One-Page Checkout [Support Thread]

[bumba000]

Hello All.
A fresh install of ZC 2.2.2 on upgraded DB from 1.5.5e, running on PHP 8.3. Just installed the OPC. I've got a few issues.



Add an item to the cart > click checkout. I get options to sign in, checkout as guest or create account. If I select guest checkout, navigate away from the process then click checkout again, I'm taken straight into the guest checkout. But, what if I changed my mind and want to either log into my existing account or want to create a full account? I have to open a new private window to begin a new session. Is there a way around this?

At the top of the guest checkout page I see "WARNING: Could not locate language file: includes/languages/english/modules/order_total/ot_sc.php". It doesn't appear this file is included with ZC 2.2.2 or with OPC. Please advise. (we used to offer rewards and store credit so I may just need to remove some db stuff)

At the bottom of the guest checkout I see a box that says "Bottom Instructions". What is this used for?

Thank you,
John

[bumba000]

Hello All.
A fresh install of ZC 2.2.2 on upgraded DB from 1.5.5e, running on PHP 8.3. Just installed the OPC. I've got a few issues....

So I resolved a the missing file warning by replacing configuration and configuration group db tables with those from an actual fresh install. Then in the admin I uninstalled and re-installed OPC. The configuration table was actually quite a mess since the database is essentially the original since 2007. So, that's all cleaned up now. lol

As for the "Bottom Instructions" thing. I could find nothing on this in admin > config > OPC, or in the release documentation. So looking in dev tools I found the define. Then so on from there. Setting the define to blank the box goes away.

Thank you,
John

[lat9]

So I resolved a the missing file warning by replacing configuration and configuration group db tables with those from an actual fresh install. Then in the admin I uninstalled and re-installed OPC. The configuration table was actually quite a mess since the database is essentially the original since 2007. So, that's all cleaned up now. lol

As for the "Bottom Instructions" thing. I could find nothing on this in admin > config > OPC, or in the release documentation. So looking in dev tools I found the define. Then so on from there. Setting the define to blank the box goes away.

Thank you,
John

Glad you got most of it worked out. I'll note that OPC's readme does point you to its Wiki articles; here's the one that describes those "Bottom instructions": https://github.com/lat9/one_page_che...mation-message

[njcyx]

opc 2.5.2

I just noticed an issue.

So if you first time enter the checkout page, after you enter the address under "Billing/Shipping Address:" section, click "Submit", then uncheck the box "Shipping Address, Same as Billing?". Then the top section is billing and bottom section is shipping.

Then click the edit button in billing address, then click on "Cancel". The top box name is changed from billing to "Billing/Shipping Address:". So at this moment, the top address box is "Billing/Shipping Address:" and bottom is "Shipping Address:", which is incorrect.

If you change anything in the top section then click confirm, not cancel, the name for top section will be correct, which is "Billing address".

I assumed it could be related to the JS.

My production site is running OPC 2.5.5 and it has the same issue.

[lat9]

opc 2.5.2

I just noticed an issue.

So if you first time enter the checkout page, after you enter the address under "Billing/Shipping Address:" section, click "Submit", then uncheck the box "Shipping Address, Same as Billing?". Then the top section is billing and bottom section is shipping.

Then click the edit button in billing address, then click on "Cancel". The top box name is changed from billing to "Billing/Shipping Address:". So at this moment, the top address box is "Billing/Shipping Address:" and bottom is "Shipping Address:", which is incorrect.

If you change anything in the top section then click confirm, not cancel, the name for top section will be correct, which is "Billing address".

I assumed it could be related to the JS.

My production site is running OPC 2.5.5 and it has the same issue.

Thanks for the report. I've reproduced the issue on v2.6.2 and created this GitHub issue for tracking: https://github.com/lat9/one_page_checkout/issues/470

[njcyx]

Thanks. It looks like it is a long term issue which affect from OPC 2.5.5 to 2.6.2.

Anyway, sometimes, our customer complained that the billing and shipping addresses are reversed somehow in their orders. I tried several times in the past but I cannot reproduce the issue. Not sure if this issue cause it, since the customer may get confused which section is the true shipping address.

