In a recent Business Bloomer Club Slack thread, an important discussion emerged about significant changes to WooCommerce’s cart management system. The conversation highlighted how cart merging currently works and the controversial decision to modify this behavior.
This change affects how customers’ shopping carts are handled when they switch between guest browsing and logged-in sessions, potentially impacting user experience and conversion rates for online stores. Understanding these changes is crucial for store owners who want to maintain smooth checkout processes and avoid customer frustration.
The modifications touch on fundamental ecommerce functionality that many users have come to expect from their shopping experience. Store owners should be aware of these changes to prepare for potential customer behavior shifts and consider whether the new approach aligns with their business goals.
How WooCommerce Cart Merging Used to Work
The cart merging system in WooCommerce follows a logical pattern that many customers have grown accustomed to over the years. When a customer visits your store and logs into their account, the system recognizes they may have items from previous sessions that should be preserved alongside their current shopping activity.
Here’s the typical scenario that plays out thousands of times daily across WooCommerce stores worldwide. A customer logs into your store during their last visit and adds Product A to their cart. Maybe they got distracted, had to leave for work, or simply decided to think about the purchase overnight. Later, they return to your site but this time browse as a guest without logging in immediately. During this guest session, they discover Product B and add it to their cart.
The moment they decide to log in, WooCommerce’s cart merging functionality kicks in automatically. The system recognizes both the previous logged-in cart containing Product A and the current guest cart with Product B. Instead of losing either item, it intelligently combines both carts, presenting the customer with both Product A and Product B ready for checkout.
This behavior makes intuitive sense from a customer perspective. They expect their previous shopping intentions to be remembered and preserved, while also maintaining their current browsing session’s selections. The merge prevents the frustrating experience of losing items they had previously considered purchasing.
The Controversial Change
However, this established behavior was set to change, and the modification sparked considerable debate within the development community. The proposed change would eliminate cart merging entirely, fundamentally altering how customers experience the transition from guest to logged-in shopping.
Under the new system, when a customer logs in after adding items as a guest, only their current guest cart would be preserved. In our previous example, this means Product A from their previous logged-in session would be completely discarded, leaving only Product B in their cart after login.
The technical reasoning behind this change centers on simplifying WooCommerce’s cart persistence architecture. Currently, the system maintains both session-based carts and persistent carts stored in user metadata, requiring complex synchronization between these two storage methods. The development team argues that removing this dual-system approach will improve performance and reduce potential conflicts.
Why This Change Matters for Your Store
The implications of this modification extend far beyond technical architecture improvements. Customer behavior patterns have been shaped by years of cart merging functionality, and disrupting these expectations could have unintended consequences for your store’s conversion rates.
Many customers rely on cart merging as an informal wishlist system. They might add items during one session, leave to research or compare prices, then return later and add additional items before completing their purchase. The current system supports this natural shopping behavior by preserving all their previous selections.
Removing cart merging could lead to customer frustration when they discover that items they previously added have disappeared upon login. This scenario becomes particularly problematic for higher-value items or products that required significant research time to select initially.
The change also affects mobile shopping patterns, where customers frequently switch between apps, browsers, and devices. Cart merging helps bridge these transitions, ensuring that items added across different browsing sessions remain accessible when customers are ready to purchase.
Community Response and Developer Concerns
The GitHub discussion surrounding this change reveals significant pushback from both developers and business owners who understand the importance of cart merging for user experience. Many community members have expressed concerns that removing this functionality could harm conversion rates and create unnecessary friction in the checkout process.
Several developers have noted that cart merging serves as more than just a convenience feature — it’s an expectation that customers have developed based on standard ecommerce behavior across multiple platforms. Disrupting this expectation without providing alternative solutions could drive customers away at the crucial moment when they’re ready to complete a purchase.
The debate also highlights the tension between technical optimization and user experience preservation. While simplifying the underlying architecture may provide performance benefits, these improvements become meaningless if they result in decreased sales or customer satisfaction.
Pull Request Recap
The PR removes WooCommerce’s persistent cart functionality that was stored in user metadata and replaces it with a session-based approach using longer duration sessions.
Main Technical Changes:
- Removed persistent cart storage from user metadata (
usermetatable) - Extended session duration to 1 week for logged-in users (instead of relying on separate persistent cart storage)
- Simplified cart logic by removing the need to sync data between sessions and persistent carts
- Added new filter
woocommerce_migrate_guest_session_to_user_sessionto control data migration when guests log in
Initial Approach
- Removed cart merging completely – if a guest had a cart and logged in, the previous logged-in cart would be discarded
- The rationale was to avoid unexpected changes, especially during checkout
Community Feedback
Multiple developers and users expressed concerns about removing cart merging:
- @BusinessBloomer: “I honestly don’t see why you should remove the ‘merge cart’ thing. It’s a good ecommerce feature.”
- @codeagencybe: “I don’t agree that the merge function must be deleted. I prefer the behavior as it is today.”
- @rwkyyy: “I know a lot of people who do this (myself included), add things to cart then log in.”
Final Approach (June 2025):
Cart merging was restored after the community feedback. The PR author noted:
“I’ve updated the approach to merge after confirming login is never automatic on checkout, so you at least see order summary with the merged contents. Can be revisited if needed. For now this mimics status quo.”
Benefits
- Performance improvement – fewer database writes due to removing persistent cart syncing
- Simplified logic – no more complex synchronization between sessions and user metadata
- Bug fixes – addresses issues #26374 and #40669 related to cart inconsistencies
The PR successfully maintained the existing user experience for cart merging while improving the underlying architecture by moving from a dual-storage system (sessions + usermeta) to a single session-based approach with extended duration.
Conclusion
The proposed changes to WooCommerce’s cart merging functionality represent a significant shift in how the platform handles customer shopping sessions. While the technical benefits may improve backend performance, the user experience implications deserve careful consideration.
Store owners should stay informed about these developments and prepare to adapt their customer experience strategies accordingly. The outcome of this debate will likely shape how millions of online shoppers interact with WooCommerce stores in the future.
