Hi all, I'm current facing a issue on re-define fields when doing inheritance.

my code is like below:

PY file

class expenseNew(models.Model):

    _name = 'expense_new.expense_new'

    _inherits = { 'hr.expense':'expense_new_id' }

    expense_new_id = fields.Many2one('hr.expense', help="This is a many2one field in expense_new module, and this field is used as a link to hr.expense module")

    name = fields.Char(string='Expense Summary', readonly=True, required=True, states={'draft': [('readonly', False)], 'refused': [('readonly', False)]})

XML file

<div class="oe_title">    
    <label for="name"/>    
    <h1>        
    <field name="name" placeholder="e.g. Lunch with Customer"/>    
    </h1>
</div>

<record id="expense_new_form_view" model="ir.ui.view">
<field name="name">expense_new.expense_new.form.view</field>
<field name="model">expense_new.expense_new</field>
<field name="arch" type="xml">
<form string="Expenses" class="o_expense_form">
    <header> ...... </header>
    <sheet>
        <div class="oe_title">
            <label for="name"/>
            <h1>
                <field name="name" placeholder="e.g. Lunch with Customer"/>
            </h1>
        </div>
        ......

default PY file

name = fields.Char(string='Expense Description', readonly=True, required=True, states={'draft': [('readonly', False)], 'refused': [('readonly', False)]})

As you can see, compare to default, what I only changed is "string" attribute.

This code gives me following error message.

The operation cannot be completed, probably due to the following:

- deletion: you may be trying to delete a record while other records still reference it

- creation/update: a mandatory field is not correctly set

[object with reference: name - name]

If I delete my re-define field "name" in my PY file, error disappear. But this is the correct way to overwrite original field, am I right? Or can someone point out what I missed? BTW, on the 

Any help will be useful! Thanks a lot!