Capability limit on custom taxonomy does not allow editors to preview

[MikeNGarrett]

This is a super-niche bug, but I believe my potential solution makes post.js more hardy.

I'm registering a custom taxonomy with capabilities to limit it in the following way:

	'capabilities'      => array(
		'manage_terms'  => 'manage_options',
		'edit_terms'    => 'manage_options',
		'delete_terms'  => 'manage_options',
		'assign_terms'  => 'manage_options'
	),

This allows admins to manage the terms and all other users to view any terms that have been set.

The full register taxonomy:

register_taxonomy( 'migrated_category', array( 'post' ), array(
	'hierarchical'               => false,
	'public'                     => false,
	'show_ui'                    => true,
	'show_admin_column'          => false,
	'show_in_nav_menus'          => true,
	'show_tagcloud'              => false,
	'capabilities'      => array(
		'manage_terms'  => 'manage_options',
		'edit_terms'    => 'manage_options',
		'delete_terms'  => 'manage_options',
		'assign_terms'  => 'manage_options'
	),
	'labels'            => array(
		'name'                       => 'Migrated Categories',
		'singular_name'              => 'Migrated Category',
		'menu_name'                  => 'Migrated Categories',
	),
) );

As an editor, when you publish or save a new post, the terms for migrated categories are not set. This works fine except when attempting to preview this published or saved content. The following error is thrown in post.js

line 30: Uncaught TypeError: Cannot read property 'replace' of undefined

tagBox.flushTags() is not expecting both the existing tags and new tags to be undefined. There isn't a check here, so it errors out as tagBox.clean() gets called, expecting tags to be passed to it.

I'm attaching a patch that checks for typeof undefined on both tagBox.flushTags() and tagBox.clean(). It may be redundant since it seems like the flush and parse are the only things that call clean, but I'd rather be safe.

To note, removing capabilities from the taxonomy works as does having a term already set. Oddly enough, for admins in the same situation this is not a problem at all.

[MikeNGarrett]

post.js adding checks for typeof undefined

[DrewAPicture]

Hi Mike, welcome to Trac!

I can't seem to reproduce the TypeError you're getting. I did notice that with the patch applied the undefined keyword did start to appear in the taxonomy meta box which was ... interesting.

30859-post-js.diff​ still applies.

[valendesigns]

The patch no longer applies and needs a refresh. The code has been moved into the new tags-box.js file. As well, I can't reproduce the error and only see an empty meta box for Migrated Categories, even though I created a few taxonomies as an admin. Maybe I'm missing something in getting this setup. In any case a new patch is needed. Cheers!

[A5hleyRich]

I can't reproduce the TypeError either. However, as Drew has said when you hit 'Preview Changes' as an Editor, the undefined keyword is added as a tag. This happens on trunk without the patch applied.

[A5hleyRich]

Stop undefined appending to tags list.

[MikeNGarrett]

4.2 patch

[MikeNGarrett]

Same setup. Latest from trunk (4.2). I am getting the same result, but a different error in js:

undefined is not an object (evaluating 'tags.replace')

To note: this is the editor role previewing a post they've published or saved with a custom taxonomy.

Attached is a new patch to tags-box.js.

[boonebgorges]

Thanks, MikeNGarrett. I've reproduced the issue. I think you're right that the double check is redundant, so I'm going to trace it up to where the first undefined variable is found in flushTags(), and put the check there. (The call to clean() in parseTags() is never reached for a disabled taxonomy metabox - it's inside of an each() loop over an empty array.)

[boonebgorges]

In 31895:

When saving post, ensure that non-hierarchical taxonomy input is defined before attempting to parse it.

Taxonomy metaboxes that are disabled for the current user are included in the
post.php markup, but do not contain the 'newtag' field, and so should be
skipped when looping through the metaboxes to avoid invoking String methods
on a variable of type undefined.

Props MikeNGarrett, A5hleyRich.
Fixes #30859.