Ticket #19954: 19954.diff

src/wp-includes/post.php

@@ -3031 +3031 @@
  *     @type string $post_mime_type        The mime type of the post. Default empty.
  *     @type string $guid                  Global Unique ID for referencing the post. Default empty.
  *     @type array  $post_category         Array of category names, slugs, or IDs.
- *                                         Defaults to value of the 'default_category' option.
+ *                                         Defaults to value of the 'default_category' option if inserting a new
+ *                                         post.
  *     @type array  $tax_input             Array of taxonomy terms keyed by their taxonomy name. Default empty.
  *     @type array  $meta_input            Array of post meta values keyed by their post meta key. Default empty.
  * }
@@ -3140 +3141 @@
                 $post_status = 'inherit';
         }
 
+        // Take note of whether updates to post categories were requested.
+        $update_post_categories = isset( $postarr['post_category'] );
+
         if ( ! empty( $postarr['post_category'] ) ) {
                 // Filter out empty terms.
                 $post_category = array_filter( $postarr['post_category'] );
@@ -3400 +3404 @@
                 clean_post_cache( $post_ID );
         }
 
+        /**
+         * Add/update categories if:
+         *     - we're inserting a new post
+         *     - we're updating a post and post_categories were specifically requested
+         */
         if ( is_object_in_taxonomy( $post_type, 'category' ) ) {
-                wp_set_post_categories( $post_ID, $post_category );
+                if ( ! $update || ( $update && $update_post_categories ) ) {
+                        wp_set_post_categories( $post_ID, $post_category );
+                }
         }
 
         if ( isset( $postarr['tags_input'] ) && is_object_in_taxonomy( $post_type, 'post_tag' ) ) {

tests/phpunit/tests/post/wpInsertPost.php

@@ -89 +89 @@
                 $this->assertEquals( 'about', get_post( $another_about_page_id )->post_name );
                 $this->assertEquals( 'about-2', get_post( $about_page_id )->post_name );
         }
+
+        function test_updating_a_post_should_not_trash_categories() {
+                // Create a post, and a term, and attach them.
+                $post_id = self::factory()->post->create( array(
+                        'post_type' => 'post',
+                        'post_title' => 'Post with categories',
+                        'post_status' => 'publish'
+                ) );
+                $term_id = self::factory()->term->create( array(
+                        'name' => 'Term',
+                        'taxonomy' => 'category'
+                ) );
+                wp_set_object_terms( $post_id, array( $term_id ), 'category' );
+
+                // Validate that the term got assigned.
+                $assigned_terms = wp_get_object_terms( array( $post_id ), array( 'category' ), array() );
+                $this->assertCount( 1, $assigned_terms );
+                $this->assertEquals( $term_id, $assigned_terms[0]->term_id );
+
+                // Update the post with no changes.
+                $post = get_post( $post_id );
+                wp_insert_post( $post );
+
+                // Validate that the term is still assigned.
+                $assigned_terms = wp_get_object_terms( array( $post_id ), array( 'category' ), array() );
+                $this->assertCount( 1, $assigned_terms );
+                $this->assertEquals( $term_id, $assigned_terms[0]->term_id );
+
+                // Remove the term from the post.
+                $post->post_category = array();
+                wp_insert_post($post);
+                $assigned_terms = wp_get_object_terms( array( $post_id ), array( 'category' ), array() );
+
+                // Validate that the post has had the default category assigned again.
+                $this->assertCount( 1, $assigned_terms );
+                $this->assertEquals( get_option( 'default_category' ), $assigned_terms[0]->term_id );
+        }
 }