From 834c29fbc68f85efdd34cbb253e429e86cc3bbf3 Mon Sep 17 00:00:00 2001
From: Boone Gorges <boonebgorges@git.wordpress.org>
Date: Thu, 13 Jul 2017 13:40:39 +0000
Subject: [PATCH] Taxonomy: Avoid duplicates when querying for terms in
 taxonomies registered with `$args` parameter.

[40514] introduced a bug that caused term queries to return some duplicates
when the `$taxonomies` array contained only taxonomies that were originally
registered with an `$args` array. We fix this bug by ensuring that
recursive `get_terms()` queries stop when all queried `$taxonomies` have
already been referenced.

Props bor0, atanasangelovdev.
Fixes #41010.

git-svn-id: https://develop.svn.wordpress.org/trunk@41037 602fd350-edb4-49c9-b593-d223f7449a82
---
 src/wp-includes/taxonomy.php                  |  5 ++-
 tests/phpunit/tests/term/wpGetObjectTerms.php | 36 +++++++++++++++++++
 2 files changed, 40 insertions(+), 1 deletion(-)

diff --git a/src/wp-includes/taxonomy.php b/src/wp-includes/taxonomy.php
index 05c6a10e8e..79d18f5fcd 100644
--- a/src/wp-includes/taxonomy.php
+++ b/src/wp-includes/taxonomy.php
@@ -1917,7 +1917,10 @@ function wp_get_object_terms($object_ids, $taxonomies, $args = array()) {
 	$args['taxonomy'] = $taxonomies;
 	$args['object_ids'] = $object_ids;
 
-	$terms = array_merge( $terms, get_terms( $args ) );
+	// Taxonomies registered without an 'args' param are handled here.
+	if ( ! empty( $taxonomies ) ) {
+		$terms = array_merge( $terms, get_terms( $args ) );
+	}
 
 	/**
 	 * Filters the terms for a given object or objects.
diff --git a/tests/phpunit/tests/term/wpGetObjectTerms.php b/tests/phpunit/tests/term/wpGetObjectTerms.php
index e527a601bf..5e3b8bcb9b 100644
--- a/tests/phpunit/tests/term/wpGetObjectTerms.php
+++ b/tests/phpunit/tests/term/wpGetObjectTerms.php
@@ -760,4 +760,40 @@ class Tests_Term_WpGetObjectTerms extends WP_UnitTestCase {
 		$args['orderby'] = 'term_order';
 		return $args;
 	}
+
+	/**
+	 * @ticket 41010
+	 */
+	public function test_duplicate_terms_should_not_be_returned_when_passed_multiple_taxonomies_registered_with_args_array() {
+		$taxonomy1 = 'wptests_tax';
+		$taxonomy2 = 'wptests_tax_2';
+
+		// Any non-empty 'args' array triggers the bug.
+		$taxonomy_arguments = array(
+			'args' => array( 0 ),
+		);
+
+		register_taxonomy( $taxonomy1, 'post', $taxonomy_arguments );
+		register_taxonomy( $taxonomy2, 'post', $taxonomy_arguments );
+
+		$post_id = self::factory()->post->create();
+		$term_1_id = self::factory()->term->create( array(
+			'taxonomy' => $taxonomy1,
+		) );
+		$term_2_id = self::factory()->term->create( array(
+			'taxonomy' => $taxonomy2,
+		) );
+
+		wp_set_object_terms( $post_id, $term_1_id, $taxonomy1 );
+		wp_set_object_terms( $post_id, $term_2_id, $taxonomy2 );
+
+		$expected = array( $term_1_id, $term_2_id );
+
+		$actual = wp_get_object_terms( $post_id, array( $taxonomy1, $taxonomy2 ), array(
+			'orderby' => 'term_id',
+			'fields' => 'ids',
+		) );
+
+		$this->assertEqualSets( $expected, $actual );
+	}
 }