staylor / WordPress

wp-admin/includes/ajax-actions.php

<?php
/**
 * Administration API: Core Ajax handlers
 *
 * @package WordPress
 * @subpackage Administration
 * @since 2.1.0
 */

//
// No-privilege Ajax handlers.
//

/**
 * Ajax handler for the Heartbeat API in
 * the no-privilege context.
 *
 * Runs when the user is not logged in.
 *
 * @since 3.6.0
 */
function wp_ajax_nopriv_heartbeat() {
	$response = array();

	// screen_id is the same as $current_screen->id and the JS global 'pagenow'.
	if ( ! empty($_POST['screen_id']) )
		$screen_id = sanitize_key($_POST['screen_id']);
	else
		$screen_id = 'front';

	if ( ! empty($_POST['data']) ) {
		$data = wp_unslash( (array) $_POST['data'] );

		/**
		 * Filters Heartbeat Ajax response in no-privilege environments.
		 *
		 * @since 3.6.0
		 *
		 * @param array|object $response  The no-priv Heartbeat response object or array.
		 * @param array        $data      An array of data passed via $_POST.
		 * @param string       $screen_id The screen id.
		 */
		$response = apply_filters( 'heartbeat_nopriv_received', $response, $data, $screen_id );
	}

	/**
	 * Filters Heartbeat Ajax response when no data is passed.
	 *
	 * @since 3.6.0
	 *
	 * @param array|object $response  The Heartbeat response object or array.
	 * @param string       $screen_id The screen id.
	 */
	$response = apply_filters( 'heartbeat_nopriv_send', $response, $screen_id );

	/**
	 * Fires when Heartbeat ticks in no-privilege environments.
	 *
	 * Allows the transport to be easily replaced with long-polling.
	 *
	 * @since 3.6.0
	 *
	 * @param array|object $response  The no-priv Heartbeat response.
	 * @param string       $screen_id The screen id.
	 */
	do_action( 'heartbeat_nopriv_tick', $response, $screen_id );

	// Send the current time according to the server.
	$response['server_time'] = time();

	wp_send_json($response);
}

//
// GET-based Ajax handlers.
//

/**
 * Ajax handler for fetching a list table.
 *
 * @since 3.1.0
 *
 * @global WP_List_Table $wp_list_table
 */
function wp_ajax_fetch_list() {
	global $wp_list_table;

	$list_class = $_GET['list_args']['class'];
	check_ajax_referer( "fetch-list-$list_class", '_ajax_fetch_list_nonce' );

	$wp_list_table = _get_list_table( $list_class, array( 'screen' => $_GET['list_args']['screen']['id'] ) );
	if ( ! $wp_list_table )
		wp_die( 0 );

	if ( ! $wp_list_table->ajax_user_can() )
		wp_die( -1 );

	$wp_list_table->ajax_response();

	wp_die( 0 );
}

/**
 * Ajax handler for tag search.
 *
 * @since 3.1.0
 */
function wp_ajax_ajax_tag_search() {
	if ( ! isset( $_GET['tax'] ) ) {
		wp_die( 0 );
	}

	$taxonomy = sanitize_key( $_GET['tax'] );
	$tax = get_taxonomy( $taxonomy );
	if ( ! $tax ) {
		wp_die( 0 );
	}

	if ( ! current_user_can( $tax->cap->assign_terms ) ) {
		wp_die( -1 );
	}

	$s = wp_unslash( $_GET['q'] );

	$comma = _x( ',', 'tag delimiter' );
	if ( ',' !== $comma )
		$s = str_replace( $comma, ',', $s );
	if ( false !== strpos( $s, ',' ) ) {
		$s = explode( ',', $s );
		$s = $s[count( $s ) - 1];
	}
	$s = trim( $s );

	/**
	 * Filters the minimum number of characters required to fire a tag search via Ajax.
	 *
	 * @since 4.0.0
	 *
	 * @param int    $characters The minimum number of characters required. Default 2.
	 * @param object $tax        The taxonomy object.
	 * @param string $s          The search term.
	 */
	$term_search_min_chars = (int) apply_filters( 'term_search_min_chars', 2, $tax, $s );

	/*
	 * Require $term_search_min_chars chars for matching (default: 2)
	 * ensure it's a non-negative, non-zero integer.
	 */
	if ( ( $term_search_min_chars == 0 ) || ( strlen( $s ) < $term_search_min_chars ) ){
		wp_die();
	}

	$results = get_terms( $taxonomy, array( 'name__like' => $s, 'fields' => 'names', 'hide_empty' => false ) );

	echo join( $results, "\n" );
	wp_die();
}

/**
 * Ajax handler for compression testing.
 *
 * @since 3.1.0
 */
function wp_ajax_wp_compression_test() {
	if ( !current_user_can( 'manage_options' ) )
		wp_die( -1 );

	if ( ini_get('zlib.output_compression') || 'ob_gzhandler' == ini_get('output_handler') ) {
		update_site_option('can_compress_scripts', 0);
		wp_die( 0 );
	}

	if ( isset($_GET['test']) ) {
		header( 'Expires: Wed, 11 Jan 1984 05:00:00 GMT' );
		header( 'Last-Modified: ' . gmdate( 'D, d M Y H:i:s' ) . ' GMT' );
		header( 'Cache-Control: no-cache, must-revalidate, max-age=0' );
		header('Content-Type: application/javascript; charset=UTF-8');
		$force_gzip = ( defined('ENFORCE_GZIP') && ENFORCE_GZIP );
		$test_str = '"wpCompressionTest Lorem ipsum dolor sit amet consectetuer mollis sapien urna ut a. Eu nonummy condimentum fringilla tempor pretium platea vel nibh netus Maecenas. Hac molestie amet justo quis pellentesque est ultrices interdum nibh Morbi. Cras mattis pretium Phasellus ante ipsum ipsum ut sociis Suspendisse Lorem. Ante et non molestie. Porta urna Vestibulum egestas id congue nibh eu risus gravida sit. Ac augue auctor Ut et non a elit massa id sodales. Elit eu Nulla at nibh adipiscing mattis lacus mauris at tempus. Netus nibh quis suscipit nec feugiat eget sed lorem et urna. Pellentesque lacus at ut massa consectetuer ligula ut auctor semper Pellentesque. Ut metus massa nibh quam Curabitur molestie nec mauris congue. Volutpat molestie elit justo facilisis neque ac risus Ut nascetur tristique. Vitae sit lorem tellus et quis Phasellus lacus tincidunt nunc Fusce. Pharetra wisi Suspendisse mus sagittis libero lacinia Integer consequat ac Phasellus. Et urna ac cursus tortor aliquam Aliquam amet tellus volutpat Vestibulum. Justo interdum condimentum In augue congue tellus sollicitudin Quisque quis nibh."';

		 if ( 1 == $_GET['test'] ) {
		 	echo $test_str;
		 	wp_die();
		 } elseif ( 2 == $_GET['test'] ) {
			if ( !isset($_SERVER['HTTP_ACCEPT_ENCODING']) )
				wp_die( -1 );
			if ( false !== stripos( $_SERVER['HTTP_ACCEPT_ENCODING'], 'deflate') && function_exists('gzdeflate') && ! $force_gzip ) {
				header('Content-Encoding: deflate');
				$out = gzdeflate( $test_str, 1 );
			} elseif ( false !== stripos( $_SERVER['HTTP_ACCEPT_ENCODING'], 'gzip') && function_exists('gzencode') ) {
				header('Content-Encoding: gzip');
				$out = gzencode( $test_str, 1 );
			} else {
				wp_die( -1 );
			}
			echo $out;

The variable $out does not seem to be defined for all execution paths leading up to this point.

			wp_die();
		} elseif ( 'no' == $_GET['test'] ) {
			check_ajax_referer( 'update_can_compress_scripts' );
			update_site_option('can_compress_scripts', 0);
		} elseif ( 'yes' == $_GET['test'] ) {
			check_ajax_referer( 'update_can_compress_scripts' );
			update_site_option('can_compress_scripts', 1);
		}
	}

	wp_die( 0 );
}

/**
 * Ajax handler for image editor previews.
 *
 * @since 3.1.0
 */
function wp_ajax_imgedit_preview() {
	$post_id = intval($_GET['postid']);
	if ( empty($post_id) || !current_user_can('edit_post', $post_id) )
		wp_die( -1 );

	check_ajax_referer( "image_editor-$post_id" );

	include_once( ABSPATH . 'wp-admin/includes/image-edit.php' );
	if ( ! stream_preview_image($post_id) )
		wp_die( -1 );

	wp_die();
}

/**
 * Ajax handler for oEmbed caching.
 *
 * @since 3.1.0
 *
 * @global WP_Embed $wp_embed
 */
function wp_ajax_oembed_cache() {
	$GLOBALS['wp_embed']->cache_oembed( $_GET['post'] );
	wp_die( 0 );
}

/**
 * Ajax handler for user autocomplete.
 *
 * @since 3.4.0
 */
function wp_ajax_autocomplete_user() {
	if ( ! is_multisite() || ! current_user_can( 'promote_users' ) || wp_is_large_network( 'users' ) )
		wp_die( -1 );

	/** This filter is documented in wp-admin/user-new.php */
	if ( ! is_super_admin() && ! apply_filters( 'autocomplete_users_for_site_admins', false ) )
		wp_die( -1 );

	$return = array();

	// Check the type of request
	// Current allowed values are `add` and `search`
	if ( isset( $_REQUEST['autocomplete_type'] ) && 'search' === $_REQUEST['autocomplete_type'] ) {
		$type = $_REQUEST['autocomplete_type'];
	} else {
		$type = 'add';
	}

