Check if cart exists before calling a method

[Narek13]

Issue: #603

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Description

There are multiple errors reported:

2022-04-07T09:18:27+00:00 CRITICAL Uncaught Error: Call to a member function get_cart_contents_total() on null in /chroot/home/a4084adf/wealthyhair.com/html/wp-content/plugins/woocommerce-paypal-payments/modules/ppcp-button/src/Assets/SmartButton.php:1127
Stack trace:
#0 /chroot/home/a4084adf/wealthyhair.com/html/wp-content/plugins/woocommerce-paypal-payments/modules/ppcp-button/src/Assets/SmartButton.php(378): WooCommerce\PayPalCommerce\Button\Assets\SmartButton->is_cart_price_total_zero()
#1 /chroot/home/a4084adf/wealthyhair.com/html/wp-content/plugins/woocommerce-paypal-payments/modules/ppcp-button/src/Assets/SmartButton.php(195): WooCommerce\PayPalCommerce\Button\Assets\SmartButton->render_button_wrapper_registrar()
#2 /chroot/home/a4084adf/wealthyhair.com/html/wp-content/plugins/woocommerce-paypal-payments/modules/ppcp-button/src/ButtonModule.php(56): WooCommerce\PayPalCommerce\Button\Assets\SmartButton->render_wrapper()
#3 /chroot/home/a4084adf/wealthyhair.com/html/wp-includes/class-wp-hook.php(307): WooCommerce\PayPalCommerce\Button\But in /chroot/home/a4084adf/wealthyhair.com/html/wp-content/plugins/woocommerce-paypal-payments/modules/ppcp-button/src/Assets/SmartButton.php on line 1127

The PR will fix the error by adding a check if WC()->cart exists.

Steps to Test

not quite sure how to reproduce but there are multiple reports.

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Closes #603 .

[braddalton]

Any idea when this fix will be committed? I can't use WooCommerce Payments because i'm in a excluded country. There are others reporting this issue with PP CC payments on front end losing sales.

2022-05-15T17:44:18+00:00 CRITICAL Uncaught Error: Call to a member function get_cart_contents_total() on null in /nas/content/live/wpsites/wp-content/plugins/woocommerce-paypal-payments/modules/ppcp-button/src/Assets/SmartButton.php:1227
Stack trace:
#0 /nas/content/live/wpsites/wp-content/plugins/woocommerce-paypal-payments/modules/ppcp-button/src/Assets/SmartButton.php(448): WooCommerce\PayPalCommerce\Button\Assets\SmartButton->is_cart_price_total_zero()
#1 /nas/content/live/wpsites/wp-content/plugins/woocommerce-paypal-payments/modules/ppcp-button/src/Assets/SmartButton.php(229): WooCommerce\PayPalCommerce\Button\Assets\SmartButton->render_button_wrapper_registrar()
#2 /nas/content/live/wpsites/wp-content/plugins/woocommerce-paypal-payments/modules/ppcp-button/src/ButtonModule.php(57): WooCommerce\PayPalCommerce\Button\Assets\SmartButton->render_wrapper()
#3 /nas/content/live/wpsites/wp-includes/class-wp-hook.php(307): WooCommerce\PayPalCommerce\Button\ButtonModule::WooCommerce\PayPalCommerce\Button{closure}(Object(WP))
#4 /nas/content/li in /nas/content/live/wpsites/wp-content/plugins/woocommerce-paypal-payments/modules/ppcp-button/src/Assets/SmartButton.php on line 1227

[InpsydeNiklas]

resolved in #606