link-template.php: if ($x = $y ) vs if ($x == $y)

[danimalbrown]

While reading through the code I came across line 189 of wp-includes/link-template.php (WordPress 4.8.2):

if ( $parent = $category_object->parent )

I don't have a behavior to reflect this but it looks like the common bug where the incorrect single equals sign appears in a conditional. There should probably be 2 or 3 equal signs here.

[JPry]

Hi @danimalbrown, welcome to Trac! In this particular instance, the $parent variable is being set deliberately. It is subsequently used within the next line:

<?php
if ( $parent = $category_object->parent )
        $category = get_category_parents($parent, false, '/', true) . $category;

The $parent variable isn't used anywhere else within that function. This certainly is a confusing section of code, and it was a good idea to call it out as a potential issue.

Generally, something like this wouldn't be changed for the sole purpose of bringing it into line with the ​WordPress Coding Standards, but there may be room to eliminate the $parent variable in order to help clear up the confusion.

I'll upload a patch.

[danimalbrown]

Thanks @JPry for the clarification and for providing a patch. The patch definitely makes it more clear for someone looking over the code for the first time.

[swissspidy]

Please note that there's also #41057 to fix coding standards in core once and for all. Much easier than having dozens of very small tickets for things not really worth fixing on their own.

[SergeyBiryukov]

In 42378:

Permalinks: Remove unnecesary temporary variable in get_permalink().

Props JPry, danimalbrown.
Fixes #41981.