From 20edeb6e091c84c6a32f12831cbd64daa0abba7e Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@git.wordpress.org>
Date: Thu, 11 Aug 2022 20:00:10 +0000
Subject: [PATCH] Posts, Post Types: Prevent categories from being overwritten
 when updating a post using `wp_insert_post()`.

This prevents existing category relationships being overridden with the default category when none is provided in the post data.

Props markoheijnen, leewillis77, desrosj

Fixes #19954

Built from https://develop.svn.wordpress.org/trunk@53883


git-svn-id: http://core.svn.wordpress.org/trunk@53442 1a063a9b-81f0-0310-95a4-ce76da25c4cd
---
 wp-includes/post.php    | 2 ++
 wp-includes/version.php | 2 +-
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/wp-includes/post.php b/wp-includes/post.php
index d999c7bfeb..b434ae52e4 100644
--- a/wp-includes/post.php
+++ b/wp-includes/post.php
@@ -4142,6 +4142,8 @@ function wp_insert_post( $postarr, $wp_error = false, $fire_after_hooks = true )
 	if ( ! empty( $postarr['post_category'] ) ) {
 		// Filter out empty terms.
 		$post_category = array_filter( $postarr['post_category'] );
+	} elseif ( $update && ! isset( $postarr['post_category'] ) ) {
+		$post_category = $post_before->post_category;
 	}
 
 	// Make sure we set a valid category.
diff --git a/wp-includes/version.php b/wp-includes/version.php
index e55896f474..e8557ce318 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.1-alpha-53882';
+$wp_version = '6.1-alpha-53883';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.