first commit

__manifest__.py

@@ -19,6 +19,7 @@ account payable.
         'data/account_payment_method_data.xml',
         'views/account_batch_payment_views.xml',
         'views/account_payment_views.xml',
+        'views/account_payment_register_views.xml',
     ],
     'installable': True,
     'application': False,

models/__init__.py

@@ -1,3 +1,4 @@
 # -*- coding: utf-8 -*-
 from . import account_batch_payment
-from . import account_payment
+from . import account_payment
+from . import account_payment_register

models/account_payment_register.py

@@ -0,0 +1,45 @@
+# -*- coding: utf-8 -*-
+from odoo import models, fields, api, _
+
+
+class AccountPaymentRegister(models.TransientModel):
+    _inherit = "account.payment.register"
+
+    # Add expense account field to payment register wizard
+    expense_account_id = fields.Many2one(
+        'account.account',
+        string='Expense Account',
+        domain="[('account_type', 'not in', ('asset_receivable', 'liability_payable'))]",
+        help="Account used for expense instead of the default payable/receivable account"
+    )
+
+    @api.depends('journal_id', 'partner_type', 'is_internal_transfer', 'destination_journal_id', 'expense_account_id')
+    def _compute_destination_account_id(self):
+        ''' Override to use expense account if defined '''
+        super()._compute_destination_account_id()
+        for pay in self:
+            # If we have an expense account, use it instead of the default payable/receivable account
+            if pay.expense_account_id and ((pay.payment_type == 'outbound' and pay.partner_type == 'supplier') or
+                                          (pay.payment_type == 'inbound' and pay.partner_type == 'customer')):
+                pay.destination_account_id = pay.expense_account_id
+
+    def _create_payment_vals_from_wizard(self, batch_result):
+        ''' Override to use expense account if defined '''
+        payment_vals = super()._create_payment_vals_from_wizard(batch_result)
+        
+        # If we have an expense account, replace the destination account
+        if self.expense_account_id and len(payment_vals.get('line_ids', [])) >= 2:
+            # The second line is typically the counterpart line (payable/receivable)
+            payment_vals['line_ids'][1]['account_id'] = self.expense_account_id.id
+            
+        return payment_vals
+
+    def _create_payment_vals_from_batch(self, batch_result):
+        ''' Override to use expense account if defined '''
+        payment_vals = super()._create_payment_vals_from_batch(batch_result)
+        
+        # If we have an expense account, replace the destination account
+        if self.expense_account_id:
+            payment_vals['destination_account_id'] = self.expense_account_id.id
+            
+        return payment_vals

views/__init__.py

@@ -1 +1,4 @@
-# -*- coding: utf-8 -*-
+# -*- coding: utf-8 -*-
+from . import account_batch_payment_views
+from . import account_payment_views
+from . import account_payment_register_views

views/account_payment_register_views.xml

@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="utf-8"?>
+<odoo>
+    <record id="view_account_payment_register_form_inherit" model="ir.ui.view">
+        <field name="name">account.payment.register.form.inherit</field>
+        <field name="model">account.payment.register</field>
+        <field name="inherit_id" ref="account.view_account_payment_register_form"/>
+        <field name="arch" type="xml">
+            <xpath expr="//group[@name='group1']" position="inside">
+                <field name="expense_account_id"
+                       invisible="(partner_type != 'supplier' or payment_type != 'outbound') and (partner_type != 'customer' or payment_type != 'inbound')"
+                       domain="[('account_type', 'not in', ('asset_receivable', 'liability_payable'))]"/>
+            </xpath>
+        </field>
+    </record>
+</odoo>