//Code 1//

# -*- coding: utf-8 -*-
from odoo import api, fields, models, _

class ProductProduct(models.Model):
_inherit = "product.product"

# New field to define the maximum quantity limit for a product in POS.
pos_product_qty_limit = fields.Integer("POS Product Quantity Limit")

//Code 2//

# -*- coding: utf-8 -*-
from odoo import models

class PosSession(models.Model):
_inherit = "pos.session"

def _loader_params_product_product(self):
"""
This method customizes the loader parameters for loading product data in a POS session.
Specifically, it ensures that the `pos_product_qty_limit` field is included
when product data is loaded into the POS interface.
"""
result = super()._loader_params_product_product()

# Add the `pos_product_qty_limit` field to the list of fields to be loaded.
result["search_params"]["fields"].extend(["pos_product_qty_limit"])

return result

//Code 3//

/* @odoo-module */

import { patch } from "@web/core/utils/patch";
import { Order } from "@point_of_sale/app/store/models";
import { ErrorPopup } from "@point_of_sale/app/errors/popups/error_popup";
import { _t } from "@web/core/l10n/translation";

// Patch the Order model to include quantity validation during payment.
patch(Order.prototype, {
/**
* Override the `pay` method to include custom validation logic for product quantity limits.
* This ensures that users cannot pay for an order if any product's quantity exceeds its defined limit.
*/
async pay() {
const orderLines = this.get_orderlines();

for (const line of orderLines) {
const posProductQtyLimit = line.product.pos_product_qty_limit;
// Check if the quantity exceeds the limit.
if (posProductQtyLimit > 0 && line.quantity > posProductQtyLimit) {
// Display a warning popup if the limit is exceeded.
this.env.services.popup.add(ErrorPopup, {
title: _t("Product Quantity Exceeded"),
body: _t(`The quantity for the product "${line.product.display_name}" exceeds the limit. You cannot add a quantity greater than "${posProductQtyLimit}".`),
});
return;
}
}
return super.pay(...arguments);
},
});