	// Check the desired field for value
	// Current allowed values are `user_email` and `user_login`
	if ( isset( $_REQUEST['autocomplete_field'] ) && 'user_email' === $_REQUEST['autocomplete_field'] ) {
		$field = $_REQUEST['autocomplete_field'];
	} else {
		$field = 'user_login';
	}

	// Exclude current users of this blog
	if ( isset( $_REQUEST['site_id'] ) ) {
		$id = absint( $_REQUEST['site_id'] );
	} else {
		$id = get_current_blog_id();
	}

	$include_blog_users = ( $type == 'search' ? get_users( array( 'blog_id' => $id, 'fields' => 'ID' ) ) : array() );
	$exclude_blog_users = ( $type == 'add' ? get_users( array( 'blog_id' => $id, 'fields' => 'ID' ) ) : array() );

	$users = get_users( array(
		'blog_id' => false,
		'search'  => '*' . $_REQUEST['term'] . '*',
		'include' => $include_blog_users,
		'exclude' => $exclude_blog_users,
		'search_columns' => array( 'user_login', 'user_nicename', 'user_email' ),
	) );

	foreach ( $users as $user ) {
		$return[] = array(
			/* translators: 1: user_login, 2: user_email */
			'label' => sprintf( _x( '%1$s (%2$s)', 'user autocomplete result' ), $user->user_login, $user->user_email ),
			'value' => $user->$field,
		);
	}

	wp_die( wp_json_encode( $return ) );

It seems like wp_json_encode($return) targeting wp_json_encode() can also be of type false; however, wp_die() does only seem to accept string|object<WP_Error>, did you maybe forget to handle an error condition?

}

/**
 * Ajax handler for dashboard widgets.
 *
 * @since 3.4.0
 */
function wp_ajax_dashboard_widgets() {
	require_once ABSPATH . 'wp-admin/includes/dashboard.php';

	$pagenow = $_GET['pagenow'];
	if ( $pagenow === 'dashboard-user' || $pagenow === 'dashboard-network' || $pagenow === 'dashboard' ) {
		set_current_screen( $pagenow );
	}

	switch ( $_GET['widget'] ) {
		case 'dashboard_primary' :
			wp_dashboard_primary();
			break;
	}
	wp_die();
}

/**
 * Ajax handler for Customizer preview logged-in status.
 *
 * @since 3.4.0
 */
function wp_ajax_logged_in() {
	wp_die( 1 );
}

//
// Ajax helpers.
//

/**
 * Sends back current comment total and new page links if they need to be updated.
 *
 * Contrary to normal success Ajax response ("1"), die with time() on success.
 *
 * @access private
 * @since 2.7.0
 *
 * @param int $comment_id
 * @param int $delta
 */
function _wp_ajax_delete_comment_response( $comment_id, $delta = -1 ) {
	$total    = isset( $_POST['_total'] )    ? (int) $_POST['_total']    : 0;
	$per_page = isset( $_POST['_per_page'] ) ? (int) $_POST['_per_page'] : 0;
	$page     = isset( $_POST['_page'] )     ? (int) $_POST['_page']     : 0;
	$url      = isset( $_POST['_url'] )      ? esc_url_raw( $_POST['_url'] ) : '';

	// JS didn't send us everything we need to know. Just die with success message
	if ( ! $total || ! $per_page || ! $page || ! $url ) {
		$time           = time();
		$comment        = get_comment( $comment_id );
		$comment_status = '';
		$comment_link   = '';

		if ( $comment ) {
			$comment_status = $comment->comment_approved;
		}

		if ( 1 === (int) $comment_status ) {
			$comment_link = get_comment_link( $comment );
		}

		$counts = wp_count_comments();

		$x = new WP_Ajax_Response( array(
			'what' => 'comment',
			// Here for completeness - not used.
			'id' => $comment_id,
			'supplemental' => array(
				'status' => $comment_status,
				'postId' => $comment ? $comment->comment_post_ID : '',
				'time' => $time,
				'in_moderation' => $counts->moderated,
				'i18n_comments_text' => sprintf(
					_n( '%s Comment', '%s Comments', $counts->approved ),
					number_format_i18n( $counts->approved )
				),
				'i18n_moderation_text' => sprintf(
					_nx( '%s in moderation', '%s in moderation', $counts->moderated, 'comments' ),
					number_format_i18n( $counts->moderated )
				),
				'comment_link' => $comment_link,
			)
		) );
		$x->send();
	}

	$total += $delta;
	if ( $total < 0 )
		$total = 0;

	// Only do the expensive stuff on a page-break, and about 1 other time per page
	if ( 0 == $total % $per_page || 1 == mt_rand( 1, $per_page ) ) {
		$post_id = 0;
		// What type of comment count are we looking for?
		$status = 'all';
		$parsed = parse_url( $url );
		if ( isset( $parsed['query'] ) ) {
			parse_str( $parsed['query'], $query_vars );
			if ( !empty( $query_vars['comment_status'] ) )
				$status = $query_vars['comment_status'];
			if ( !empty( $query_vars['p'] ) )
				$post_id = (int) $query_vars['p'];
			if ( ! empty( $query_vars['comment_type'] ) )
				$type = $query_vars['comment_type'];
		}

		if ( empty( $type ) ) {
			// Only use the comment count if not filtering by a comment_type.
			$comment_count = wp_count_comments($post_id);

			// We're looking for a known type of comment count.
			if ( isset( $comment_count->$status ) ) {
				$total = $comment_count->$status;
			}
		}
		// Else use the decremented value from above.
	}

	// The time since the last comment count.
	$time = time();
	$comment = get_comment( $comment_id );

	$x = new WP_Ajax_Response( array(
		'what' => 'comment',
		// Here for completeness - not used.
		'id' => $comment_id,
		'supplemental' => array(
			'status' => $comment ? $comment->comment_approved : '',
			'postId' => $comment ? $comment->comment_post_ID : '',
			'total_items_i18n' => sprintf( _n( '%s item', '%s items', $total ), number_format_i18n( $total ) ),
			'total_pages' => ceil( $total / $per_page ),
			'total_pages_i18n' => number_format_i18n( ceil( $total / $per_page ) ),
			'total' => $total,
			'time' => $time
		)
	) );
	$x->send();
}

//
// POST-based Ajax handlers.
//

/**
 * Ajax handler for adding a hierarchical term.
 *
 * @access private
 * @since 3.1.0
 */
function _wp_ajax_add_hierarchical_term() {
	$action = $_POST['action'];
	$taxonomy = get_taxonomy(substr($action, 4));
	check_ajax_referer( $action, '_ajax_nonce-add-' . $taxonomy->name );
	if ( !current_user_can( $taxonomy->cap->edit_terms ) )
		wp_die( -1 );
	$names = explode(',', $_POST['new'.$taxonomy->name]);
	$parent = isset($_POST['new'.$taxonomy->name.'_parent']) ? (int) $_POST['new'.$taxonomy->name.'_parent'] : 0;
	if ( 0 > $parent )
		$parent = 0;
	if ( $taxonomy->name == 'category' )
		$post_category = isset($_POST['post_category']) ? (array) $_POST['post_category'] : array();
	else
		$post_category = ( isset($_POST['tax_input']) && isset($_POST['tax_input'][$taxonomy->name]) ) ? (array) $_POST['tax_input'][$taxonomy->name] : array();
	$checked_categories = array_map( 'absint', (array) $post_category );
	$popular_ids = wp_popular_terms_checklist($taxonomy->name, 0, 10, false);

	foreach ( $names as $cat_name ) {
		$cat_name = trim($cat_name);
		$category_nicename = sanitize_title($cat_name);
		if ( '' === $category_nicename )
			continue;
		if ( !$cat_id = term_exists( $cat_name, $taxonomy->name, $parent ) )
			$cat_id = wp_insert_term( $cat_name, $taxonomy->name, array( 'parent' => $parent ) );
		if ( is_wp_error( $cat_id ) ) {
			continue;
		} elseif ( is_array( $cat_id ) ) {
			$cat_id = $cat_id['term_id'];
		}
		$checked_categories[] = $cat_id;
		if ( $parent ) // Do these all at once in a second
			continue;

		ob_start();

		wp_terms_checklist( 0, array( 'taxonomy' => $taxonomy->name, 'descendants_and_self' => $cat_id, 'selected_cats' => $checked_categories, 'popular_cats' => $popular_ids ));

		$data = ob_get_clean();

		$add = array(
			'what' => $taxonomy->name,
			'id' => $cat_id,
			'data' => str_replace( array("\n", "\t"), '', $data),
			'position' => -1
		);
	}

	if ( $parent ) { // Foncy - replace the parent and all its children
		$parent = get_term( $parent, $taxonomy->name );
		$term_id = $parent->term_id;

		while ( $parent->parent ) { // get the top parent
			$parent = get_term( $parent->parent, $taxonomy->name );
			if ( is_wp_error( $parent ) )
				break;
			$term_id = $parent->term_id;
		}

		ob_start();

		wp_terms_checklist( 0, array('taxonomy' => $taxonomy->name, 'descendants_and_self' => $term_id, 'selected_cats' => $checked_categories, 'popular_cats' => $popular_ids));

		$data = ob_get_clean();

		$add = array(
			'what' => $taxonomy->name,
			'id' => $term_id,
			'data' => str_replace( array("\n", "\t"), '', $data),
			'position' => -1
		);
	}

	ob_start();

	wp_dropdown_categories( array(
		'taxonomy' => $taxonomy->name, 'hide_empty' => 0, 'name' => 'new'.$taxonomy->name.'_parent', 'orderby' => 'name',
		'hierarchical' => 1, 'show_option_none' => '&mdash; '.$taxonomy->labels->parent_item.' &mdash;'
	) );

	$sup = ob_get_clean();

	$add['supplemental'] = array( 'newcat_parent' => $sup );

The variable $add does not seem to be defined for all execution paths leading up to this point.

