Code Modernization: Fix null to non-nullable deprecations in `wp_xmlrpc_server::mw_newPost()`.

The `wp_xmlrpc_server::mw_newPost()` method creates a new post via `wp_insert_post()`, but the default/fallback values used in the function were not in line with the default/fallback values used in the `wp_insert_post()` function.

The `wp_insert_post()` function does a `wp_parse_args()` (array merge) of the received arguments with the defaults. If any of the received arguments are `null`, this would overwrite the default value, as seen in [https://3v4l.org/bfVlv array_merge() example], and lead to "passing null to non-nullable" deprecation notices on PHP 8.1 for certain arguments.

This commit:
* Ensures that all arguments are defined before they are `compact()`'ed together to the arguments array.
* Verifies that the default/fallback value of the arguments as set within the `wp_xmlrpc_server::mw_newPost()` method are the same as the default/fallback values used in the `wp_insert_post()` function.
* Verifies that arguments which do not have a default/fallback value defined in the `wp_insert_post()` function are handled correctly.
 * This was not the case for `$post_name`, which would previously already get an empty string default value in the `wp_xmlrpc_server::mw_newPost()` function, but then in the `wp_insert_post()` function, this would prevent the slug generation from being activated. Fixed now by setting the default in the `wp_xmlrpc_server::mw_newPost()` function to `null`.
 * The `page_template` argument was handled, but not documented in the `wp_insert_post()` function. The argument is now documented in the `wp_insert_post()` function DocBlock. Note: There are more than likely several other potential arguments missing from that list, but verifying the whole list is outside the scope of this particular commit.

Includes minor simplifications, such as:
* Setting a default ahead of an `if`, instead of in an `else` clause (as long as no function call is needed to set the default).
* Removing the unnecessary logic duplication in the `$post_status` switch.
* Using a combined concatenation + assignment operator for adding `$post_more`.

Fixes various errors along the lines of:
{{{
1) Tests_XMLRPC_mw_editPost::test_draft_not_prematurely_published
strpos(): Passing null to parameter #1 ($haystack) of type string is deprecated

/var/www/src/wp-includes/formatting.php:2497
/var/www/src/wp-includes/class-wp-hook.php:308
/var/www/src/wp-includes/plugin.php:205
/var/www/src/wp-includes/post.php:2835
/var/www/src/wp-includes/post.php:2720
/var/www/src/wp-includes/post.php:4066
/var/www/src/wp-includes/class-wp-xmlrpc-server.php:5616
/var/www/tests/phpunit/tests/xmlrpc/mw/editPost.php:315

...

23) Tests_XMLRPC_mw_editPost::test_draft_not_prematurely_published
json_decode(): Passing null to parameter #1 ($json) of type string is deprecated

/var/www/src/wp-includes/kses.php:2074
/var/www/src/wp-includes/class-wp-hook.php:307
/var/www/src/wp-includes/plugin.php:205
/var/www/src/wp-includes/post.php:2835
/var/www/src/wp-includes/post.php:2720
/var/www/src/wp-includes/post.php:4066
/var/www/src/wp-includes/class-wp-xmlrpc-server.php:5615
/var/www/tests/phpunit/tests/xmlrpc/mw/editPost.php:315
/var/www/vendor/bin/phpunit:123
}}}

Follow-up to [1563], [4793], [7900], [16824], [19848], [40677], [51968].

Props jrf.
See #55656.
Built from https://develop.svn.wordpress.org/trunk@54320


git-svn-id: http://core.svn.wordpress.org/trunk@53879 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/class-wp-xmlrpc-server.php

@@ -5399,30 +5399,27 @@ class wp_xmlrpc_server extends IXR_Server {
 
 		// Let WordPress generate the 'post_name' (slug) unless
 		// one has been provided.
-		$post_name = '';
+		$post_name = null;
 		if ( isset( $content_struct['wp_slug'] ) ) {
 			$post_name = $content_struct['wp_slug'];
 		}
 
 		// Only use a password if one was given.
+		$post_password = '';
 		if ( isset( $content_struct['wp_password'] ) ) {
 			$post_password = $content_struct['wp_password'];
-		} else {
-			$post_password = '';
 		}
 
 		// Only set a post parent if one was given.
+		$post_parent = 0;
 		if ( isset( $content_struct['wp_page_parent_id'] ) ) {
 			$post_parent = $content_struct['wp_page_parent_id'];
-		} else {
-			$post_parent = 0;
 		}
 
 		// Only set the 'menu_order' if it was given.
+		$menu_order = 0;
 		if ( isset( $content_struct['wp_page_order'] ) ) {
 			$menu_order = $content_struct['wp_page_order'];
-		} else {
-			$menu_order = 0;
 		}
 
 		$post_author = $user->ID;
@@ -5450,8 +5447,8 @@ class wp_xmlrpc_server extends IXR_Server {
 			$post_author = $content_struct['wp_author_id'];
 		}
 
-		$post_title   = isset( $content_struct['title'] ) ? $content_struct['title'] : null;
-		$post_content = isset( $content_struct['description'] ) ? $content_struct['description'] : null;
+		$post_title   = isset( $content_struct['title'] ) ? $content_struct['title'] : '';
+		$post_content = isset( $content_struct['description'] ) ? $content_struct['description'] : '';
 
