Title: Uncaught Error Last modified: April 10, 2026 --- # Uncaught Error * [dev](https://wordpress.org/support/users/devksec/) * (@devksec) * [2 months ago](https://wordpress.org/support/topic/uncaught-error-56/) * Hi, * We’ve run into what looks like a compatibility issue with your plugin on a WooCommerce site when customers add products to cart via the Store API / Blocks flow. * Error: Uncaught Error: Call to undefined method Automattic\WooCommerce\StoreApi\ SessionHandler::has_session() * File: wp-content/plugins/conditional-extra-fees-for-woocommerce/public/class- apply-payment-processing-fee.php * Line: 28 * Endpoint being hit: [https://store.com/wp-json/wc/store/v1/cart/add-item](https://store.com/wp-json/wc/store/v1/cart/add-item) * From reviewing the stack trace, it appears the plugin is calling WC()->session- >has_session() inside Apply_Payment_Processing_Fee->apply_gateway_fee(). That seems to work with the classic WooCommerce session handler, but during Store API cart requests WooCommerce is using Automattic\WooCommerce\StoreApi\SessionHandler, which does not have that method, so it results in a fatal error. * This means the issue is triggered during add-to-cart/cart recalculation on modern WooCommerce flows rather than only during the traditional checkout flow. * Could you please confirm whether the plugin currently supports WooCommerce Store API / Blocks-based cart and checkout requests, and if not, whether you have a patch planned for this? * It looks like the code may need a guard around has_session() or a different approach so it does not assume the session object always exposes the classic session handler methods. Viewing 11 replies - 1 through 11 (of 11 total) * Plugin Author [jyotsnasingh520](https://wordpress.org/support/users/jyotsnasingh520/) * (@jyotsnasingh520) * [2 months ago](https://wordpress.org/support/topic/uncaught-error-56/#post-18877059) * Hi, * Plugin is compatible with the WooCommerce Block based cart and checkout flow, can you provide the steps to reproduce this issue so we can try it out on our end * Plugin Author [jyotsnasingh520](https://wordpress.org/support/users/jyotsnasingh520/) * (@jyotsnasingh520) * [2 months ago](https://wordpress.org/support/topic/uncaught-error-56/#post-18877070) * Hi, * We cross checked on our end with the API based add to cart /wc/store/v1/cart/ add-item and it is not triggering any error See if you can provide some more detail to reproduce the error and try to run the test in isolation with WooCommerce and conditional fee plugin alone active in the site * Thread Starter [dev](https://wordpress.org/support/users/devksec/) * (@devksec) * [1 month, 3 weeks ago](https://wordpress.org/support/topic/uncaught-error-56/#post-18879871) * Thanks for checking. * I’ve gone back through the stack trace and there are two points that may help narrow this down. * The fatal is not occurring on the classic checkout flow. It is occurring during a Store API cart request on: * `/wp-json/wc/store/v1/cart/add-item` * In our case, the call stack shows WooCommerce recalculating cart totals during that request, which then triggers your fee callback: * `WC_Cart->calculate_fees()` → `Apply_Payment_Processing_Fee->apply_gateway_fee()` * At that point, `WC()->session` is an instance of `Automattic\WooCommerce\StoreApi\ SessionHandler`, not the classic `WC_Session_Handler`. The fatal is specifically: * `Call to undefined method Automattic\WooCommerce\StoreApi\SessionHandler::has_session()` * So the immediate issue is not whether the endpoint exists, but whether the plugin assumes that `WC()->session` always exposes the classic handler methods during Store API / Blocks requests. * For reference, WooCommerce currently has an open core bug describing the same problem in isolation, including the same `has_session()` fatal when a Store API cart request is made and code calls `WC()->session->has_session()`. That report notes that the Store API session handler is not interface-compatible with the default session handler in this scenario. ([GitHub](https://github.com/woocommerce/woocommerce/issues/63053?utm_source=chatgpt.com)) * A few details that may explain why you are not seeing it consistently: 1. It only appears when the plugin’s fee logic actually runs during cart recalculation on a Store API request. 2. A traditional add-to-cart flow may not reproduce it, even if the product page uses modern WooCommerce components elsewhere. 