WooCommerce get_cart Error

### Cause
The error occurs because a function (like `get_cart`) or WooCommerce-related functionality is being invoked too early, often during the `init` action or even earlier. This can happen due to:
1. Custom code in a theme or plugin calling WooCommerce functions prematurely.
2. A plugin improperly using WooCommerce hooks.
3. Misconfigured code in your child theme.

### Solution
#### 1. **Identify the Source**
The error traceback points to `Automattic\WooCommerce\Blocks\BlockTypesController->register_blocks`. This suggests WooCommerce Blocks may be registering incorrectly or there's a conflict with custom code/hooks.

– Check for custom hooks or functions in your theme’s `functions.php` or plugin code that interact with WooCommerce.
– Look for anything calling `WC()->cart` or similar cart functions.

#### 2. **Fix the Timing**
Ensure WooCommerce functions are only called after `wp_loaded`. For example, wrap problematic code like this:

add_action('wp_loaded', function() {
    // Safe place to use WooCommerce functions like WC()->cart
    if (function_exists('WC') && WC()->cart) {
        $cart = WC()->cart->get_cart();
        // Your logic here
    }
});

#### 3. **Disable and Re-enable Plugins**
To isolate the issue:
1. Disable all plugins except WooCommerce.
2. Check if the error persists.
3. Re-enable plugins one by one to identify the conflicting plugin.

#### 4. **Review Custom Code**
If you have custom blocks, ensure they do not use WooCommerce functions before `wp_loaded`. Check for any direct usage of `WC()->cart` or similar in your theme or plugins.

#### 5. **Update WooCommerce**
Ensure you're using the latest version of WooCommerce and WooCommerce Blocks. Older versions might contain bugs leading to this issue.

#### 6. **Debugging**
Enable WP Debugging by adding the following lines to your `wp-config.php`:

define('WP_DEBUG', true);
define('WP_DEBUG_LOG', true);

Check the `wp-content/debug.log` file for more detailed information.

Let me know if you'd like assistance pinpointing the root cause!

if (WC()->cart && !WC()->cart->is_empty()) {
foreach (WC()->cart->get_cart() as $cart_item) {
$product_id = $cart_item['product_id'];
$disable_paypal = get_post_meta($product_id, '_disable_paypal', true);

if ($disable_paypal === 'yes') {
unset($available_gateways['ppcp-gateway']);
break;
}
}
}
return $available_gateways;
}

### Fixing the Timing
You can avoid calling `WC()->cart` too early by ensuring that the code runs only when the cart is fully loaded, i.e., after the `wp_loaded` action. The correct approach would be to hook into `wp_loaded` or another appropriate hook to ensure the cart is available when this function runs.

Here’s how you can modify your code to ensure it's triggered at the right time:

### Modified Code:

function pmmv1_disable_paypal_for_specific_products($available_gateways) {
    // Ensure WC()->cart is available after wp_loaded action
    if (is_admin() || !WC()->cart) {
        return $available_gateways;
    }

    if (!WC()->cart->is_empty()) {
        foreach (WC()->cart->get_cart() as $cart_item) {
            $product_id = $cart_item['product_id'];
            $disable_paypal = get_post_meta($product_id, '_disable_paypal', true);

            if ($disable_paypal === 'yes') {
                unset($available_gateways['ppcp-gateway']);
                break;
            }
        }
    }
    return $available_gateways;
}

// Hook into the payment gateways filter
add_filter('woocommerce_available_payment_gateways', 'pmmv1_disable_paypal_for_specific_products');

### Key Changes:
1. **Check if WooCommerce is Ready:**
The condition `if (is_admin() || !WC()->cart)` ensures that the cart is not being accessed prematurely (i.e., before it’s fully loaded). This check ensures the code doesn't run on pages where WooCommerce isn't fully initialized.

2. **Hook into `woocommerce_available_payment_gateways`:**
This hook ensures your code runs at the right time when the payment gateways are being determined.

### Additional Notes:
– Ensure that you are using the correct gateway ID (`'ppcp-gateway'` in your case).
– Double-check the `get_post_meta($product_id, '_disable_paypal', true)` value to ensure it’s being correctly set to `'yes'` on products that should have PayPal disabled.

