From 60493f396843e80d19111f6ee1bc7d3c2f5efed3 Mon Sep 17 00:00:00 2001
From: Jb Audras <audrasjb@git.wordpress.org>
Date: Tue, 9 Aug 2022 10:21:32 +0000
Subject: [PATCH] Taxonomy: Prevent non string taxonomy names generating
 warnings or errors.

This changeset adds an `is_string( $taxonomy )` check to the condition in `taxonomy_exists()`, to ensure `false` is returned when the `$taxonomy` is not a string.

Follow-up to [35718].

Props costdev, peterwilsoncc, mukesh27.
Fixes #56338.
See #56336.


git-svn-id: https://develop.svn.wordpress.org/trunk@53869 602fd350-edb4-49c9-b593-d223f7449a82
---
 src/wp-includes/taxonomy.php     |  2 +-
 tests/phpunit/tests/taxonomy.php | 35 ++++++++++++++++++++++++++++++++
 2 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/src/wp-includes/taxonomy.php b/src/wp-includes/taxonomy.php
index 76a9ada576..6374d73bfa 100644
--- a/src/wp-includes/taxonomy.php
+++ b/src/wp-includes/taxonomy.php
@@ -337,7 +337,7 @@ function get_taxonomy( $taxonomy ) {
 function taxonomy_exists( $taxonomy ) {
 	global $wp_taxonomies;
 
-	return isset( $wp_taxonomies[ $taxonomy ] );
+	return is_string( $taxonomy ) && isset( $wp_taxonomies[ $taxonomy ] );
 }
 
 /**
diff --git a/tests/phpunit/tests/taxonomy.php b/tests/phpunit/tests/taxonomy.php
index 69dc1a8180..a4763fff9c 100644
--- a/tests/phpunit/tests/taxonomy.php
+++ b/tests/phpunit/tests/taxonomy.php
@@ -128,6 +128,41 @@ class Tests_Taxonomy extends WP_UnitTestCase {
 		$this->assertFalse( taxonomy_exists( null ) );
 	}
 
+	/**
+	 * Tests that `taxonomy_exists()` returns `false` when the `$taxonomy`
+	 * argument is not a string.
+	 *
+	 * @ticket 56338
+	 *
+	 * @covers :taxonomy_exists
+	 *
+	 * @dataProvider data_taxonomy_exists_should_return_false_with_non_string_taxonomy
+	 *
+	 * @param mixed $taxonomy The non-string taxonomy.
+	 */
+	public function test_taxonomy_exists_should_return_false_with_non_string_taxonomy( $taxonomy ) {
+		$this->assertFalse( taxonomy_exists( $taxonomy ) );
+	}
+
+	/**
+	 * Data provider with non-string values.
+	 *
+	 * @return array
+	 */
+	public function data_taxonomy_exists_should_return_false_with_non_string_taxonomy() {
+		return array(
+			'array'        => array( array() ),
+			'object'       => array( new stdClass() ),
+			'bool (true)'  => array( true ),
+			'bool (false)' => array( false ),
+			'null'         => array( null ),
+			'integer (0)'  => array( 0 ),
+			'integer (1)'  => array( 1 ),
+			'float (0.0)'  => array( 0.0 ),
+			'float (1.1)'  => array( 1.1 ),
+		);
+	}
+
 	public function test_is_taxonomy_hierarchical() {
 		$this->assertTrue( is_taxonomy_hierarchical( 'category' ) );
 		$this->assertFalse( is_taxonomy_hierarchical( 'post_tag' ) );