3. Reproduction is more reliable when testing against the real Blocks / Store API cart flow rather than just calling the endpoint in a way that does not reach the same fee path. * A minimal reproduction path on our side is: 1. Activate WooCommerce and Conditional Extra Fees for WooCommerce. 2. Ensure the fee logic is enabled in a way that causes `apply_gateway_fee()` to run during cart totals calculation. 3. Add a product to cart through the Store API / Blocks flow so WooCommerce recalculates fees on `/wc/store/v1/cart/add-item`. 4. The request reaches `apply_gateway_fee()`, where `WC()->session->has_session()` is called on `Automattic\WooCommerce\StoreApi\SessionHandler`, producing the fatal above. * Based on the trace, the safe fix seems to be to avoid assuming `WC()->session` always supports `has_session()` in Store API contexts, for example by adding a guard such as `method_exists( WC()->session, 'has_session' )` before calling it, or by using a Store API-safe approach that does not depend on that classic session handler method being present. * If helpful, I can provide the exact stack trace and environment details from the site where this occurs via email/offline. * Plugin Author [jyotsnasingh520](https://wordpress.org/support/users/jyotsnasingh520/) * (@jyotsnasingh520) * [1 month, 3 weeks ago](https://wordpress.org/support/topic/uncaught-error-56/#post-18879887) * Thanks for the steps we will try to reproduce the issue and let you know * Plugin Author [jyotsnasingh520](https://wordpress.org/support/users/jyotsnasingh520/) * (@jyotsnasingh520) * [1 month, 3 weeks ago](https://wordpress.org/support/topic/uncaught-error-56/#post-18882226) * Hi, * We have release a new version today in that we have added the extra check method_exists( WC()->session, ‘has_session’ ) apart from this in the WooCommerce 10.7 they have implemented has_session inside SessionHandler class Thanks for reporting the issue !! * Thread Starter [dev](https://wordpress.org/support/users/devksec/) * (@devksec) * [1 month, 3 weeks ago](https://wordpress.org/support/topic/uncaught-error-56/#post-18882417) * Great, thank you ! * Thread Starter [dev](https://wordpress.org/support/users/devksec/) * (@devksec) * [1 month, 2 weeks ago](https://wordpress.org/support/topic/uncaught-error-56/#post-18886013) * We’ve now identified a second fatal in the same plugin during WooCommerce Store API cart requests. * This one occurs on: * `GET /wp-json/wc/store/v1/cart?_locale=user` * Fatal: `Call to a member function get_shipping_country() on null` * File: `admin/selection_rules/rules/country.php:115` * From the plugin code, the country rule does: * `$user_country = WC()->customer->get_shipping_country();` * with no null check on `WC()->customer`. * Combined with the earlier fatal on: * `WC()->session->has_session()` * during: * `POST /wp-json/wc/store/v1/cart/add-item` * this suggests the plugin is assuming classic WooCommerce customer/session objects are always present during Store API requests. * WooCommerce’s Cart and Checkout blocks use the Store API for normal frontend cart activity, so these requests are part of expected customer browsing, not necessarily bot traffic. The issue appears to be that the plugin is not handling Store API contexts defensively. * At this point we have two separate Store API fatals in the plugin: 1. `StoreApi\SessionHandler::has_session()` 2. `WC()->customer` being null in the country rule * That looks like a broader Store API compatibility issue rather than an isolated edge case. * Plugin Author [jyotsnasingh520](https://wordpress.org/support/users/jyotsnasingh520/) * (@jyotsnasingh520) * [1 month, 2 weeks ago](https://wordpress.org/support/topic/uncaught-error-56/#post-18886278) * Thanks for the info, can you please also provide the steps to reproduce this issue, that will be really helpful. * Thread Starter [dev](https://wordpress.org/support/users/devksec/) * (@devksec) * [1 month, 2 weeks ago](https://wordpress.org/support/topic/uncaught-error-56/#post-18886468) * Thanks. To be clear, this was observed on a live production site rather than an isolated test install, so I cannot yet give you a guaranteed single-click sandbox repro. * What I can give you is the exact plugin version, the failing code paths, the request endpoints, and the configuration conditions that make the issue reachable. * Plugin version: `conditional-extra-fees-for-woocommerce 1.1.49.42` * We have now seen two separate fatals in your plugin during WooCommerce Store API cart requests. 