fix: handle missing program_id in POS reward lines and update module documentation

README.md

@@ -1,15 +1,25 @@
 # POS Loyalty Safe Coupon Patch
 
-This custom Odoo module resolves a core Odoo 19 bug in the POS Loyalty module where standard Odoo code makes unsafe direct reads on `coupon_id.id` of reward lines.
+This custom Odoo module resolves critical Point of Sale (POS) Loyalty bugs in Odoo 19 that cause the POS UI to crash or render as a blank screen.
 
+## Unsafe Coupon Access Fix
 When an order is restored (e.g., during table switching in a restaurant) and references a coupon that is not yet fully loaded in the local client registry, Odoo leaves `coupon_id` as `undefined`. Accessing `.id` on this undefined object crashes the POS UI.
 
-## How it works
+**How it works:**
-Without modifying any core Odoo code, this module dynamically patches:
+* Dynamically patches `PosOrder.getLoyaltyPoints()`, `OrderPaymentValidation.validateOrder()`, and `PosStore.postProcessLoyalty()`.
-1. `PosOrder.getLoyaltyPoints()`
+* Temporarily mocks any missing `coupon_id` references with `{ id: 0 }`.
-2. `OrderPaymentValidation.validateOrder()`
+* Intercepts `this.data.call` during `postProcessLoyalty` to strip out dummy coupon records with ID `0` before communicating with the backend.
-3. `PosStore.postProcessLoyalty()`
 
-During their respective execution, it temporarily mocks any missing `coupon_id` references with `{ id: 0 }`. It also wraps `this.data.call` during `postProcessLoyalty` to ensure dummy coupon records with ID `0` are filtered out before being communicated back to the Odoo backend server. After execution, the original `undefined` state of the coupon is safely restored.
+---
+
+## Invalid/Archived Rewards & program_id Fix
+During startup or draft order restoration, if an existing order contains a reward line whose corresponding `reward_id` or `reward_id.program_id` is missing or archived (and therefore not loaded in the client registry), Odoo attempts to read `program_type` from it. This triggers a `TypeError: Cannot read properties of undefined (reading 'program_id')` or `(reading 'program_type')` and leaves a blank screen.
+
+**How it works:**
+* Dynamically patches `PosOrder._updateRewardLines()` and `PosStore.orderUpdateLoyaltyPrograms()`.
+* Automatically filters and deletes reward lines that are missing a valid `reward_id` or its associated `program_id`.
+* Restores non-corrupted order lines, safely healing the order state and allowing the POS session to load successfully.
+
+---
 
 This ensures zero side effects, maximum stability, and clean compatibility with standard/custom addons.

static/src/app/pos_loyalty_safe_coupon_patch.js

@@ -22,7 +22,7 @@ patch(PosOrder.prototype, {
     },
     _updateRewardLines() {
         if (this.lines) {
-            const invalidRewardLines = this.lines.filter((line) => line.is_reward_line && !line.reward_id);
+            const invalidRewardLines = this.lines.filter((line) => line.is_reward_line && (!line.reward_id || !line.reward_id.program_id));
             for (const line of invalidRewardLines) {
                 line.delete();
             }
@@ -84,7 +84,7 @@ patch(PosStore.prototype, {
     async orderUpdateLoyaltyPrograms() {
         const order = this.getOrder();
         if (order && order.lines) {
-            const invalidRewardLines = order.lines.filter((line) => line.is_reward_line && !line.reward_id);
+            const invalidRewardLines = order.lines.filter((line) => line.is_reward_line && (!line.reward_id || !line.reward_id.program_id));
             for (const line of invalidRewardLines) {
                 line.delete();
             }