preg_match() with custom permalinks caused by Events Manager

Which version of Events Manager and WordPress are you using?

The most recent versions: WordPress is at 4.5.3–fr_FR and Events manager at 5.6.5.

What do you have set under Events > Settings > Pages > Permalink Slugs?

I did not touch these settings at all.

So they are set to the default:

events
locations
events/categories
events/tags

I did play around with parameters in Events > Settings > Pages > Event Pages and set the ‘Display events as’ to ‘Pages’ and the problem went away. Then I set it back to ‘Posts’ and it did not came back.

Maybe changing this set some setting where a default was missing after the installation ?

just to narrow down the problem and help us debug the issue is it possible to try the following temporarily:

– deactivating all other plugins to see if this resolves the problem. If this works, re-activate the plugins one by one until you find the problematic plugin(s).
– switching to the default theme to rule out any theme-specific problems

I’ve taken the following actions:

1) Verified that the site is running. My test page is ‘access’ a page with some information.
-> All is well
2) Enable the extension ‘Events Manager’
-> I get 7 message pairs like this on most pages:
Warning: preg_match(): Compilation failed: nothing to repeat at offset 1 in /home/clients/27c815ff576fae5bb4bfa5e1322f2d0e/web/wp-includes/class-wp.php on line 231
Warning: preg_match(): Compilation failed: nothing to repeat at offset 1 in /home/clients/27c815ff576fae5bb4bfa5e1322f2d0e/web/wp-includes/class-wp.php on line 232

3) Disabled *all* plugins
-> I still get the 7 message pairs like this on most pages:
Warning: preg_match(): Compilation failed: nothing to repeat at offset 1 in /home/clients/27c815ff576fae5bb4bfa5e1322f2d0e/web/wp-includes/class-wp.php on line 231
Warning: preg_match(): Compilation failed: nothing to repeat at offset 1 in /home/clients/27c815ff576fae5bb4bfa5e1322f2d0e/web/wp-includes/class-wp.php on line 232

4) Enabled the plugins again
-> I still get the 7 message pairs like this on most pages:
Warning: preg_match(): Compilation failed: nothing to repeat at offset 1 in /home/clients/27c815ff576fae5bb4bfa5e1322f2d0e/web/wp-includes/class-wp.php on line 231
Warning: preg_match(): Compilation failed: nothing to repeat at offset 1 in /home/clients/27c815ff576fae5bb4bfa5e1322f2d0e/web/wp-includes/class-wp.php on line 232

5) Went to Events > Settings > Pages > Event Pages and set the ‘Display events as’ to ‘Pages’ (was set to ‘Posts’)
-> All is well, no errors

6) Went to Events > Settings > Pages > Event Pages and set the ‘Display events as’ to ‘Posts’
-> All is well, no errors

Summary
– Enabling Events Manager somehow created the problem.
– Disabling all plugins does not eliminate the problem.
– Fiddling with Events > Settings > Pages > Event Pages -> Display events does fix it, even with Event Manage installed

Somehow something happens to some data type processed in the loop in class-wp.php around line 23[12] when Events manager is enabled.

Markus

Thanks for the info. Can you confirm that you’ve tested with the default WordPress theme (to rule out a theme issue)?

Hy ,

I’ve the same issue on my website, I desactivated all my plugin, activate the default theme, then activate event manager and there is the warning :
https://cms-academy.fr/formations-joomla-lyon-nice-paris/

Thanks for help

PS : I also try to delete the plugin, then reinstall it

Hi !

Nothing new on this issue ?

Hi,

I’m getting the following error: possibly two errors repeating 4 times on all but my home landing page.

Warning: preg_match(): Unknown modifier ‘/’ in /home4/kharden1970/public_html/wp-includes/class-wp.php on line 231

Warning: preg_match(): Unknown modifier ‘/’ in /home4/kharden1970/public_html/wp-includes/class-wp.php on line 232

Warning: preg_match(): Unknown modifier ‘/’ in /home4/kharden1970/public_html/wp-includes/class-wp.php on line 231

Warning: preg_match(): Unknown modifier ‘/’ in /home4/kharden1970/public_html/wp-includes/class-wp.php on line 232

I’m getting the following error:

Warning: preg_match(): Unknown modifier ‘/’ in /home4/kharden1970/public_html/wp-includes/class-wp.php on line 231

Warning: preg_match(): Unknown modifier ‘/’ in /home4/kharden1970/public_html/wp-includes/class-wp.php on line 232

Warning: preg_match(): Unknown modifier ‘/’ in /home4/kharden1970/public_html/wp-includes/class-wp.php on line 231

Warning: preg_match(): Unknown modifier ‘/’ in /home4/kharden1970/public_html/wp-includes/class-wp.php on line 232

Can anyone help with this? The site was working fine, but this morning after a change to the post/blog menu and post page, I could not undo the problem.

I had the same error today. Checking all possibilities that have an influence on permalink structure should help.

e.g.
– WP permalink settings
– Yoast SEO permalink setting (category)
– Events-Manager permalink-settings (was the issue in my case)

Important: Deactivating or deleting plugins didn’t help. Just open the plugin’s permalink-settings and reconfirm them.

• This reply was modified 7 years, 10 months ago by Nnet.

Same problem solved by opening Events plugin settings and, without making any changes, clicking save changes in permalink slug area.

leighwp,
Thanks for the tip, I followed your advice and it fixed the preg_match errors on my client website.

Resaving worked for me too. I don’t know if this helps track down the problem, but I noticed it started to give an error after I made a change in Woocommerce. Specifically I had disabled the New email from being sent under Woocommerce > Settings > Email.