Bug report: Comment form disappears in multisite

I have a script for importing articles into a WordPress multisite. It’s a custom PHP script that is called directly from the command line and require wp-load.php at the very beginning to load the WordPress core.

For each article to be imported, the switch_to_blog() function is called to import the article into the correct site. The problem with wpdiscuz is that each time a post is created on a site other than the main site, the comment form disappears for all the articles on that site. To make it reappear, we have to save the wpdiscuz_form post again.

To resolve the issue within the import script, I have to reset WpdiscuzOptions->formContentTypeRel before each post, like this:

wpDiscuz()->options->formContentTypeRel = get_option("wpdiscuz_form_content_type_rel", []);

Here are the traces of what I observed while debugging this issue.

When the plugin loads, the WpdiscuzOptions->initFormRelations() method is called, which initializes WpdiscuzOptions->formContentTypeRel with a value from the main site. When switch_to_blog() is executed, this data is not reloaded to obtain the value for the site which has become the current site. Because of this, we end up executing the line unset($contentRel[$postType][$lang]); in the Form->setFormID() method, which causes comments to stop displaying on the article’s site until we save the wpdiscuz_form post of that site again.

I think the permanent fix in wpdiscuz should be to add a hook on switch_blog to reset the value of WpdiscuzOptions->formContentTypeRel each time a blog switch occurs.