Problems with a plugin I am developing, and the 'Are you sure you want to do this?' message.

Not my first plugin, and it is following the general guidelines for development. The plugins' function is to perform a database query on a button press on the plugin settings screen. That all functions properly.

The function for the button press (in a form) displays the form/button on the Settings page. The form's action is to itself, so the plugin settings page is displayed on the button press/form submit (after performing the desired function for the button/submit).

I have noticed the following

  • The plugin cannot be deactivated on the plugin screen - the screen is redrawn, but no deactivation message and the plugin is still active. Plugin deactivation code is standard and per Codex; nothing fancy,
    just deactivate.
  • The 'Are you sure..' error message is displayed on a post
    save/publish attempt. Post is not saved.
  • This error message is in the wp-admin error log:

"PHP Warning: array_merge(): Argument #2 is not an array in /[specific file location redacted]/wp-includes/load.php on line 664'

  • There is no nonce checking in the form on the settings page (used to be, but removed that during testing to no avail) (And yes, I know the risk; it's not there while I debug things, and Post values from the form are already sanitized elsewhere.)

  • There is no check_admin_referer() code in my plugin

  • I have verified the plugin causing the error by removing the plugin folder

  • It is not a permissions error.
  • It is not a memory error (the plugin increases the memory_limit to 256M)

  • Have asked the googles; nothing helpful there.

What should I be looking for in my plugin code (too long to reproduce here)? Where should the form for the button be displayed optimially (or is that even related to the error)?

1 Answer 1


It appears that the issue is related to my uses of this code:

$_GET = filter_input_array(INPUT_GET, FILTER_SANITIZE_STRING) ;

I had placed this at the top of the plugin (outside of the plugin's class); I used it to sanitize any GET and POST values.

When you do any action (like a Post or Page Publish, or a plugin deactivate) that results in a $_POST, the wp_magic_quotes() function in load.php gets called (via the check_admin_referer() function, called on all $_POSTs on all pages, including a Publish and a plugin deactivate POST):

// code fragment from wp_magic_quote() in load.php
// Force REQUEST to be GET + POST.
$_REQUEST = array_merge( $_GET, $_POST );

My filter_input_array code (which I use to sanitize $_GETs and $_POSTs) was causing the second parameter in the array_merge() to not be an array, which caused this error to show up in the wp-admin folder error log:

    "PHP Warning: array_merge(): Argument #2 is not an array 
in /[specific file location redacted]/wp-includes/load.php 
on line 664'

By moving the filter_input_array statements (first code block above) inside the check for the Submit button on the plugin settings form, the error went away. Apparently, my filter_input_array statements conflicted with the wp_magic_quotes use of the $_POST parameters.

Moving my filter_input_array statements inside the 'check for the plugin settings page button submit' appears to have fixed the problem.

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