odd behavior of exclude_tree parameter in wp_list_categories()

[tott]

When running a query such as

<?php wp_list_categories('title_li=&exclude_tree=1234&orderby=name&order=ASC'); ?>

the exclude_tree parameter is not obeyed as [10276] introduced a change that would overwrite it with the exclude parameter.

[tott]

Possible patch for exclude_tree problem in wp_list_categories()

[nacin]

We've had this this way since 2.7.x at this point, though the patch looks good. I can't see anything it would break. Actually, exclude_tree was added in r10276, so it's never worked properly -- we can probably punt this in that case.

[mhhenn]

exclude_tree doesn't work when hide_empty=0, it must must be set to 1 (hide empty)...

[webord]

Updating the .diff file for a refreshed one

[webord]

Refreshed the Patch.

[wonderboymusic]

Let's make a decision on the new patch

[wonderboymusic]

No unit tests

[SergeyBiryukov]

#28083 was marked as a duplicate.

[MikeHansenMe]

#28083 has unit tests

[MikeHansenMe]

12981.2.diff​ adds a single unit test and refreshes the patch.

[boonebgorges]

Thanks for the patches. It looks like the reason for the if ( true === $hierarchical ) block is to ensure that excluding a category also excludes its descendants. So wiping out $r['exclude'] altogether doesn't seem like an acceptable strategy. We want to allow for the possibility that someone would pass exclude *as well as* exclude_tree, and have both of them (and their descendants) excluded from results.

[boonebgorges]

In 34696:

Fix 'exclude_tree' in wp_list_categories().

The 'exclude_tree' parameter must be compatible with 'hierarchical';
previously, 'hierarchical' canceled it out. This changeset also makes it so
that 'exclude_tree' is compatible with 'exclude'. When both are passed, and
'hierarchical' is true, the descendant trees of terms in both parameters will
be excluded from matched terms.

Props tott, webord, MikeHansenMe.
Fixes #12981.