1. Payment processing fee path * File: `public/class-apply-payment-processing-fee.php:28` * Code: * ```wp-block-code if (isset(WC()->session) && WC()->session->has_session()) { ``` * Failing request: `POST /wp-json/wc/store/v1/cart/add-item` * Fatal: `Call to undefined method Automattic\WooCommerce\StoreApi\SessionHandler:: has_session()` * This path becomes reachable when: - WooCommerce is recalculating cart fees during a Store API cart request, and - the payment processing fee feature is enabled so `apply_gateway_fee()` runs. * 2. Country rule path * File: `admin/selection_rules/rules/country.php:115` * Code: * ```wp-block-code $user_country = WC()->customer->get_shipping_country(); ``` * Failing request: `GET /wp-json/wc/store/v1/cart?_locale=user` * Fatal: `Call to a member function get_shipping_country() on null` * This path becomes reachable when: - cart fees are calculated during a Store API cart/cart refresh request, and - at least one fee rule uses the `Country/Continent` condition so `Pi_cefw_selection_rule_country- >conditionCheck()` runs. * So while I cannot yet provide a clean sandbox repro from our side, the expected reproduction setup on your side should be: * For the first issue: 1. Fresh WooCommerce install. 2. Activate only WooCommerce + Conditional Extra Fees for WooCommerce. 3. Enable a payment processing fee rule so `Apply_Payment_Processing_Fee->apply_gateway_fee()` is active. 4. Trigger Store API cart add-to-cart flow via `/wp-json/wc/store/v1/cart/add-item`. 5. Observe whether `WC()->session` is a Store API session handler on that request and whether `has_session()` is called. * For the second issue: 1. Fresh WooCommerce install. 2. Activate only WooCommerce + Conditional Extra Fees for WooCommerce. 3. Create any fee rule using the `Country/Continent` condition. 4. Open the cart or trigger `/wp-json/wc/store/v1/cart?_locale=user`. 5. Observe whether `WC()->customer` is null when `conditionCheck()` runs. * Even if you cannot reproduce immediately, both code paths currently assume classic WooCommerce objects are always available in Store API requests: - `WC()->session->has_session()` - `WC()->customer->get_shipping_country()` * Those assumptions are what our production traces are failing on. * If helpful, I can also send the full stack traces for both errors. * Plugin Author [jyotsnasingh520](https://wordpress.org/support/users/jyotsnasingh520/) * (@jyotsnasingh520) * [1 month, 2 weeks ago](https://wordpress.org/support/topic/uncaught-error-56/#post-18886563) * First issue reported by you is already fixed in the new version that was release 4 days back that is in **1.1.49.43** * apart from this WooCommerce 10.7 has included has_session() function in the SessionHandler class itself * We will try to reproduce the 2nd issue we have not being able to reproduce it with your given steps we will try some other setup * Plugin Author [jyotsnasingh520](https://wordpress.org/support/users/jyotsnasingh520/) * (@jyotsnasingh520) * [1 month, 2 weeks ago](https://wordpress.org/support/topic/uncaught-error-56/#post-18889985) * Hi, * We have released a new version v1.1.49.44 today in this we have added some more check for the customer access WC()->customer Viewing 11 replies - 1 through 11 (of 11 total) You must be [logged in](https://login.wordpress.org/?redirect_to=https%3A%2F%2Fwordpress.org%2Fsupport%2Ftopic%2Funcaught-error-56%2F%3Foutput_format%3Dmd&locale=en_US) to reply to this topic. * ![](https://ps.w.org/conditional-extra-fees-for-woocommerce/assets/icon.svg?rev =2538481) * [PiWeb Conditional cart fee / Extra charge rule for WooCommerce](https://wordpress.org/plugins/conditional-extra-fees-for-woocommerce/) * [Frequently Asked Questions](https://wordpress.org/plugins/conditional-extra-fees-for-woocommerce/#faq) * [Support Threads](https://wordpress.org/support/plugin/conditional-extra-fees-for-woocommerce/) * [Active Topics](https://wordpress.org/support/plugin/conditional-extra-fees-for-woocommerce/active/) * [Unresolved Topics](https://wordpress.org/support/plugin/conditional-extra-fees-for-woocommerce/unresolved/) * [Reviews](https://wordpress.org/support/plugin/conditional-extra-fees-for-woocommerce/reviews/) * 14 replies * 2 participants * Last reply from: [jyotsnasingh520](https://wordpress.org/support/users/jyotsnasingh520/) * Last activity: [1 month, 2 weeks ago](https://wordpress.org/support/topic/uncaught-error-56/#post-18889985) * Status: not resolved