Hello, Vincent

This the example with 14.0 where you can find the link stock.move in account.move having stock_move_id and from there picking reference is there.

Code:

num_picking = fields.Char(compute = '_find_picking_number', store=True)

@api.depends('move_id', 'move_id.stock_move_id', 'move_id.stock_move_id.picking_id')

def _find_picking_number(self):

    for line in self:

        line.num_picking = line.move_id.stock_move_id.picking_id.name if line.move_id and         line.move_id.stock_move_id else False

Thanks..

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