This should resolve the issue where WooCommerce functions are being called too early in the lifecycle. Let me know if this works for you!

Here’s how you can ensure it works correctly:

### Corrected Function with Proper Hook

function pmm_empty_cart_mobile_fragment($fragments)
{
    // Ensure WC()->cart is available and initialized
    if (WC()->cart && WC()->cart->get_cart_contents_count() === 0) {
        $fragments['.wc-proceed-to-checkout-mobile'] = '<a href="/checkout/" style="display:none;" class="checkout-button button alt wc-forward">Proceed to checkout <span class="woocommerce-Price-amount amount"></span></a>';
    }
    return $fragments;
}

// Hook into WooCommerce fragments
add_filter('woocommerce_add_to_cart_fragments', 'pmm_empty_cart_mobile_fragment');

### Key Changes:
1. **Ensure WC()->cart is Initialized:**
The condition `if (WC()->cart && WC()->cart->get_cart_contents_count() === 0)` ensures that the cart is properly initialized before attempting to access it.

2. **Use the Correct Hook:**
The `woocommerce_add_to_cart_fragments` filter is specifically designed for updating fragments on the frontend, which is the right hook for this functionality.

3. **Maintain Compatibility with Frontend Rendering:**
Fragments are a WooCommerce feature for updating parts of the page dynamically without a full refresh (e.g., when items are added or removed from the cart). Using the right hook ensures your updates integrate seamlessly.

### Additional Suggestions:
– **CSS Selector Validation:** Ensure `.wc-proceed-to-checkout-mobile` exists in your theme or plugin’s DOM structure. Otherwise, the fragment update won’t have any visible effect.
– **Optimize for Performance:** If this functionality is tied to the mobile view, consider adding a condition to check if the user is on a mobile device (though this is optional).

Let me know if you encounter further issues or need additional refinements!

### Analysis
1. **Functionality Check:**
– The `is_cart()` function ensures that this block only runs on the cart page.
– The `WC()->cart->get_cart_contents_count()` ensures the button is only displayed if there are items in the cart.

2. **Dynamic Total Display:**
– The total is fetched using `WC()->cart->get_total()`, and `wp_kses_data()` is used to sanitize the output.

3. **Output Validation:**
– Ensure that the CSS class `.wc-proceed-to-checkout-mobile` exists in your stylesheets for this button to be styled and positioned correctly.

### Suggested Improvements

#### 1. **Add `esc_url` to the Checkout Link**
It's best practice to sanitize URLs using `esc_url()` to avoid potential security issues.

#### 2. **Enhance Code Readability**
Simplify your logic and ensure variables are well-named for better maintainability.

#### 3. **Localization Support**
Make the text "Proceed to checkout" translatable using `__()` or `_e()` functions.

### Updated Code

<?php if (is_cart() && WC()->cart->get_cart_contents_count() > 0): ?>
    <div class="wc-proceed-to-checkout wc-proceed-to-checkout-mobile">
        <a href="<?php echo esc_url(wc_get_checkout_url()); ?>" class="checkout-button button alt wc-forward">
            <?php _e('Proceed to checkout', 'your-text-domain'); ?>
            <span class="woocommerce-Price-amount amount">
                <?php echo wp_kses_data(WC()->cart->get_total()); ?>
            </span>
        </a>
    </div>
<?php endif; ?>

### Key Changes
1. **Sanitized the Checkout URL:**
– Used `wc_get_checkout_url()` instead of a hardcoded `/checkout/` URL for flexibility.

2. **Text Localization:**
– Wrapped the text "Proceed to checkout" in `__('string', 'text-domain')` to make it translatable.

3. **CSS and HTML Compatibility:**
– No changes to the structure; ensure your theme styles the `.wc-proceed-to-checkout-mobile` class appropriately.

### Additional Suggestions
– **Responsive Styling:**
Make sure the `.wc-proceed-to-checkout-mobile` class is styled specifically for mobile devices using CSS media queries.

– **Handle Empty Carts:**
If users empty their carts on the cart page, ensure the button disappears dynamically. This could be done with WooCommerce cart fragments.

Let me know if you need help implementing these changes!