	$x = new WP_Ajax_Response( $add );
	$x->send();
}

/**
 * Ajax handler for deleting a comment.
 *
 * @since 3.1.0
 */
function wp_ajax_delete_comment() {
	$id = isset( $_POST['id'] ) ? (int) $_POST['id'] : 0;

	if ( !$comment = get_comment( $id ) )
		wp_die( time() );
	if ( ! current_user_can( 'edit_comment', $comment->comment_ID ) )
		wp_die( -1 );

	check_ajax_referer( "delete-comment_$id" );
	$status = wp_get_comment_status( $comment );

	$delta = -1;
	if ( isset($_POST['trash']) && 1 == $_POST['trash'] ) {
		if ( 'trash' == $status )
			wp_die( time() );
		$r = wp_trash_comment( $comment );
	} elseif ( isset($_POST['untrash']) && 1 == $_POST['untrash'] ) {
		if ( 'trash' != $status )
			wp_die( time() );
		$r = wp_untrash_comment( $comment );
		if ( ! isset( $_POST['comment_status'] ) || $_POST['comment_status'] != 'trash' ) // undo trash, not in trash
			$delta = 1;
	} elseif ( isset($_POST['spam']) && 1 == $_POST['spam'] ) {
		if ( 'spam' == $status )
			wp_die( time() );
		$r = wp_spam_comment( $comment );
	} elseif ( isset($_POST['unspam']) && 1 == $_POST['unspam'] ) {
		if ( 'spam' != $status )
			wp_die( time() );
		$r = wp_unspam_comment( $comment );
		if ( ! isset( $_POST['comment_status'] ) || $_POST['comment_status'] != 'spam' ) // undo spam, not in spam
			$delta = 1;
	} elseif ( isset($_POST['delete']) && 1 == $_POST['delete'] ) {
		$r = wp_delete_comment( $comment );
	} else {
		wp_die( -1 );
	}

	if ( $r ) // Decide if we need to send back '1' or a more complicated response including page links and comment counts

The variable $r does not seem to be defined for all execution paths leading up to this point.

		_wp_ajax_delete_comment_response( $comment->comment_ID, $delta );
	wp_die( 0 );
}

/**
 * Ajax handler for deleting a tag.
 *
 * @since 3.1.0
 */
function wp_ajax_delete_tag() {
	$tag_id = (int) $_POST['tag_ID'];
	check_ajax_referer( "delete-tag_$tag_id" );

	$taxonomy = !empty($_POST['taxonomy']) ? $_POST['taxonomy'] : 'post_tag';
	$tax = get_taxonomy($taxonomy);

	if ( !current_user_can( $tax->cap->delete_terms ) )
		wp_die( -1 );

	$tag = get_term( $tag_id, $taxonomy );
	if ( !$tag || is_wp_error( $tag ) )
		wp_die( 1 );

	if ( wp_delete_term($tag_id, $taxonomy))
		wp_die( 1 );
	else
		wp_die( 0 );
}

/**
 * Ajax handler for deleting a link.
 *
 * @since 3.1.0
 */
function wp_ajax_delete_link() {

This function seems to be duplicated in your project.

	$id = isset( $_POST['id'] ) ? (int) $_POST['id'] : 0;

	check_ajax_referer( "delete-bookmark_$id" );
	if ( !current_user_can( 'manage_links' ) )
		wp_die( -1 );

	$link = get_bookmark( $id );
	if ( !$link || is_wp_error( $link ) )
		wp_die( 1 );

	if ( wp_delete_link( $id ) )
		wp_die( 1 );
	else
		wp_die( 0 );
}

/**
 * Ajax handler for deleting meta.
 *
 * @since 3.1.0
 */
function wp_ajax_delete_meta() {
	$id = isset( $_POST['id'] ) ? (int) $_POST['id'] : 0;

	check_ajax_referer( "delete-meta_$id" );
	if ( !$meta = get_metadata_by_mid( 'post', $id ) )
		wp_die( 1 );

	if ( is_protected_meta( $meta->meta_key, 'post' ) || ! current_user_can( 'delete_post_meta',  $meta->post_id, $meta->meta_key ) )
		wp_die( -1 );
	if ( delete_meta( $meta->meta_id ) )
		wp_die( 1 );
	wp_die( 0 );
}

/**
 * Ajax handler for deleting a post.
 *
 * @since 3.1.0
 *
 * @param string $action Action to perform.
 */
function wp_ajax_delete_post( $action ) {

This function seems to be duplicated in your project.

	if ( empty( $action ) )
		$action = 'delete-post';
	$id = isset( $_POST['id'] ) ? (int) $_POST['id'] : 0;

	check_ajax_referer( "{$action}_$id" );
	if ( !current_user_can( 'delete_post', $id ) )
		wp_die( -1 );

	if ( !get_post( $id ) )
		wp_die( 1 );

	if ( wp_delete_post( $id ) )
		wp_die( 1 );
	else
		wp_die( 0 );
}

/**
 * Ajax handler for sending a post to the trash.
 *
 * @since 3.1.0
 *
 * @param string $action Action to perform.
 */
function wp_ajax_trash_post( $action ) {
	if ( empty( $action ) )
		$action = 'trash-post';
	$id = isset( $_POST['id'] ) ? (int) $_POST['id'] : 0;

	check_ajax_referer( "{$action}_$id" );
	if ( !current_user_can( 'delete_post', $id ) )
		wp_die( -1 );

	if ( !get_post( $id ) )
		wp_die( 1 );

	if ( 'trash-post' == $action )
		$done = wp_trash_post( $id );
	else
		$done = wp_untrash_post( $id );

	if ( $done )
		wp_die( 1 );

	wp_die( 0 );
}

/**
 * Ajax handler to restore a post from the trash.
 *
 * @since 3.1.0
 *
 * @param string $action Action to perform.
 */
function wp_ajax_untrash_post( $action ) {
	if ( empty( $action ) )
		$action = 'untrash-post';
	wp_ajax_trash_post( $action );
}

/**
 * @since 3.1.0
 *
 * @param string $action
 */
function wp_ajax_delete_page( $action ) {

This function seems to be duplicated in your project.

	if ( empty( $action ) )
		$action = 'delete-page';
	$id = isset( $_POST['id'] ) ? (int) $_POST['id'] : 0;

	check_ajax_referer( "{$action}_$id" );
	if ( !current_user_can( 'delete_page', $id ) )
		wp_die( -1 );

	if ( ! get_post( $id ) )
		wp_die( 1 );

	if ( wp_delete_post( $id ) )
		wp_die( 1 );
	else
		wp_die( 0 );
}

/**
 * Ajax handler to dim a comment.
 *
 * @since 3.1.0
 */
function wp_ajax_dim_comment() {
	$id = isset( $_POST['id'] ) ? (int) $_POST['id'] : 0;

	if ( !$comment = get_comment( $id ) ) {
		$x = new WP_Ajax_Response( array(
			'what' => 'comment',
			'id' => new WP_Error('invalid_comment', sprintf(__('Comment %d does not exist'), $id))
		) );
		$x->send();
	}

	if ( ! current_user_can( 'edit_comment', $comment->comment_ID ) && ! current_user_can( 'moderate_comments' ) )
		wp_die( -1 );

	$current = wp_get_comment_status( $comment );
	if ( isset( $_POST['new'] ) && $_POST['new'] == $current )
		wp_die( time() );

	check_ajax_referer( "approve-comment_$id" );
	if ( in_array( $current, array( 'unapproved', 'spam' ) ) ) {
		$result = wp_set_comment_status( $comment, 'approve', true );
	} else {
		$result = wp_set_comment_status( $comment, 'hold', true );
	}

	if ( is_wp_error($result) ) {
		$x = new WP_Ajax_Response( array(
			'what' => 'comment',
			'id' => $result
		) );
		$x->send();
	}

	// Decide if we need to send back '1' or a more complicated response including page links and comment counts
	_wp_ajax_delete_comment_response( $comment->comment_ID );
	wp_die( 0 );
}

/**
 * Ajax handler for deleting a link category.
 *
 * @since 3.1.0
 *
 * @param string $action Action to perform.
 */
function wp_ajax_add_link_category( $action ) {
	if ( empty( $action ) )
		$action = 'add-link-category';
	check_ajax_referer( $action );
	if ( !current_user_can( 'manage_categories' ) )
		wp_die( -1 );
	$names = explode(',', wp_unslash( $_POST['newcat'] ) );
	$x = new WP_Ajax_Response();
	foreach ( $names as $cat_name ) {
		$cat_name = trim($cat_name);
		$slug = sanitize_title($cat_name);
		if ( '' === $slug )
			continue;
		if ( !$cat_id = term_exists( $cat_name, 'link_category' ) )
			$cat_id = wp_insert_term( $cat_name, 'link_category' );
		if ( is_wp_error( $cat_id ) ) {
			continue;
		} elseif ( is_array( $cat_id ) ) {
			$cat_id = $cat_id['term_id'];
		}
		$cat_name = esc_html( $cat_name );
		$x->add( array(
			'what' => 'link-category',
			'id' => $cat_id,
			'data' => "<li id='link-category-$cat_id'><label for='in-link-category-$cat_id' class='selectit'><input value='" . esc_attr($cat_id) . "' type='checkbox' checked='checked' name='link_category[]' id='in-link-category-$cat_id'/> $cat_name</label></li>",
			'position' => -1
		) );
	}
	$x->send();
}

/**
 * Ajax handler to add a tag.
 *
 * @since 3.1.0
 *
 * @global WP_List_Table $wp_list_table
 */
function wp_ajax_add_tag() {
	global $wp_list_table;

	check_ajax_referer( 'add-tag', '_wpnonce_add-tag' );
	$taxonomy = !empty($_POST['taxonomy']) ? $_POST['taxonomy'] : 'post_tag';
	$tax = get_taxonomy($taxonomy);

	if ( !current_user_can( $tax->cap->edit_terms ) )
		wp_die( -1 );

	$x = new WP_Ajax_Response();

	$tag = wp_insert_term($_POST['tag-name'], $taxonomy, $_POST );

	if ( !$tag || is_wp_error($tag) || (!$tag = get_term( $tag['term_id'], $taxonomy )) ) {
		$message = __('An error has occurred. Please reload the page and try again.');
		if ( is_wp_error($tag) && $tag->get_error_message() )
			$message = $tag->get_error_message();

The method get_error_message does only exist in WP_Error, but not in WP_Term.

