Getting a KeyError when passing data to a Wizard in odoo 10

Question

i'm using a context to send data to my wizard, but i always get this error "KeyError: 'default_new_name"

i tried doing the example here but still getting the same error here's my code

model creating a wizard

@api.multi
def open_x2m_matrix(self):

    wiz = self.env['x2m.matrix.demo.wiz'].create({})
    return {
        'name': self.name,
        'type': 'ir.actions.act_window',
        'view_type': 'form',
        'view_mode': 'form',
        'res_model': 'x2m.matrix.demo.wiz',
        'target': 'new',
        'res_id': wiz.id,
        'context': self.env.context,
        'context': {'default_new_name': self.name},
    }

model creating 2d matrix

line_ids = fields.Many2many(
    'x2m.demo.line', default=lambda self: self._default_line_ids())
def _default_line_ids(self):
    recs =self.env['x2m.demo'].search([("name","!=",self._context['default_new_name'])])
    # same with users
    users = self.env['x2m.demo.line'].search([]).mapped('new_user_id')
    return [
        (0, 0, {
            'demo_id': rec.id,
            'new_user_id': usr.id,
            'value': 0,
        })
        # if the project doesn't have a task for the user, create a new one
        if not rec.line_ids.filtered(lambda x: x.new_user_id == usr) else
        # otherwise, return the task
        (4, rec.line_ids.filtered(lambda x: x.new_user_id == usr)[0].id)
        for rec in recs
        for usr in users
    ]

Answer 1

The create is already calling the default method for line_ids. So you should either don't create a wizard record and just call without an ID or you create it with your context flag on the right line:

1. open wizard without creating one

@api.multi
def open_x2m_matrix(self):
    context = dict(self.env.context or {})
    context.update({'default_new_name': self.name})
    return {
        'name': self.name,
        'type': 'ir.actions.act_window',
        'view_type': 'form',
        'view_mode': 'form',
        'res_model': 'x2m.matrix.demo.wiz',
        'target': 'new',
        # 'res_id': wiz.id,  # not needed
        'context': context
    }

2. use your context flag on creation, because that's the call where it's really needed

@api.multi
def open_x2m_matrix(self):

    wiz = self.env['x2m.matrix.demo.wiz'].with_context(
        default_new_name=self.name).create({})
    return {
        'name': self.name,
        'type': 'ir.actions.act_window',
        'view_type': 'form',
        'view_mode': 'form',
        'res_model': 'x2m.matrix.demo.wiz',
        'target': 'new',
        'res_id': wiz.id,
        'context': self.env.context,
    }