in_category function does no sanity checking

[tomsing1]

Using Wordpress 2.3 and themes "Fallseason 1.1" and "TerraFirma 3.4", I noticed the following warning displayed at the top of the page:

Warning: array_key_exists() [function.array-key-exists]: The first argument should be either a string or an integer in /wordpress/wp-includes/category-template.php on line 176

This problem was reported by others using different themes, too:
​http://wordpress.org/support/topic/135658
​http://wordpress.org/support/topic/132280

and it was suggested that this might be a bug in the "on_category" function itself, as it is not confined to any single theme.

[stormerider]

Patch to add sanity checking to $category value

[stormerider]

This is in_category, not on_category.

Some error checking should be performed to see if $category is null, and if so, return false. Diff attached.

[markjaquith]

Updated patch casts $category to an absolute integer, and then checks if it is zero. Should catch more errors, such as in_category('category-name')

Patches go into trunk first, and then are considered for backporting to 2.3.1

[Denis-de-Bernardy]

fixed in trunk