		$x->add( array(
			'what' => 'taxonomy',
			'data' => new WP_Error('error', $message )
		) );
		$x->send();
	}

	$wp_list_table = _get_list_table( 'WP_Terms_List_Table', array( 'screen' => $_POST['screen'] ) );

	$level = 0;
	if ( is_taxonomy_hierarchical($taxonomy) ) {
		$level = count( get_ancestors( $tag->term_id, $taxonomy, 'taxonomy' ) );
		ob_start();
		$wp_list_table->single_row( $tag, $level );
		$noparents = ob_get_clean();
	}

	ob_start();
	$wp_list_table->single_row( $tag );
	$parents = ob_get_clean();

	$x->add( array(
		'what' => 'taxonomy',
		'supplemental' => compact('parents', 'noparents')
	) );
	$x->add( array(
		'what' => 'term',
		'position' => $level,
		'supplemental' => (array) $tag
	) );
	$x->send();
}

/**
 * Ajax handler for getting a tagcloud.
 *
 * @since 3.1.0
 */
function wp_ajax_get_tagcloud() {
	if ( ! isset( $_POST['tax'] ) ) {
		wp_die( 0 );
	}

	$taxonomy = sanitize_key( $_POST['tax'] );
	$tax = get_taxonomy( $taxonomy );
	if ( ! $tax ) {
		wp_die( 0 );
	}

	if ( ! current_user_can( $tax->cap->assign_terms ) ) {
		wp_die( -1 );
	}

	$tags = get_terms( $taxonomy, array( 'number' => 45, 'orderby' => 'count', 'order' => 'DESC' ) );

	if ( empty( $tags ) )
		wp_die( $tax->labels->not_found );

	if ( is_wp_error( $tags ) )
		wp_die( $tags->get_error_message() );

	foreach ( $tags as $key => $tag ) {

The expression $tags of type array|integer|object<WP_Error> is not guaranteed to be traversable. How about adding an additional type check?

		$tags[ $key ]->link = '#';
		$tags[ $key ]->id = $tag->term_id;
	}

	// We need raw tag names here, so don't filter the output
	$return = wp_generate_tag_cloud( $tags, array('filter' => 0) );

	if ( empty($return) )
		wp_die( 0 );

	echo $return;

	wp_die();
}

/**
 * Ajax handler for getting comments.
 *
 * @since 3.1.0
 *
 * @global WP_List_Table $wp_list_table
 * @global int           $post_id
 *
 * @param string $action Action to perform.
 */
function wp_ajax_get_comments( $action ) {
	global $wp_list_table, $post_id;
	if ( empty( $action ) )
		$action = 'get-comments';

	check_ajax_referer( $action );

	if ( empty( $post_id ) && ! empty( $_REQUEST['p'] ) ) {
		$id = absint( $_REQUEST['p'] );
		if ( ! empty( $id ) )
			$post_id = $id;
	}

	if ( empty( $post_id ) )
		wp_die( -1 );

	$wp_list_table = _get_list_table( 'WP_Post_Comments_List_Table', array( 'screen' => 'edit-comments' ) );

	if ( ! current_user_can( 'edit_post', $post_id ) )
		wp_die( -1 );

	$wp_list_table->prepare_items();

	if ( !$wp_list_table->has_items() )
		wp_die( 1 );

	$x = new WP_Ajax_Response();
	ob_start();
	foreach ( $wp_list_table->items as $comment ) {
		if ( ! current_user_can( 'edit_comment', $comment->comment_ID ) && 0 === $comment->comment_approved )
			continue;
		get_comment( $comment );
		$wp_list_table->single_row( $comment );
	}
	$comment_list_item = ob_get_clean();

	$x->add( array(
		'what' => 'comments',
		'data' => $comment_list_item
	) );
	$x->send();
}

/**
 * Ajax handler for replying to a comment.
 *
 * @since 3.1.0
 *
 * @global WP_List_Table $wp_list_table
 *
 * @param string $action Action to perform.
 */
function wp_ajax_replyto_comment( $action ) {
	global $wp_list_table;
	if ( empty( $action ) )
		$action = 'replyto-comment';

	check_ajax_referer( $action, '_ajax_nonce-replyto-comment' );

	$comment_post_ID = (int) $_POST['comment_post_ID'];
	$post = get_post( $comment_post_ID );
	if ( ! $post )
		wp_die( -1 );

	if ( !current_user_can( 'edit_post', $comment_post_ID ) )
		wp_die( -1 );

	if ( empty( $post->post_status ) )
		wp_die( 1 );
	elseif ( in_array($post->post_status, array('draft', 'pending', 'trash') ) )
		wp_die( __('ERROR: you are replying to a comment on a draft post.') );

	$user = wp_get_current_user();
	if ( $user->exists() ) {
		$user_ID = $user->ID;
		$comment_author       = wp_slash( $user->display_name );
		$comment_author_email = wp_slash( $user->user_email );
		$comment_author_url   = wp_slash( $user->user_url );
		$comment_content      = trim( $_POST['content'] );
		$comment_type         = isset( $_POST['comment_type'] ) ? trim( $_POST['comment_type'] ) : '';
		if ( current_user_can( 'unfiltered_html' ) ) {
			if ( ! isset( $_POST['_wp_unfiltered_html_comment'] ) )
				$_POST['_wp_unfiltered_html_comment'] = '';

			if ( wp_create_nonce( 'unfiltered-html-comment' ) != $_POST['_wp_unfiltered_html_comment'] ) {
				kses_remove_filters(); // start with a clean slate
				kses_init_filters(); // set up the filters
			}
		}
	} else {
		wp_die( __( 'Sorry, you must be logged in to reply to a comment.' ) );
	}

	if ( '' == $comment_content )

The variable $comment_content does not seem to be defined for all execution paths leading up to this point.

		wp_die( __( 'ERROR: please type a comment.' ) );

	$comment_parent = 0;
	if ( isset( $_POST['comment_ID'] ) )
		$comment_parent = absint( $_POST['comment_ID'] );
	$comment_auto_approved = false;
	$commentdata = compact('comment_post_ID', 'comment_author', 'comment_author_email', 'comment_author_url', 'comment_content', 'comment_type', 'comment_parent', 'user_ID');

	// Automatically approve parent comment.
	if ( !empty($_POST['approve_parent']) ) {
		$parent = get_comment( $comment_parent );

		if ( $parent && $parent->comment_approved === '0' && $parent->comment_post_ID == $comment_post_ID ) {
			if ( ! current_user_can( 'edit_comment', $parent->comment_ID ) ) {
				wp_die( -1 );
			}

			if ( wp_set_comment_status( $parent, 'approve' ) )

It seems like $parent defined by get_comment($comment_parent) on line 1045 can also be of type array; however, wp_set_comment_status() does only seem to accept integer|object<WP_Comment>, maybe add an additional type check?

				$comment_auto_approved = true;
		}
	}

	$comment_id = wp_new_comment( $commentdata );
	$comment = get_comment($comment_id);
	if ( ! $comment ) wp_die( 1 );

	$position = ( isset($_POST['position']) && (int) $_POST['position'] ) ? (int) $_POST['position'] : '-1';

	ob_start();
	if ( isset( $_REQUEST['mode'] ) && 'dashboard' == $_REQUEST['mode'] ) {
		require_once( ABSPATH . 'wp-admin/includes/dashboard.php' );
		_wp_dashboard_recent_comments_row( $comment );

It seems like $comment defined by get_comment($comment_id) on line 1058 can also be of type array or null; however, _wp_dashboard_recent_comments_row() does only seem to accept object<WP_Comment>, maybe add an additional type check?

	} else {
		if ( isset( $_REQUEST['mode'] ) && 'single' == $_REQUEST['mode'] ) {
			$wp_list_table = _get_list_table('WP_Post_Comments_List_Table', array( 'screen' => 'edit-comments' ) );
		} else {
			$wp_list_table = _get_list_table('WP_Comments_List_Table', array( 'screen' => 'edit-comments' ) );
		}
		$wp_list_table->single_row( $comment );
	}
	$comment_list_item = ob_get_clean();

	$response =  array(
		'what' => 'comment',
		'id' => $comment->comment_ID,
		'data' => $comment_list_item,
		'position' => $position
	);

	$counts = wp_count_comments();
	$response['supplemental'] = array(
		'in_moderation' => $counts->moderated,
		'i18n_comments_text' => sprintf(
			_n( '%s Comment', '%s Comments', $counts->approved ),
			number_format_i18n( $counts->approved )
		),
		'i18n_moderation_text' => sprintf(
			_nx( '%s in moderation', '%s in moderation', $counts->moderated, 'comments' ),
			number_format_i18n( $counts->moderated )
		)
	);

	if ( $comment_auto_approved ) {
		$response['supplemental']['parent_approved'] = $parent->comment_ID;

The variable $parent does not seem to be defined for all execution paths leading up to this point.

