"tax_query" parameter is ignored when "p" parameter is set in WP_Query

Question

I have a query object, where both tax_query and p parameters are set

[query] => Array
    (
        [tax_query] => Array
            (
                [0] => Array
                    (
                        [taxonomy] => destination_tag
                        [field] => slug
                        [terms] => Array
                            (
                                [0] => country
                            )

                    )

            )

        [post_type] => dc-location
        [lang] => en
        [posts_per_page] => 10
        [paged] => 1
        [p] => 7
    )

The resulting SQL query ignores the tax_query parameter

[request] => SELECT   wptests_posts.* FROM wptests_posts  WHERE 1=1  AND wptests_posts.ID = 7 AND wptests_posts.post_type = 'dc-location'  ORDER BY wptests_posts.post_date DESC

If I remove the p parameter, the query includes the tax query correctly. Is there a way to force the sql to parse tax_query even if p is defined?

Answer 1

p is a special argument in WP_Query in that it short-circuits most of the query parsing logic to request a single post.

In your case, I'd suggest using the post__in argument when you need to use tax_query at the same time.