[lat9]

Thanks. It looks like it is a long term issue which affect from OPC 2.5.5 to 2.6.2.

Anyway, sometimes, our customer complained that the billing and shipping addresses are reversed somehow in their orders. I tried several times in the past but I cannot reproduce the issue. Not sure if this issue cause it, since the customer may get confused which section is the true shipping address.

I'll take a look at that when I correct the billing-address labeling, but I'm not sure how that can happen since the bill-to and ship-to addresses are quire separate in OPC's handling.

[njcyx]

opc v2.6.1, zc2.1.0, paypalwpp, php 8.1

I received the following intermittent warning.

[11-May-2026 15:08:12 America/New_York] PHP Fatal error: Uncaught Error: Typed property OnePageCheckout::$isVirtualOrder must not be accessed before initialization in /includes/classes/OnePageCheckout.php:2568
Stack trace:
#0 /includes/classes/observers/class.checkout_one_observer.php(685): OnePageCheckout->getTaxLocations()
#1 /includes/classes/traits/NotifierManager.php(106): checkout_one_observer->update(Object(notifier), 'ZEN_GET_TAX_LOC...', Array, false, NULL, NULL, NULL, NULL, NULL, NULL, NULL)
#2 /includes/functions/functions_taxes.php(355): base->notify('ZEN_GET_TAX_LOC...', Array, false)
#3 /includes/modules/order_total/ot_tax.php(66): zen_get_tax_locations()
#4 /includes/classes/order_total.php(229): ot_tax->process()
#5 /includes/modules/payment/paypalwpp.php(1637): order_total->pre_confirmation_check()
#6 /ipn_main_handler.php(81): paypalwpp->ec_step1()
#7 {main}
thrown in /includes/classes/OnePageCheckout.php on line 2568

[11-May-2026 15:08:12 America/New_York] Request URI: /ipn_main_handler.php?type=ec, IP address: xxx
--> PHP Fatal error: Uncaught Error: Typed property OnePageCheckout::$isVirtualOrder must not be accessed before initialization in /includes/classes/OnePageCheckout.php:2568
Stack trace:
#0 /includes/classes/observers/class.checkout_one_observer.php(685): OnePageCheckout->getTaxLocations()
#1 /includes/classes/traits/NotifierManager.php(106): checkout_one_observer->update(Object(notifier), 'ZEN_GET_TAX_LOC...', Array, false, NULL, NULL, NULL, NULL, NULL, NULL, NULL)
#2 /includes/functions/functions_taxes.php(355): base->notify('ZEN_GET_TAX_LOC...', Array, false)
#3 /includes/modules/order_total/ot_tax.php(66): zen_get_tax_locations()
#4 /includes/classes/order_total.php(229): ot_tax->process()
#5 /includes/modules/payment/paypalwpp.php(1637): order_total->pre_confirmation_check()
#6 /ipn_main_handler.php(81): paypalwpp->ec_step1()
#7 {main}
thrown in /includes/classes/OnePageCheckout.php on line 2568. 

Line 2568 is the following

"if ($this->isVirtualOrder === true || $this->getShippingBilling() === true) {"

The customer under this IP address has placed the order successfully (no sales tax was charged, which is also correct.) and he didn't order the virtual item.

I just updated my site to opc 2.6.2 from 2.5.5 and this issue remains.

[njcyx]

I checked the file includes/classes/observers/class.checkout_one_observer.php and line 31 is indeed.

if (empty($_SESSION['opc']) || !is_object($_SESSION['opc']) || ($_GET['type'] ?? '') === 'ec') {

So this fix may not work.

[lat9]

I checked the file includes/classes/observers/class.checkout_one_observer.php and line 31 is indeed.

if (empty($_SESSION['opc']) || !is_object($_SESSION['opc']) || ($_GET['type'] ?? '') === 'ec') {

So this fix may not work.

I'm having a really, really, hard time determining why this error persists in the presence of the above conditional. The log indicates that the request is coming from Request URI: /ipn_main_handler.php?type=ec, IP address: xxx , so $_GET['type'] is === 'ec' so the observer should simply return without 'attaching' to that ZEN_GET_TAX_LOCATIONS notification.