		$response['supplemental']['parent_post_id'] = $parent->comment_post_ID;
	}

	$x = new WP_Ajax_Response();
	$x->add( $response );
	$x->send();
}

/**
 * Ajax handler for editing a comment.
 *
 * @since 3.1.0
 *
 * @global WP_List_Table $wp_list_table
 */
function wp_ajax_edit_comment() {
	global $wp_list_table;

	check_ajax_referer( 'replyto-comment', '_ajax_nonce-replyto-comment' );

	$comment_id = (int) $_POST['comment_ID'];
	if ( ! current_user_can( 'edit_comment', $comment_id ) )
		wp_die( -1 );

	if ( '' == $_POST['content'] )
		wp_die( __( 'ERROR: please type a comment.' ) );

	if ( isset( $_POST['status'] ) )
		$_POST['comment_status'] = $_POST['status'];
	edit_comment();

	$position = ( isset($_POST['position']) && (int) $_POST['position']) ? (int) $_POST['position'] : '-1';
	$checkbox = ( isset($_POST['checkbox']) && true == $_POST['checkbox'] ) ? 1 : 0;
	$wp_list_table = _get_list_table( $checkbox ? 'WP_Comments_List_Table' : 'WP_Post_Comments_List_Table', array( 'screen' => 'edit-comments' ) );

	$comment = get_comment( $comment_id );
	if ( empty( $comment->comment_ID ) )
		wp_die( -1 );

	ob_start();
	$wp_list_table->single_row( $comment );
	$comment_list_item = ob_get_clean();

	$x = new WP_Ajax_Response();

	$x->add( array(
		'what' => 'edit_comment',
		'id' => $comment->comment_ID,
		'data' => $comment_list_item,
		'position' => $position
	));

	$x->send();
}

/**
 * Ajax handler for adding a menu item.
 *
 * @since 3.1.0
 */
function wp_ajax_add_menu_item() {
	check_ajax_referer( 'add-menu_item', 'menu-settings-column-nonce' );

	if ( ! current_user_can( 'edit_theme_options' ) )
		wp_die( -1 );

	require_once ABSPATH . 'wp-admin/includes/nav-menu.php';

	// For performance reasons, we omit some object properties from the checklist.
	// The following is a hacky way to restore them when adding non-custom items.

	$menu_items_data = array();
	foreach ( (array) $_POST['menu-item'] as $menu_item_data ) {
		if (
			! empty( $menu_item_data['menu-item-type'] ) &&
			'custom' != $menu_item_data['menu-item-type'] &&
			! empty( $menu_item_data['menu-item-object-id'] )
		) {
			switch( $menu_item_data['menu-item-type'] ) {
				case 'post_type' :
					$_object = get_post( $menu_item_data['menu-item-object-id'] );
				break;

				case 'post_type_archive' :
					$_object = get_post_type_object( $menu_item_data['menu-item-object'] );
				break;

				case 'taxonomy' :
					$_object = get_term( $menu_item_data['menu-item-object-id'], $menu_item_data['menu-item-object'] );
				break;
			}

			$_menu_items = array_map( 'wp_setup_nav_menu_item', array( $_object ) );

The variable $_object does not seem to be defined for all execution paths leading up to this point.

			$_menu_item = reset( $_menu_items );

			// Restore the missing menu item properties
			$menu_item_data['menu-item-description'] = $_menu_item->description;
		}

		$menu_items_data[] = $menu_item_data;
	}

	$item_ids = wp_save_nav_menu_items( 0, $menu_items_data );
	if ( is_wp_error( $item_ids ) )
		wp_die( 0 );

	$menu_items = array();

	foreach ( (array) $item_ids as $menu_item_id ) {
		$menu_obj = get_post( $menu_item_id );
		if ( ! empty( $menu_obj->ID ) ) {
			$menu_obj = wp_setup_nav_menu_item( $menu_obj );

It seems like $menu_obj can also be of type array; however, wp_setup_nav_menu_item() does only seem to accept object, maybe add an additional type check?

			$menu_obj->label = $menu_obj->title; // don't show "(pending)" in ajax-added items
			$menu_items[] = $menu_obj;
		}
	}

	/** This filter is documented in wp-admin/includes/nav-menu.php */
	$walker_class_name = apply_filters( 'wp_edit_nav_menu_walker', 'Walker_Nav_Menu_Edit', $_POST['menu'] );

	if ( ! class_exists( $walker_class_name ) )
		wp_die( 0 );

	if ( ! empty( $menu_items ) ) {
		$args = array(
			'after' => '',
			'before' => '',
			'link_after' => '',
			'link_before' => '',
			'walker' => new $walker_class_name,
		);
		echo walk_nav_menu_tree( $menu_items, 0, (object) $args );
	}
	wp_die();
}

/**
 * Ajax handler for adding meta.
 *
 * @since 3.1.0
 */
function wp_ajax_add_meta() {
	check_ajax_referer( 'add-meta', '_ajax_nonce-add-meta' );
	$c = 0;
	$pid = (int) $_POST['post_id'];
	$post = get_post( $pid );

	if ( isset($_POST['metakeyselect']) || isset($_POST['metakeyinput']) ) {
		if ( !current_user_can( 'edit_post', $pid ) )
			wp_die( -1 );
		if ( isset($_POST['metakeyselect']) && '#NONE#' == $_POST['metakeyselect'] && empty($_POST['metakeyinput']) )
			wp_die( 1 );

		// If the post is an autodraft, save the post as a draft and then attempt to save the meta.
		if ( $post->post_status == 'auto-draft' ) {
			$post_data = array();
			$post_data['action'] = 'draft'; // Warning fix
			$post_data['post_ID'] = $pid;
			$post_data['post_type'] = $post->post_type;
			$post_data['post_status'] = 'draft';
			$now = current_time('timestamp', 1);
			$post_data['post_title'] = sprintf( __( 'Draft created on %1$s at %2$s' ), date( __( 'F j, Y' ), $now ), date( __( 'g:i a' ), $now ) );

			$pid = edit_post( $post_data );
			if ( $pid ) {
				if ( is_wp_error( $pid ) ) {
					$x = new WP_Ajax_Response( array(
						'what' => 'meta',
						'data' => $pid
					) );
					$x->send();
				}

				if ( !$mid = add_meta( $pid ) )
					wp_die( __( 'Please provide a custom field value.' ) );
			} else {
				wp_die( 0 );
			}
		} elseif ( ! $mid = add_meta( $pid ) ) {
			wp_die( __( 'Please provide a custom field value.' ) );
		}

		$meta = get_metadata_by_mid( 'post', $mid );

The variable $mid does not seem to be defined for all execution paths leading up to this point.

It seems like $mid can also be of type false; however, get_metadata_by_mid() does only seem to accept integer, did you maybe forget to handle an error condition?

		$pid = (int) $meta->post_id;
		$meta = get_object_vars( $meta );
		$x = new WP_Ajax_Response( array(
			'what' => 'meta',
			'id' => $mid,
			'data' => _list_meta_row( $meta, $c ),
			'position' => 1,
			'supplemental' => array('postid' => $pid)
		) );
	} else { // Update?
		$mid = (int) key( $_POST['meta'] );
		$key = wp_unslash( $_POST['meta'][$mid]['key'] );
		$value = wp_unslash( $_POST['meta'][$mid]['value'] );
		if ( '' == trim($key) )
			wp_die( __( 'Please provide a custom field name.' ) );
		if ( '' == trim($value) )
			wp_die( __( 'Please provide a custom field value.' ) );
		if ( ! $meta = get_metadata_by_mid( 'post', $mid ) )
			wp_die( 0 ); // if meta doesn't exist
		if ( is_protected_meta( $meta->meta_key, 'post' ) || is_protected_meta( $key, 'post' ) ||

It seems like $key defined by wp_unslash($_POST['meta'][$mid]['key']) on line 1293 can also be of type array; however, is_protected_meta() does only seem to accept string, maybe add an additional type check?

			! current_user_can( 'edit_post_meta', $meta->post_id, $meta->meta_key ) ||
			! current_user_can( 'edit_post_meta', $meta->post_id, $key ) )
			wp_die( -1 );
		if ( $meta->meta_value != $value || $meta->meta_key != $key ) {
			if ( !$u = update_metadata_by_mid( 'post', $mid, $value, $key ) )

It seems like $value defined by wp_unslash($_POST['meta'][$mid]['value']) on line 1294 can also be of type array; however, update_metadata_by_mid() does only seem to accept string, maybe add an additional type check?

It seems like $key defined by wp_unslash($_POST['meta'][$mid]['key']) on line 1293 can also be of type array; however, update_metadata_by_mid() does only seem to accept false|string, maybe add an additional type check?

				wp_die( 0 ); // We know meta exists; we also know it's unchanged (or DB error, in which case there are bigger problems).
		}

		$x = new WP_Ajax_Response( array(
			'what' => 'meta',
			'id' => $mid, 'old_id' => $mid,
			'data' => _list_meta_row( array(
				'meta_key' => $key,
				'meta_value' => $value,
				'meta_id' => $mid
			), $c ),
			'position' => 0,
			'supplemental' => array('postid' => $meta->post_id)
		) );
	}
	$x->send();
}

/**
 * Ajax handler for adding a user.
 *
 * @since 3.1.0
 *
 * @global WP_List_Table $wp_list_table
 *
 * @param string $action Action to perform.
 */
function wp_ajax_add_user( $action ) {
	global $wp_list_table;
	if ( empty( $action ) )
		$action = 'add-user';

	check_ajax_referer( $action );
	if ( ! current_user_can('create_users') )
		wp_die( -1 );
	if ( ! $user_id = edit_user() ) {
		wp_die( 0 );
	} elseif ( is_wp_error( $user_id ) ) {
		$x = new WP_Ajax_Response( array(
			'what' => 'user',
			'id' => $user_id
		) );
		$x->send();
	}
	$user_object = get_userdata( $user_id );

It seems like $user_id defined by edit_user() on line 1342 can also be of type object<WP_Error>; however, get_userdata() does only seem to accept integer, maybe add an additional type check?

