Quote from jgrant@spiritualme.life on July 24, 2026, 20:13

# Bug report — WooCommerce Currency Switcher (FOX) 2.5.0

**To:** PluginUS support / CodeCanyon item support
**Severity:** Critical — breaks WooCommerce checkout completion on any site with HPOS disabled
**Affected version:** 2.5.0 (2.4.x not affected)

---

## Summary

In 2.5.0, `WOOCS::woocommerce_get_order_currency()` causes **infinite recursion** whenever an order object's currency is read on the front end and **HPOS (High-Performance Order Storage) is disabled**.

The practical effect: the WooCommerce **order-received / "Thank you" page returns HTTP 500**. The order and payment complete correctly, but the customer sees *"There has been a critical error on this website."* instead of confirmation — so customers believe their purchase failed.

## Environment

| | |
|---|---|
| FOX version | 2.5.0 (regression; 2.4.x unaffected) |
| WooCommerce | 10.9.4 |
| WordPress | 6.9.5 |
| PHP | 8.3 |
| **HPOS** | **disabled** (`woocommerce_custom_orders_table_enabled = no`; 532 orders in legacy `wp_posts` storage) |
| Other | WPML multi-currency in use |

## Root cause

`classes/woocs.php` line 379 registers a handler on the order-currency filter:

```php
add_action( 'woocommerce_order_get_currency', array( $this, 'woocommerce_get_order_currency' ), 1, 2 );
```

The handler (line 3629) contains an **HPOS early-return guard**, then calls `$order->get_currency()`:

```php
public function woocommerce_get_order_currency( $order_currency, $order ) {
// HPOS
if ( $this->woocs_hpos->isEnabledHpos() ) {
return $order_currency; // <-- guarded path, no recursion
}

if ( ! wp_doing_ajax() and ! is_admin() and is_object( $order ) ) {
...
$currency = $order ? $order->get_currency() : get_post_meta( $order_id, '_order_currency', true );
// ^^^^^^^^^^^^^^^^^^^^^ re-fires the very filter we are inside
...
}

return $order_currency;
}
```

`WC_Abstract_Order::get_currency()` → `WC_Data::get_prop()` → `apply_filters( 'woocommerce_order_get_currency', ... )` → **this same handler again**, with no recursion guard.

**When HPOS is enabled the early return prevents this**, which is presumably why it was not caught in testing. With HPOS disabled the guard is skipped and the call recurses until the process dies.

## Observed stack (repeating 4-frame cycle)

```
#0 woocommerce/includes/abstracts/abstract-wc-data.php(939): WC_Data->get_hook_prefix()
#1 woocommerce/includes/abstracts/abstract-wc-order.php(346): WC_Data->get_prop()
#2 woocommerce-currency-switcher/classes/woocs.php(3642): WC_Abstract_Order->get_currency()
#3 wp-includes/class-wp-hook.php(341): WOOCS->woocommerce_get_order_currency()
#4 wp-includes/plugin.php(205): WP_Hook->apply_filters()
#5 woocommerce/includes/abstracts/abstract-wc-data.php(939): apply_filters()
... repeats until stack/memory exhausted
```

With Xdebug present this aborts cleanly:

```
PHP Fatal error: Uncaught Error: Xdebug has detected a possible infinite loop,
and aborted your script with a stack depth of '512' frames
```

Without Xdebug (production) it instead exhausts memory, and the fatal is reported at whatever allocation happens to fail next — so the reported file/line **varies between runs** (`abstract-wc-deprecated-hooks.php`, `class-wp-hook.php`, `plugin.php`, WPML's `ClassLoader.php`). This makes the bug appear to be caused by unrelated plugins, which cost us several hours of misdiagnosis. Raising `WP_MEMORY_LIMIT` from 512M to 768M did not help — it simply consumed more before dying.

## Steps to reproduce

1. WooCommerce with **HPOS disabled** (legacy post storage)
2. Install FOX 2.5.0
3. Place any order
4. Visit the order-received URL: `/checkout/order-received/{id}/?key={order_key}`
5. → HTTP 500; error log shows infinite recursion / memory exhaustion

Deactivating FOX 2.5.0 makes the same URL return HTTP 200 immediately (verified: 500 → 200, page renders "Thank you. Your order has been received.").

## Suggested fix

Read the currency without re-entering the filter, e.g. read the raw prop / post meta directly, or add a re-entrancy guard:

```php
public function woocommerce_get_order_currency( $order_currency, $order ) {
static $in_progress = false;
if ( $in_progress ) {
return $order_currency;
}
$in_progress = true;
// ... existing logic ...
$in_progress = false;
return $order_currency;
}
```

Given `$order_currency` is already passed into the handler as the first argument, calling `$order->get_currency()` appears unnecessary — using `$order_currency` directly would avoid the recursion entirely.

## Impact for us

Live e-commerce site; every customer completing a booking saw a critical-error page after paying. Mitigated by deactivating FOX, which disables multi-currency display for our customers — we would like to restore it once fixed.

Please confirm whether a 2.5.1 is planned, and in the meantime where we can download **2.4.9** (the version we upgraded from) — the CodeCanyon archive only exposes up to 2.4.2.x.