 		$post_status = $publish ? 'publish' : 'draft';
 
@@ -5464,15 +5461,15 @@ class wp_xmlrpc_server extends IXR_Server {
 					$post_status = $content_struct[ "{$post_type}_status" ];
 					break;
 				default:
-					$post_status = $publish ? 'publish' : 'draft';
+					// Deliberably left empty.
 					break;
 			}
 		}
 
-		$post_excerpt = isset( $content_struct['mt_excerpt'] ) ? $content_struct['mt_excerpt'] : null;
-		$post_more    = isset( $content_struct['mt_text_more'] ) ? $content_struct['mt_text_more'] : null;
+		$post_excerpt = isset( $content_struct['mt_excerpt'] ) ? $content_struct['mt_excerpt'] : '';
+		$post_more    = isset( $content_struct['mt_text_more'] ) ? $content_struct['mt_text_more'] : '';
 
-		$tags_input = isset( $content_struct['mt_keywords'] ) ? $content_struct['mt_keywords'] : null;
+		$tags_input = isset( $content_struct['mt_keywords'] ) ? $content_struct['mt_keywords'] : array();
 
 		if ( isset( $content_struct['mt_allow_comments'] ) ) {
 			if ( ! is_numeric( $content_struct['mt_allow_comments'] ) ) {
@@ -5536,10 +5533,10 @@ class wp_xmlrpc_server extends IXR_Server {
 		}
 
 		if ( $post_more ) {
-			$post_content = $post_content . '<!--more-->' . $post_more;
+			$post_content .= '<!--more-->' . $post_more;
 		}
 
-		$to_ping = null;
+		$to_ping = '';
 		if ( isset( $content_struct['mt_tb_ping_urls'] ) ) {
 			$to_ping = $content_struct['mt_tb_ping_urls'];
 			if ( is_array( $to_ping ) ) {
@@ -5555,12 +5552,11 @@ class wp_xmlrpc_server extends IXR_Server {
 			$dateCreated = $content_struct['dateCreated']->getIso();
 		}
 
+		$post_date     = '';
+		$post_date_gmt = '';
 		if ( ! empty( $dateCreated ) ) {
 			$post_date     = iso8601_to_datetime( $dateCreated );
 			$post_date_gmt = iso8601_to_datetime( $dateCreated, 'gmt' );
-		} else {
-			$post_date     = '';
-			$post_date_gmt = '';
 		}
 
 		$post_category = array();
@@ -5786,7 +5782,7 @@ class wp_xmlrpc_server extends IXR_Server {
 			$menu_order = $content_struct['wp_page_order'];
 		}
 
-		$page_template = null;
+		$page_template = '';
 		if ( ! empty( $content_struct['wp_page_template'] ) && 'page' === $post_type ) {
 			$page_template = $content_struct['wp_page_template'];
 		}
@@ -5894,7 +5890,7 @@ class wp_xmlrpc_server extends IXR_Server {
 			$post_excerpt = $content_struct['mt_excerpt'];
 		}
 
-		$post_more = isset( $content_struct['mt_text_more'] ) ? $content_struct['mt_text_more'] : null;
+		$post_more = isset( $content_struct['mt_text_more'] ) ? $content_struct['mt_text_more'] : '';
 
 		$post_status = $publish ? 'publish' : 'draft';
 		if ( isset( $content_struct[ "{$post_type}_status" ] ) ) {
@@ -5911,7 +5907,7 @@ class wp_xmlrpc_server extends IXR_Server {
 			}
 		}
 
-		$tags_input = isset( $content_struct['mt_keywords'] ) ? $content_struct['mt_keywords'] : null;
+		$tags_input = isset( $content_struct['mt_keywords'] ) ? $content_struct['mt_keywords'] : array();
 
 		if ( 'publish' === $post_status || 'private' === $post_status ) {
 			if ( 'page' === $post_type && ! current_user_can( 'publish_pages' ) ) {
@@ -5925,7 +5921,7 @@ class wp_xmlrpc_server extends IXR_Server {
 			$post_content = $post_content . '<!--more-->' . $post_more;
 		}
 
-		$to_ping = null;
+		$to_ping = '';
 		if ( isset( $content_struct['mt_tb_ping_urls'] ) ) {
 			$to_ping = $content_struct['mt_tb_ping_urls'];
 			if ( is_array( $to_ping ) ) {

wp-includes/post.php

@@ -4034,6 +4034,7 @@ function wp_get_recent_posts( $args = array(), $output = ARRAY_A ) {
  *                                         child terms can have the same names with different parent terms,
  *                                         so the only way to connect them is using ID. Default empty.
  *     @type array  $meta_input            Array of post meta values keyed by their post meta key. Default empty.
+ *     @type string $page_template         Page template to use.
  * }
  * @param bool  $wp_error         Optional. Whether to return a WP_Error on failure. Default false.
  * @param bool  $fire_after_hooks Optional. Whether to fire the after insert hooks. Default true.

wp-includes/version.php

@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.1-beta1-54319';
+$wp_version = '6.1-beta1-54320';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.