	$wp_list_table = _get_list_table('WP_Users_List_Table');

	$role = current( $user_object->roles );

	$x = new WP_Ajax_Response( array(
		'what' => 'user',
		'id' => $user_id,
		'data' => $wp_list_table->single_row( $user_object, '', $role ),
		'supplemental' => array(
			'show-link' => sprintf(
				/* translators: %s: the new user */
				__( 'User %s added' ),
				'<a href="#user-' . $user_id . '">' . $user_object->user_login . '</a>'
			),
			'role' => $role,
		)
	) );
	$x->send();
}

/**
 * Ajax handler for closed post boxes.
 *
 * @since 3.1.0
 */
function wp_ajax_closed_postboxes() {
	check_ajax_referer( 'closedpostboxes', 'closedpostboxesnonce' );
	$closed = isset( $_POST['closed'] ) ? explode( ',', $_POST['closed']) : array();
	$closed = array_filter($closed);

	$hidden = isset( $_POST['hidden'] ) ? explode( ',', $_POST['hidden']) : array();
	$hidden = array_filter($hidden);

	$page = isset( $_POST['page'] ) ? $_POST['page'] : '';

	if ( $page != sanitize_key( $page ) )
		wp_die( 0 );

	if ( ! $user = wp_get_current_user() )
		wp_die( -1 );

	if ( is_array($closed) )
		update_user_option($user->ID, "closedpostboxes_$page", $closed, true);

	if ( is_array($hidden) ) {
		$hidden = array_diff( $hidden, array('submitdiv', 'linksubmitdiv', 'manage-menu', 'create-menu') ); // postboxes that are always shown
		update_user_option($user->ID, "metaboxhidden_$page", $hidden, true);
	}

	wp_die( 1 );
}

/**
 * Ajax handler for hidden columns.
 *
 * @since 3.1.0
 */
function wp_ajax_hidden_columns() {
	check_ajax_referer( 'screen-options-nonce', 'screenoptionnonce' );
	$page = isset( $_POST['page'] ) ? $_POST['page'] : '';

	if ( $page != sanitize_key( $page ) )
		wp_die( 0 );

	if ( ! $user = wp_get_current_user() )
		wp_die( -1 );

	$hidden = ! empty( $_POST['hidden'] ) ? explode( ',', $_POST['hidden'] ) : array();
	update_user_option( $user->ID, "manage{$page}columnshidden", $hidden, true );

	wp_die( 1 );
}

/**
 * Ajax handler for updating whether to display the welcome panel.
 *
 * @since 3.1.0
 */
function wp_ajax_update_welcome_panel() {
	check_ajax_referer( 'welcome-panel-nonce', 'welcomepanelnonce' );

	if ( ! current_user_can( 'edit_theme_options' ) )
		wp_die( -1 );

	update_user_meta( get_current_user_id(), 'show_welcome_panel', empty( $_POST['visible'] ) ? 0 : 1 );

	wp_die( 1 );
}

/**
 * Ajax handler for retrieving menu meta boxes.
 *
 * @since 3.1.0
 */
function wp_ajax_menu_get_metabox() {
	if ( ! current_user_can( 'edit_theme_options' ) )
		wp_die( -1 );

	require_once ABSPATH . 'wp-admin/includes/nav-menu.php';

	if ( isset( $_POST['item-type'] ) && 'post_type' == $_POST['item-type'] ) {
		$type = 'posttype';
		$callback = 'wp_nav_menu_item_post_type_meta_box';
		$items = (array) get_post_types( array( 'show_in_nav_menus' => true ), 'object' );
	} elseif ( isset( $_POST['item-type'] ) && 'taxonomy' == $_POST['item-type'] ) {
		$type = 'taxonomy';
		$callback = 'wp_nav_menu_item_taxonomy_meta_box';
		$items = (array) get_taxonomies( array( 'show_ui' => true ), 'object' );
	}

	if ( ! empty( $_POST['item-object'] ) && isset( $items[$_POST['item-object']] ) ) {
		$menus_meta_box_object = $items[ $_POST['item-object'] ];

		/** This filter is documented in wp-admin/includes/nav-menu.php */
		$item = apply_filters( 'nav_menu_meta_box_object', $menus_meta_box_object );
		ob_start();
		call_user_func_array($callback, array(

The variable $callback does not seem to be defined for all execution paths leading up to this point.

			null,
			array(
				'id' => 'add-' . $item->name,
				'title' => $item->labels->name,
				'callback' => $callback,
				'args' => $item,
			)
		));

		$markup = ob_get_clean();

		echo wp_json_encode(array(
			'replace-id' => $type . '-' . $item->name,

The variable $type does not seem to be defined for all execution paths leading up to this point.

			'markup' => $markup,
		));
	}

	wp_die();
}

/**
 * Ajax handler for internal linking.
 *
 * @since 3.1.0
 */
function wp_ajax_wp_link_ajax() {
	check_ajax_referer( 'internal-linking', '_ajax_linking_nonce' );

	$args = array();

	if ( isset( $_POST['search'] ) ) {
		$args['s'] = wp_unslash( $_POST['search'] );
	}

	if ( isset( $_POST['term'] ) ) {
		$args['s'] = wp_unslash( $_POST['term'] );
	}

	$args['pagenum'] = ! empty( $_POST['page'] ) ? absint( $_POST['page'] ) : 1;

	require(ABSPATH . WPINC . '/class-wp-editor.php');
	$results = _WP_Editors::wp_link_query( $args );

	if ( ! isset( $results ) )
		wp_die( 0 );

	echo wp_json_encode( $results );
	echo "\n";

	wp_die();
}

/**
 * Ajax handler for menu locations save.
 *
 * @since 3.1.0
 */
function wp_ajax_menu_locations_save() {
	if ( ! current_user_can( 'edit_theme_options' ) )
		wp_die( -1 );
	check_ajax_referer( 'add-menu_item', 'menu-settings-column-nonce' );
	if ( ! isset( $_POST['menu-locations'] ) )
		wp_die( 0 );
	set_theme_mod( 'nav_menu_locations', array_map( 'absint', $_POST['menu-locations'] ) );
	wp_die( 1 );
}

/**
 * Ajax handler for saving the meta box order.
 *
 * @since 3.1.0
 */
function wp_ajax_meta_box_order() {
	check_ajax_referer( 'meta-box-order' );
	$order = isset( $_POST['order'] ) ? (array) $_POST['order'] : false;
	$page_columns = isset( $_POST['page_columns'] ) ? $_POST['page_columns'] : 'auto';

	if ( $page_columns != 'auto' )
		$page_columns = (int) $page_columns;

	$page = isset( $_POST['page'] ) ? $_POST['page'] : '';

	if ( $page != sanitize_key( $page ) )
		wp_die( 0 );

	if ( ! $user = wp_get_current_user() )
		wp_die( -1 );

	if ( $order )
		update_user_option($user->ID, "meta-box-order_$page", $order, true);

	if ( $page_columns )
		update_user_option($user->ID, "screen_layout_$page", $page_columns, true);

	wp_die( 1 );
}

/**
 * Ajax handler for menu quick searching.
 *
 * @since 3.1.0
 */
function wp_ajax_menu_quick_search() {
	if ( ! current_user_can( 'edit_theme_options' ) )
		wp_die( -1 );

	require_once ABSPATH . 'wp-admin/includes/nav-menu.php';

	_wp_ajax_menu_quick_search( $_POST );

	wp_die();
}

/**
 * Ajax handler to retrieve a permalink.
 *
 * @since 3.1.0
 */
function wp_ajax_get_permalink() {
	check_ajax_referer( 'getpermalink', 'getpermalinknonce' );
	$post_id = isset($_POST['post_id'])? intval($_POST['post_id']) : 0;
	wp_die( get_preview_post_link( $post_id ) );
}

/**
 * Ajax handler to retrieve a sample permalink.
 *
 * @since 3.1.0
 */
function wp_ajax_sample_permalink() {
	check_ajax_referer( 'samplepermalink', 'samplepermalinknonce' );
	$post_id = isset($_POST['post_id'])? intval($_POST['post_id']) : 0;
	$title = isset($_POST['new_title'])? $_POST['new_title'] : '';
	$slug = isset($_POST['new_slug'])? $_POST['new_slug'] : null;
	wp_die( get_sample_permalink_html( $post_id, $title, $slug ) );
}

/**
 * Ajax handler for Quick Edit saving a post from a list table.
 *
 * @since 3.1.0
 *
 * @global WP_List_Table $wp_list_table
 */
function wp_ajax_inline_save() {
	global $wp_list_table, $mode;

	check_ajax_referer( 'inlineeditnonce', '_inline_edit' );

	if ( ! isset($_POST['post_ID']) || ! ( $post_ID = (int) $_POST['post_ID'] ) )
		wp_die();

	if ( 'page' == $_POST['post_type'] ) {
		if ( ! current_user_can( 'edit_page', $post_ID ) )

The variable $post_ID does not seem to be defined for all execution paths leading up to this point.

			wp_die( __( 'Sorry, you are not allowed to edit this page.' ) );
	} else {
		if ( ! current_user_can( 'edit_post', $post_ID ) )
			wp_die( __( 'Sorry, you are not allowed to edit this post.' ) );
	}

	if ( $last = wp_check_post_lock( $post_ID ) ) {
		$last_user = get_userdata( $last );
		$last_user_name = $last_user ? $last_user->display_name : __( 'Someone' );
		printf( $_POST['post_type'] == 'page' ? __( 'Saving is disabled: %s is currently editing this page.' ) : __( 'Saving is disabled: %s is currently editing this post.' ),	esc_html( $last_user_name ) );
		wp_die();
	}

	$data = &$_POST;

	$post = get_post( $post_ID, ARRAY_A );

	// Since it's coming from the database.
	$post = wp_slash($post);

It seems like $post can also be of type null or object<WP_Post>; however, wp_slash() does only seem to accept string|array, maybe add an additional type check?

