From fce8f2bf4dd19e56e9fed3a470c0224866c30edb Mon Sep 17 00:00:00 2001
From: Sergey Biryukov <sergeybiryukov@git.wordpress.org>
Date: Tue, 27 Oct 2020 16:40:35 +0000
Subject: [PATCH] Posts, Post Types: Check if taxonomy is set for the
 `tax_input` parameter of `wp_insert_post()`.

This avoids a PHP notice when creating a post with multiple taxonomies both having a default term.

Props yakimun, szaqal21, hareesh-pillai, audrasjb.
Fixes #51320.

git-svn-id: https://develop.svn.wordpress.org/trunk@49328 602fd350-edb4-49c9-b593-d223f7449a82
---
 src/wp-includes/post.php         |  2 +-
 tests/phpunit/tests/taxonomy.php | 32 +++++++++++++++++++++++++++-----
 2 files changed, 28 insertions(+), 6 deletions(-)

diff --git a/src/wp-includes/post.php b/src/wp-includes/post.php
index 92d16a6290..9c41c2ae5e 100644
--- a/src/wp-includes/post.php
+++ b/src/wp-includes/post.php
@@ -4091,7 +4091,7 @@ function wp_insert_post( $postarr, $wp_error = false, $fire_after_hooks = true )
 			if ( ! empty( $tax_object->default_term ) ) {
 
 				// Filter out empty terms.
-				if ( isset( $postarr['tax_input'] ) && is_array( $postarr['tax_input'][ $taxonomy ] ) ) {
+				if ( isset( $postarr['tax_input'][ $taxonomy ] ) && is_array( $postarr['tax_input'][ $taxonomy ] ) ) {
 					$postarr['tax_input'][ $taxonomy ] = array_filter( $postarr['tax_input'][ $taxonomy ] );
 				}
 
diff --git a/tests/phpunit/tests/taxonomy.php b/tests/phpunit/tests/taxonomy.php
index 5d39d000f1..886bc2b283 100644
--- a/tests/phpunit/tests/taxonomy.php
+++ b/tests/phpunit/tests/taxonomy.php
@@ -1007,14 +1007,14 @@ class Tests_Taxonomy extends WP_UnitTestCase {
 		);
 
 		// Add post.
-		$post_id = wp_insert_post(
+		$post_id = self::factory()->post->create(
 			array(
 				'post_title' => 'Foo',
 				'post_type'  => 'post',
 			)
 		);
 
-		// Test default category.
+		// Test default term.
 		$term = wp_get_post_terms( $post_id, $tax );
 		$this->assertSame( get_option( 'default_term_' . $tax ), $term[0]->term_id );
 
@@ -1028,16 +1028,18 @@ class Tests_Taxonomy extends WP_UnitTestCase {
 				'taxonomies' => array( $tax ),
 			)
 		);
-		$post_id = wp_insert_post(
+		$post_id = self::factory()->post->create(
 			array(
 				'post_title' => 'Foo',
 				'post_type'  => 'post-custom-tax',
 			)
 		);
-		$term    = wp_get_post_terms( $post_id, $tax );
+
+		// Test default term.
+		$term = wp_get_post_terms( $post_id, $tax );
 		$this->assertSame( get_option( 'default_term_' . $tax ), $term[0]->term_id );
 
-		// wp_set_object_terms shouldn't assign default category.
+		// wp_set_object_terms() should not assign default term.
 		wp_set_object_terms( $post_id, array(), $tax );
 		$term = wp_get_post_terms( $post_id, $tax );
 		$this->assertSame( array(), $term );
@@ -1046,6 +1048,26 @@ class Tests_Taxonomy extends WP_UnitTestCase {
 		$this->assertSame( get_option( 'default_term_' . $tax ), false );
 	}
 
+	/**
+	 * @ticket 51320
+	 */
+	function test_default_term_for_post_in_multiple_taxonomies() {
+		$post_type = 'test_post_type';
+		$tax1      = 'test_tax1';
+		$tax2      = 'test_tax2';
+
+		register_post_type( $post_type, array( 'taxonomies' => array( $tax1, $tax2 ) ) );
+		register_taxonomy( $tax1, $post_type, array( 'default_term' => 'term_1' ) );
+		register_taxonomy( $tax2, $post_type, array( 'default_term' => 'term_2' ) );
+
+		$post_id = self::factory()->post->create( array( 'post_type' => $post_type ) );
+
+		$taxonomies = get_post_taxonomies( $post_id );
+
+		$this->assertContains( $tax1, $taxonomies );
+		$this->assertContains( $tax2, $taxonomies );
+	}
+
 	/**
 	 * Ensure custom callbacks are used when registered.
 	 *