Issues

1. pos.globalState.get_cashier() is undefined:
   • The cashier object is populated only after the POS session is fully loaded and a user is logged in.
   • If you're patching getNumpadButtons() too early (before the cashier is set), the cashier object will be undefined.
2. Why the button shows for all or none:
   • Because you're relying on cashier.hasGroupDiscount, and if cashier is undefined, your fallback disables the logic or treats all users the same.

You should defer the permission check to runtime and not during the initial button setup, or ensure the cashier object is guaranteed to be available before patching.

Fix: Check cashier in setup() or use reactive model

Instead of patching getNumpadButtons(), consider overriding the setup() method and dynamically updating the button state once the cashier is available. Like this:

import { patch } from "@web/core/utils/patch";
import { ProductScreen } from "@point_of_sale/app/screens/product_screen/product_screen";

patch(ProductScreen.prototype, {
    setup() {
        super.setup();
        this.env.services.pos.bus.on('cashier-changed', null, () => {
            this.render(); // re-render when cashier changes
        });
    },

    get numpadButtons() {
        const buttons = super.numpadButtons;
        const cashier = this.env.services.pos.get_cashier?.() || null;
        const hasGroupDiscount = cashier?.hasGroupDiscount || false;

        return buttons.map(button => {
            if (["discount", "price"].includes(button.value)) {
                return {
                    ...button,
                    disabled: !hasGroupDiscount,
                };
            }
            return button;
        });
    },
});

Python Fix: Ensure field is loaded to POS user data

Your Python code seems mostly correct, but verify the custom group external ID is correct and ensure it's added to the loaded user data:

python
CopiarEditar
class ResUsers(models.Model):
    _inherit = 'res.users'

    def _load_pos_data(self, data):
        res = super()._load_pos_data(data)
        for record in res["data"]:
            user = self.browse(record["id"])
            record["hasGroupDiscount"] = user.has_group('pos_access_right.group_discount')
        return res

Also, confirm that hasGroupDiscount is being passed to the JS frontend via the POS session config and is accessible in the cashier object.

Group Access Configuration

Make sure:

• Your custom group group_discount exists and has the correct external ID (pos_access_right.group_discount).
• POS users are correctly added to the group via Settings > Users > Access Rights.