how to debug Undefined array key 0 in class-wp-query.php

  • JustinBBC

    (@justinbbc)


    5 months ago

    In my error_log in HTML root, I have a bunch of:
    PHP Warning: Undefined array key 0 in /home/mywebsite/public_html/wordpress/wp-includes/class-wp-query.php on line 3733

    Line 3733 is:
    public function next_post() {
    ++$this->current_post;
    /** @var WP_Post */
    $this->post = $this->posts[ $this->current_post ]; <-- line 3733
    return $this->post;
    }

    The times and frequencies appear to be random. I’ve browsed every page and button and link on the site and can’t trigger it.

    How can I debug what is causing this?

Viewing 4 replies - 1 through 4 (of 4 total)
  • Moderator threadi

    (@threadi)

    5 months ago

    Such messages occasionally occur due to faulty handling of plugins or themes with the WordPress core. To investigate this, you could deactivate all plugins and then activate them one by one until the message reappears. Then you will have found the plugin that is causing the problem.

    However, it could also be due to content-related reasons. For example, if a previously used plugin has saved a data record that is still being executed but is no longer compatible with anything. Searching for this is much more time-consuming, which is why I would recommend trying the above first.

    Thread Starter JustinBBC

    (@justinbbc)

    5 months ago

    Well, I can’t deactivate the plugins for an undetermined amount of time since I don’t know when the error will occur (and I assume things won’t function correctly in the interim). However, I did just roll thru them all one-by-one and nothing in the error log.

    How can I find orphaned “data records”? What is a “data record”?

    Moderator threadi

    (@threadi)

    5 months ago

    This refers to the data in the database that contains all the content and settings used by your WordPress website. If you want to go down this route, I would recommend finding someone to help you analyze it. You can find someone here: https://jobs.wordpress.net/

    However, you can also run the tests with the plugins in a copy of the project. Check with your host to see if they offer a staging system or ask them about it. You can also set up a copy on your local computer, for example, to analyze it. This can be done with a migration plugin and localwp, XAMMP, MAMP, or other tools. The effort involved is not insignificant for someone who doesn’t do this often.

    Another alternative would be the plugin https://wordpress.org/plugins/health-check/, which allows you to deactivate all plugins in troubleshooting mode for your own session only. However, this makes it more difficult to check your specific case, as other users are still running the plugins. It depends on how much is going on in your website.

    You can also simply ignore the message. It is only a warning and not an error. You could take this approach especially if you cannot detect any malfunctions in the website anyway.

    Thread Starter JustinBBC

    (@justinbbc)

    5 months ago

    Thanks, threadi, for the tips.

Viewing 4 replies - 1 through 4 (of 4 total)

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