After the update from 3.5 to 3.7 I get Warning: preg_split() expects parameter 2 to be string, array given on search

[goranpejovic]

Hello, I made custom search form and it worked fine until the update to 3.7. Here is the page in question: ​http://www.realestate.studio-morpheus.com/listings/?rentbuy=1&location%5B%5D=kotor&location%5B%5D=podgorica&property-type=&areamin=&areamax=&pricelow=&pricehigh=&site_section=listings

I am using GETs to send the search data and the one where I use array gives the error, other fields don't give the error. Furthermore the search works it just spits the warning and sets page title to 404.

[goranpejovic]

The error the page throws this error: Warning: preg_split() expects parameter 2 to be string, array given in /home/studiom4/public_html/realestate/wp-includes/query.php on line 1763

[SergeyBiryukov]

The warning comes from the secong preg_split() in the custom taxonomy handling block in WP_Query::parse_tax_query(): tags/3.7.1/src/wp-includes/query.php#L1738​.

Doesn't appear to be a regression. The code was introduced in [15613], modified in [15731], [15732], [15860], [15874], and [16259].

The patch on #17737 solves the issue by discarding a custom taxonomy query var if it's an array instead of a string.

[SergeyBiryukov]

Going to close as a duplicate of #17737 since it's a manifestation of the same issue.

[SergeyBiryukov]

#26665 was marked as a duplicate.