pos/pos_supplierinfo_barcode/models/product.py

import json
from odoo import models, fields, api


class ProductTemplate(models.Model):
    _inherit = 'product.template'

    # technical field used in POS frontend
    supplier_barcode_json = fields.Char(
        "Supplier barcode list", readonly=True,
        compute="_compute_supplier_barcode_json")

    @api.multi
    def _compute_supplier_barcode_json(self):
        for t in self:
            supplier_barcode_json = [x for x in t.mapped('seller_ids.barcode') if x]
            t.supplier_barcode_json = json.dumps(supplier_barcode_json)