	$data['content'] = $post['post_content'];
	$data['excerpt'] = $post['post_excerpt'];

	// Rename.
	$data['user_ID'] = get_current_user_id();

	if ( isset($data['post_parent']) )
		$data['parent_id'] = $data['post_parent'];

	// Status.
	if ( isset( $data['keep_private'] ) && 'private' == $data['keep_private'] ) {
		$data['visibility']  = 'private';
		$data['post_status'] = 'private';
	} else {
		$data['post_status'] = $data['_status'];
	}

	if ( empty($data['comment_status']) )
		$data['comment_status'] = 'closed';
	if ( empty($data['ping_status']) )
		$data['ping_status'] = 'closed';

	// Exclude terms from taxonomies that are not supposed to appear in Quick Edit.
	if ( ! empty( $data['tax_input'] ) ) {
		foreach ( $data['tax_input'] as $taxonomy => $terms ) {
			$tax_object = get_taxonomy( $taxonomy );
			/** This filter is documented in wp-admin/includes/class-wp-posts-list-table.php */
			if ( ! apply_filters( 'quick_edit_show_taxonomy', $tax_object->show_in_quick_edit, $taxonomy, $post['post_type'] ) ) {
				unset( $data['tax_input'][ $taxonomy ] );
			}
		}
	}

	// Hack: wp_unique_post_slug() doesn't work for drafts, so we will fake that our post is published.
	if ( ! empty( $data['post_name'] ) && in_array( $post['post_status'], array( 'draft', 'pending' ) ) ) {
		$post['post_status'] = 'publish';
		$data['post_name'] = wp_unique_post_slug( $data['post_name'], $post['ID'], $post['post_status'], $post['post_type'], $post['post_parent'] );
	}

	// Update the post.
	edit_post();

	$wp_list_table = _get_list_table( 'WP_Posts_List_Table', array( 'screen' => $_POST['screen'] ) );

	$mode = $_POST['post_view'] === 'excerpt' ? 'excerpt' : 'list';

	$level = 0;
	if ( is_post_type_hierarchical( $wp_list_table->screen->post_type ) ) {
		$request_post = array( get_post( $_POST['post_ID'] ) );
		$parent       = $request_post[0]->post_parent;

		while ( $parent > 0 ) {
			$parent_post = get_post( $parent );
			$parent      = $parent_post->post_parent;
			$level++;
		}
	}

	$wp_list_table->display_rows( array( get_post( $_POST['post_ID'] ) ), $level );

	wp_die();
}

/**
 * Ajax handler for quick edit saving for a term.
 *
 * @since 3.1.0
 *
 * @global WP_List_Table $wp_list_table
 */
function wp_ajax_inline_save_tax() {
	global $wp_list_table;

	check_ajax_referer( 'taxinlineeditnonce', '_inline_edit' );

	$taxonomy = sanitize_key( $_POST['taxonomy'] );
	$tax = get_taxonomy( $taxonomy );
	if ( ! $tax )
		wp_die( 0 );

	if ( ! current_user_can( $tax->cap->edit_terms ) )
		wp_die( -1 );

	$wp_list_table = _get_list_table( 'WP_Terms_List_Table', array( 'screen' => 'edit-' . $taxonomy ) );

	if ( ! isset($_POST['tax_ID']) || ! ( $id = (int) $_POST['tax_ID'] ) )
		wp_die( -1 );

	$tag = get_term( $id, $taxonomy );

The variable $id does not seem to be defined for all execution paths leading up to this point.

	$_POST['description'] = $tag->description;

	$updated = wp_update_term($id, $taxonomy, $_POST);
	if ( $updated && !is_wp_error($updated) ) {
		$tag = get_term( $updated['term_id'], $taxonomy );
		if ( !$tag || is_wp_error( $tag ) ) {
			if ( is_wp_error($tag) && $tag->get_error_message() )
				wp_die( $tag->get_error_message() );

The method get_error_message does only exist in WP_Error, but not in WP_Term.

			wp_die( __( 'Item not updated.' ) );
		}
	} else {
		if ( is_wp_error($updated) && $updated->get_error_message() )
			wp_die( $updated->get_error_message() );
		wp_die( __( 'Item not updated.' ) );
	}
	$level = 0;
	$parent = $tag->parent;
	while ( $parent > 0 ) {
		$parent_tag = get_term( $parent, $taxonomy );
		$parent = $parent_tag->parent;
		$level++;
	}
	$wp_list_table->single_row( $tag, $level );
	wp_die();
}

/**
 * Ajax handler for querying posts for the Find Posts modal.
 *
 * @see window.findPosts
 *
 * @since 3.1.0
 */
function wp_ajax_find_posts() {
	check_ajax_referer( 'find-posts' );

	$post_types = get_post_types( array( 'public' => true ), 'objects' );
	unset( $post_types['attachment'] );

	$s = wp_unslash( $_POST['ps'] );
	$args = array(
		'post_type' => array_keys( $post_types ),
		'post_status' => 'any',
		'posts_per_page' => 50,
	);
	if ( '' !== $s )
		$args['s'] = $s;

	$posts = get_posts( $args );

	if ( ! $posts ) {
		wp_send_json_error( __( 'No items found.' ) );
	}

	$html = '<table class="widefat"><thead><tr><th class="found-radio"><br /></th><th>'.__('Title').'</th><th class="no-break">'.__('Type').'</th><th class="no-break">'.__('Date').'</th><th class="no-break">'.__('Status').'</th></tr></thead><tbody>';
	$alt = '';
	foreach ( $posts as $post ) {
		$title = trim( $post->post_title ) ? $post->post_title : __( '(no title)' );
		$alt = ( 'alternate' == $alt ) ? '' : 'alternate';

		switch ( $post->post_status ) {
			case 'publish' :
			case 'private' :
				$stat = __('Published');
				break;
			case 'future' :
				$stat = __('Scheduled');
				break;
			case 'pending' :
				$stat = __('Pending Review');
				break;
			case 'draft' :
				$stat = __('Draft');
				break;
		}

		if ( '0000-00-00 00:00:00' == $post->post_date ) {
			$time = '';
		} else {
			/* translators: date format in table columns, see https://secure.php.net/date */
			$time = mysql2date(__('Y/m/d'), $post->post_date);
		}

		$html .= '<tr class="' . trim( 'found-posts ' . $alt ) . '"><td class="found-radio"><input type="radio" id="found-'.$post->ID.'" name="found_post_id" value="' . esc_attr($post->ID) . '"></td>';
		$html .= '<td><label for="found-'.$post->ID.'">' . esc_html( $title ) . '</label></td><td class="no-break">' . esc_html( $post_types[$post->post_type]->labels->singular_name ) . '</td><td class="no-break">'.esc_html( $time ) . '</td><td class="no-break">' . esc_html( $stat ). ' </td></tr>' . "\n\n";

The variable $stat does not seem to be defined for all execution paths leading up to this point.

	}

	$html .= '</tbody></table>';

	wp_send_json_success( $html );
}

/**
 * Ajax handler for saving the widgets order.
 *
 * @since 3.1.0
 */
function wp_ajax_widgets_order() {
	check_ajax_referer( 'save-sidebar-widgets', 'savewidgets' );

	if ( !current_user_can('edit_theme_options') )
		wp_die( -1 );

	unset( $_POST['savewidgets'], $_POST['action'] );

	// Save widgets order for all sidebars.
	if ( is_array($_POST['sidebars']) ) {
		$sidebars = array();
		foreach ( $_POST['sidebars'] as $key => $val ) {
			$sb = array();
			if ( !empty($val) ) {
				$val = explode(',', $val);
				foreach ( $val as $k => $v ) {
					if ( strpos($v, 'widget-') === false )
						continue;

					$sb[$k] = substr($v, strpos($v, '_') + 1);
				}
			}
			$sidebars[$key] = $sb;
		}
		wp_set_sidebars_widgets($sidebars);
		wp_die( 1 );
	}

	wp_die( -1 );
}

/**
 * Ajax handler for saving a widget.
 *
 * @since 3.1.0
 *
 * @global array $wp_registered_widgets
 * @global array $wp_registered_widget_controls
 * @global array $wp_registered_widget_updates
 */
function wp_ajax_save_widget() {
	global $wp_registered_widgets, $wp_registered_widget_controls, $wp_registered_widget_updates;

	check_ajax_referer( 'save-sidebar-widgets', 'savewidgets' );

	if ( !current_user_can('edit_theme_options') || !isset($_POST['id_base']) )
		wp_die( -1 );

	unset( $_POST['savewidgets'], $_POST['action'] );

	/**
	 * Fires early when editing the widgets displayed in sidebars.
	 *
	 * @since 2.8.0
	 */
	do_action( 'load-widgets.php' );

	/**
	 * Fires early when editing the widgets displayed in sidebars.
	 *
	 * @since 2.8.0
	 */
	do_action( 'widgets.php' );

	/** This action is documented in wp-admin/widgets.php */
	do_action( 'sidebar_admin_setup' );

