
-					is_group: 0,
-					company: frm.doc.company,
-				},
+				filters,
 			};
 		});
 

erpnext/accounts/doctype/payment_entry/payment_entry.py

@@ -90,6 +90,7 @@ class PaymentEntry(AccountsController):
 		self.set_liability_account()
 		self.set_missing_ref_details(force=True)
 		self.validate_payment_type()
+		self.validate_internal_transfer_accounts()
 		self.validate_party_details()
 		self.set_exchange_rate()
 		self.validate_mandatory()
@@ -531,6 +532,10 @@ class PaymentEntry(AccountsController):
 		if self.payment_type not in ("Receive", "Pay", "Internal Transfer"):
 			frappe.throw(_("Payment Type must be one of Receive, Pay and Internal Transfer"))
 
+	def validate_internal_transfer_accounts(self):
+		if self.payment_type == "Internal Transfer" and self.paid_from and self.paid_from == self.paid_to:
+			frappe.throw(_("Paid From and Paid To accounts must be different for an Internal Transfer."))
+
 	def validate_party_details(self):
 		if self.party and not frappe.db.exists(self.party_type, self.party):
 			frappe.throw(_("{0} {1} does not exist").format(_(self.party_type), self.party))

erpnext/accounts/doctype/payment_entry/test_payment_entry.py

@@ -733,6 +733,23 @@ class TestPaymentEntry(FrappeTestCase):
 
 		self.validate_gl_entries(pe.name, expected_gle)
 
+	def test_internal_transfer_rejects_same_account(self):
+		pe = frappe.new_doc("Payment Entry")
+		pe.payment_type = "Internal Transfer"
+		pe.company = "_Test Company"
+		pe.paid_from = "_Test Bank - _TC"
+		pe.paid_to = "_Test Bank - _TC"
+		pe.paid_amount = 100
+		pe.received_amount = 100
+		pe.reference_no = "same-account-transfer"
+		pe.reference_date = nowdate()
+
+		self.assertRaisesRegex(
+			frappe.ValidationError,
+			"Paid From and Paid To accounts must be different",
+			pe.insert,
+		)
+
 	def test_payment_against_negative_sales_invoice(self):
 		si1 = create_sales_invoice()