Prevent non-public taxonomies from registering aquery var.

[34247] made the 'public' paramater of `register_taxonomy()` work by blocking
requests for non-public taxonomy archives during `parse_request()`. Blocking
taxonomy archive requests this late means that it's impossible to register an
independent query var that matches the slug of a non-public taxonomy. By
moving the block to `register_taxonomy()` - not allowing these taxonomies to
register their query vars in the first place - we free up the slug for other
use. In addition, we free up a bit of processing (no need to look for the query
var in `parse_request()` and better parallel the way non-public post types
work. See `register_post_type()`.

Non-public taxonomy archives that are requested using `?taxonomy=tax_name` are
still blocked during `parse_request`. It's only custom query vars -
`?tax_name=term` - that are affected by this change.

Props mboynes.
Fixes #21949.

git-svn-id: https://develop.svn.wordpress.org/trunk@35333 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/class-wp.php

@@ -311,12 +311,10 @@ class WP {
 		// Don't allow non-public taxonomies to be queried from the front-end.
 		if ( ! is_admin() ) {
 			foreach ( get_taxonomies( array( 'public' => false ), 'objects' ) as $taxonomy => $t ) {
-				// Check first for taxonomy-specific query_var.
+				/*
-				if ( $t->query_var && isset( $this->query_vars[ $t->query_var ] ) ) {
+				 * Disallow when set to the 'taxonomy' query var.
-					unset( $this->query_vars[ $t->query_var ] );
+				 * Non-public taxonomies cannot register custom query vars. See register_taxonomy().
-				}
+				 */
-
-				// Next, check the 'taxonomy' query_var.
 				if ( isset( $this->query_vars['taxonomy'] ) && $taxonomy === $this->query_vars['taxonomy'] ) {
 					unset( $this->query_vars['taxonomy'], $this->query_vars['term'] );
 				}

src/wp-includes/taxonomy-functions.php

@@ -384,7 +384,7 @@ function register_taxonomy( $taxonomy, $object_type, $args = array() ) {
 		return new WP_Error( 'taxonomy_length_invalid', __( 'Taxonomy names must be between 1 and 32 characters in length.' ) );
 	}
 
-	if ( false !== $args['query_var'] && ! empty( $wp ) ) {
+	if ( false !== $args['query_var'] && false !== $args['public'] && ! empty( $wp ) ) {
 		if ( true === $args['query_var'] )
 			$args['query_var'] = $taxonomy;
 		else

tests/phpunit/includes/utils.php

@@ -357,7 +357,7 @@ function _cleanup_query_vars() {
 		unset( $GLOBALS[$v] );
 
 	foreach ( get_taxonomies( array() , 'objects' ) as $t ) {
-		if ( ! empty( $t->query_var ) )
+		if ( $t->public && ! empty( $t->query_var ) )
 			$GLOBALS['wp']->add_query_var( $t->query_var );
 	}
 

tests/phpunit/tests/taxonomy.php

@@ -463,6 +463,41 @@ class Tests_Taxonomy extends WP_UnitTestCase {
 		$this->assertFalse( is_tax( 'wptests_tax' ) );
 	}
 
+	/**
+	 * @ticket 21949
+	 */
+	public function test_it_should_be_possible_to_register_a_query_var_that_matches_the_name_of_a_nonpublic_taxonomy() {
+		global $wp;
+
+		register_taxonomy( 'wptests_tax', 'post', array(
+			'public' => false,
+		) );
+		$t = $this->factory->term->create_and_get( array(
+			'taxonomy' => 'wptests_tax',
+		) );
+
+		$p = $this->factory->post->create();
+		wp_set_object_terms( $p, $t->slug, 'wptests_tax' );
+
+		add_filter( 'do_parse_request', array( $this, 'register_query_var' ) );
+		$this->go_to( '/?wptests_tax=foo' );
+		remove_filter( 'do_parse_request', array( $this, 'register_query_var' ) );
+
+		// Not a taxonomy...
+		$this->assertFalse( is_tax( 'wptests_tax' ) );
+
+		// ...but query var works.
+		$this->assertSame( 'foo', $wp->query_vars['wptests_tax'] );
+	}
+
+	public static function register_query_var( $r ) {
+		global $wp;
+
+		$wp->add_query_var( 'wptests_tax' );
+
+		return $r;
+	}
+
 	/**
 	 * @ticket 21949
 	 */