[IMP] account, usability: improved account.move form view

* proposal of the next line debit/credit
* name of account.move.line isn't required anymore, but reference of account.move is

addons/account/models/account_move.py

@@ -369,7 +369,7 @@ class AccountMoveLine(models.Model):
             counterpart = list(counterpart)[0:2] + ["..."]
         self.counterpart = ",".join(counterpart)
 
-    name = fields.Char(required=True, string="Label")
+    name = fields.Char(string="Label")
     quantity = fields.Float(digits=(16, 2),
         help="The optional quantity expressed by this line, eg: number of product sold. The quantity is not a legal requirement but is very useful for some reports.")
     product_uom_id = fields.Many2one('product.uom', string='Unit of Measure')
@@ -434,6 +434,23 @@ class AccountMoveLine(models.Model):
         ('credit_debit2', 'CHECK (credit+debit>=0)', 'Wrong credit or debit value in accounting entry !'),
     ]
 
+    @api.model
+    def default_get(self, fields):
+        rec = super(AccountMoveLine, self).default_get(fields)
+        if 'line_ids' not in self._context:
+            return rec
+
+        #compute the default credit/debit of the next line in case of a manual entry
+        balance = 0
+        for line in self._context['line_ids']:
+            if line[2]:
+                balance += line[2]['debit'] - line[2]['credit']
+        if balance < 0:
+            rec.update({'debit': -balance})
+        if balance > 0:
+            rec.update({'credit': balance})
+        return rec
+
     @api.multi
     @api.constrains('currency_id', 'account_id')
     def _check_currency(self):

addons/account/views/account_view.xml

@@ -1299,7 +1299,7 @@
                             <field name="date"/>
                         </group>
                         <group>
-                            <field name="ref"/>
+                            <field name="ref" required="1"/>
                             <field name="company_id" required="1" groups="base.group_multi_company"/>
                             <field name="amount" invisible="1"/>
                             <field name="currency_id" invisible="1"/>