[Resolved] Undefined index: GBP.JSON + Trying to access array offset on value of type null

Hi there

Sorry for the delay in someone getting to this ticket, I will handle it from now.

I have access to your production site, but I can't test on that, as at a minimum I'll need to deactivate most of the plugins on your site and switch theme and disable caching to try and isolate the cause of the problem.

Do you have a staging server I could use for testing? If not can I make a copy of the site on another server?

Do you have any information about the steps that trigger the issue? (I'm guessing that you are simply seeing the notices in your debug logs and don't know what prompts them, but if you know that it involves some workflow, please let me know.)

OK, I've set up a private reply for you to share details of the staging server.

Although your site is functioning okay, it is generating these notices in the logs, and to be able to try and isolate the cause I will need to do things like disable plugins and switch theme, as well as possibly installing some debugging tools.

Thank you for those. The file.io link has been deleted so I can't see your production log.

On the staging server the debug.log contains lots of notices from other plugins—font and caching plugins—but not the issue that you reported.

I have been navigating the site, adding products to the cart, switching language, switching currency, but haven't been able to do anything that triggers the PHP notices you shared above.

(The one thing I didn't do was complete the checkout process and pay for goods.)

We need to be able to identify some steps that trigger the notices to be able to understand the cause.

Might I suggest that on your production server you add an activity monitor plugin to record all of the actions that are taken on your site. Then it may be possible to compare the exact time the PHP notices are generated with details of what actions were being taken on the site at the same time from the activity log, to give an indication of the steps we can use to try to reproduce the issue.

If you could please try that and let me know what you find.

The activity logging would be a temporary measure to help identify what action triggers the notices.

I need some steps to be able to trace what happens that results in the notice to identify the cause.

Your original post shows the PHP notices, but without a stack trace, so there is currently no clue as to why the notices are being triggered.

I've located the production server and checked the debug.log with FTP.

It only has entries covering a few hours this morning, but all of the notices are other notices from other plugins and your theme, not the notices you reported above.

I'll return to it later to see if it updates with those same notices.

I had already checked our internal tickets and the forum for any other cases reporting the same PHP notice, but found nothing.

If you have seen a forum thread with the same issue, please share the links with me so I can check them, they may have useful details.

For now, I have no information about the steps to reproduce the notices, nor details of the PHP stack when the notices are triggered, only the notices themselves.

It is clear what the proximate cause of the notice is—the function apply_rounding_rules is being passed the variable $currency, which should be a currency code but is instead a currency JSON object—but without the stack trace or reproduction steps to be able to monitor the code execution we can't say why $currency is being passed wrongly.

One thing we can try is I can edit the plugin file where the notice is generated and manually create a stack trace to output to the debug.log, so that there will be details of how the function was called.

It would be a minor edit that I would leave in place only until the notices re-appear in the debug.log, which should give some clues as to what triggered them.

Would that be okay?