	$id_base = $_POST['id_base'];
	$widget_id = $_POST['widget-id'];
	$sidebar_id = $_POST['sidebar'];
	$multi_number = !empty($_POST['multi_number']) ? (int) $_POST['multi_number'] : 0;
	$settings = isset($_POST['widget-' . $id_base]) && is_array($_POST['widget-' . $id_base]) ? $_POST['widget-' . $id_base] : false;
	$error = '<p>' . __('An error has occurred. Please reload the page and try again.') . '</p>';

	$sidebars = wp_get_sidebars_widgets();
	$sidebar = isset($sidebars[$sidebar_id]) ? $sidebars[$sidebar_id] : array();

	// Delete.
	if ( isset($_POST['delete_widget']) && $_POST['delete_widget'] ) {

		if ( !isset($wp_registered_widgets[$widget_id]) )
			wp_die( $error );

		$sidebar = array_diff( $sidebar, array($widget_id) );
		$_POST = array('sidebar' => $sidebar_id, 'widget-' . $id_base => array(), 'the-widget-id' => $widget_id, 'delete_widget' => '1');

		/** This action is documented in wp-admin/widgets.php */
		do_action( 'delete_widget', $widget_id, $sidebar_id, $id_base );

	} elseif ( $settings && preg_match( '/__i__|%i%/', key($settings) ) ) {
		if ( !$multi_number )
			wp_die( $error );

		$_POST[ 'widget-' . $id_base ] = array( $multi_number => reset( $settings ) );
		$widget_id = $id_base . '-' . $multi_number;
		$sidebar[] = $widget_id;
	}
	$_POST['widget-id'] = $sidebar;

	foreach ( (array) $wp_registered_widget_updates as $name => $control ) {

		if ( $name == $id_base ) {
			if ( !is_callable( $control['callback'] ) )
				continue;

			ob_start();
				call_user_func_array( $control['callback'], $control['params'] );
			ob_end_clean();
			break;
		}
	}

	if ( isset($_POST['delete_widget']) && $_POST['delete_widget'] ) {
		$sidebars[$sidebar_id] = $sidebar;
		wp_set_sidebars_widgets($sidebars);
		echo "deleted:$widget_id";
		wp_die();
	}

	if ( !empty($_POST['add_new']) )
		wp_die();

	if ( $form = $wp_registered_widget_controls[$widget_id] )
		call_user_func_array( $form['callback'], $form['params'] );

	wp_die();
}

/**
 * Ajax handler for saving a widget.
 *
 * @since 3.9.0
 *
 * @global WP_Customize_Manager $wp_customize
 */
function wp_ajax_update_widget() {
	global $wp_customize;
	$wp_customize->widgets->wp_ajax_update_widget();
}

/**
 * Ajax handler for removing inactive widgets.
 *
 * @since 4.4.0
 */
function wp_ajax_delete_inactive_widgets() {
	check_ajax_referer( 'remove-inactive-widgets', 'removeinactivewidgets' );

	if ( ! current_user_can( 'edit_theme_options' ) ) {
		wp_die( -1 );
	}

	unset( $_POST['removeinactivewidgets'], $_POST['action'] );

	do_action( 'load-widgets.php' );
	do_action( 'widgets.php' );
	do_action( 'sidebar_admin_setup' );

	$sidebars_widgets = wp_get_sidebars_widgets();

	foreach ( $sidebars_widgets['wp_inactive_widgets'] as $key => $widget_id ) {
		$pieces = explode( '-', $widget_id );
		$multi_number = array_pop( $pieces );
		$id_base = implode( '-', $pieces );
		$widget = get_option( 'widget_' . $id_base );
		unset( $widget[$multi_number] );
		update_option( 'widget_' . $id_base, $widget );
		unset( $sidebars_widgets['wp_inactive_widgets'][$key] );
	}

	wp_set_sidebars_widgets( $sidebars_widgets );

	wp_die();
}

/**
 * Ajax handler for uploading attachments
 *
 * @since 3.3.0
 */
function wp_ajax_upload_attachment() {
	check_ajax_referer( 'media-form' );
	/*
	 * This function does not use wp_send_json_success() / wp_send_json_error()
	 * as the html4 Plupload handler requires a text/html content-type for older IE.
	 * See https://core.trac.wordpress.org/ticket/31037
	 */

	if ( ! current_user_can( 'upload_files' ) ) {
		echo wp_json_encode( array(
			'success' => false,
			'data'    => array(
				'message'  => __( 'Sorry, you are not allowed to upload files.' ),
				'filename' => $_FILES['async-upload']['name'],
			)
		) );

		wp_die();
	}

	if ( isset( $_REQUEST['post_id'] ) ) {
		$post_id = $_REQUEST['post_id'];
		if ( ! current_user_can( 'edit_post', $post_id ) ) {
			echo wp_json_encode( array(
				'success' => false,
				'data'    => array(
					'message'  => __( "You don't have permission to attach files to this post." ),
					'filename' => $_FILES['async-upload']['name'],
				)
			) );

			wp_die();
		}
	} else {
		$post_id = null;
	}

	$post_data = isset( $_REQUEST['post_data'] ) ? $_REQUEST['post_data'] : array();

	// If the context is custom header or background, make sure the uploaded file is an image.
	if ( isset( $post_data['context'] ) && in_array( $post_data['context'], array( 'custom-header', 'custom-background' ) ) ) {
		$wp_filetype = wp_check_filetype_and_ext( $_FILES['async-upload']['tmp_name'], $_FILES['async-upload']['name'] );
		if ( ! wp_match_mime_types( 'image', $wp_filetype['type'] ) ) {
			echo wp_json_encode( array(
				'success' => false,
				'data'    => array(
					'message'  => __( 'The uploaded file is not a valid image. Please try again.' ),
					'filename' => $_FILES['async-upload']['name'],
				)
			) );

			wp_die();
		}
	}

	$attachment_id = media_handle_upload( 'async-upload', $post_id, $post_data );

	if ( is_wp_error( $attachment_id ) ) {
		echo wp_json_encode( array(
			'success' => false,
			'data'    => array(
				'message'  => $attachment_id->get_error_message(),
				'filename' => $_FILES['async-upload']['name'],
			)
		) );

		wp_die();
	}

	if ( isset( $post_data['context'] ) && isset( $post_data['theme'] ) ) {
		if ( 'custom-background' === $post_data['context'] )
			update_post_meta( $attachment_id, '_wp_attachment_is_custom_background', $post_data['theme'] );

It seems like $attachment_id defined by media_handle_upload('async-upload', $post_id, $post_data) on line 2065 can also be of type object<WP_Error>; however, update_post_meta() does only seem to accept integer, maybe add an additional type check?

		if ( 'custom-header' === $post_data['context'] )
			update_post_meta( $attachment_id, '_wp_attachment_is_custom_header', $post_data['theme'] );

It seems like $attachment_id defined by media_handle_upload('async-upload', $post_id, $post_data) on line 2065 can also be of type object<WP_Error>; however, update_post_meta() does only seem to accept integer, maybe add an additional type check?

	}

	if ( ! $attachment = wp_prepare_attachment_for_js( $attachment_id ) )
		wp_die();

	echo wp_json_encode( array(
		'success' => true,
		'data'    => $attachment,
	) );

	wp_die();
}

/**
 * Ajax handler for image editing.
 *
 * @since 3.1.0
 */
function wp_ajax_image_editor() {
	$attachment_id = intval($_POST['postid']);
	if ( empty($attachment_id) || !current_user_can('edit_post', $attachment_id) )
		wp_die( -1 );

	check_ajax_referer( "image_editor-$attachment_id" );
	include_once( ABSPATH . 'wp-admin/includes/image-edit.php' );

	$msg = false;
	switch ( $_POST['do'] ) {
		case 'save' :
			$msg = wp_save_image($attachment_id);
			$msg = wp_json_encode($msg);
			wp_die( $msg );

It seems like $msg defined by wp_json_encode($msg) on line 2115 can also be of type false; however, wp_die() does only seem to accept string|object<WP_Error>, did you maybe forget to handle an error condition?

			break;
		case 'scale' :
			$msg = wp_save_image($attachment_id);
			break;
		case 'restore' :
			$msg = wp_restore_image($attachment_id);
			break;
	}

	wp_image_editor($attachment_id, $msg);
	wp_die();
}

/**
 * Ajax handler for setting the featured image.
 *
 * @since 3.1.0
 */
function wp_ajax_set_post_thumbnail() {
	$json = ! empty( $_REQUEST['json'] ); // New-style request

	$post_ID = intval( $_POST['post_id'] );
	if ( ! current_user_can( 'edit_post', $post_ID ) )
		wp_die( -1 );

	$thumbnail_id = intval( $_POST['thumbnail_id'] );

	if ( $json )
		check_ajax_referer( "update-post_$post_ID" );
	else
		check_ajax_referer( "set_post_thumbnail-$post_ID" );

	if ( $thumbnail_id == '-1' ) {
		if ( delete_post_thumbnail( $post_ID ) ) {
			$return = _wp_post_thumbnail_html( null, $post_ID );
			$json ? wp_send_json_success( $return ) : wp_die( $return );
		} else {
			wp_die( 0 );
		}
	}

	if ( set_post_thumbnail( $post_ID, $thumbnail_id ) ) {
		$return = _wp_post_thumbnail_html( $thumbnail_id, $post_ID );
		$json ? wp_send_json_success( $return ) : wp_die( $return );
	}

	wp_die( 0 );
}

/**
 * Ajax handler for retrieving HTML for the featured image.
 *
 * @since 4.6.0
 */
function wp_ajax_get_post_thumbnail_html() {
	$post_ID = intval( $_POST['post_id'] );

	check_ajax_referer( "update-post_$post_ID" );

	if ( ! current_user_can( 'edit_post', $post_ID ) ) {
		wp_die( -1 );
	}

	$thumbnail_id = intval( $_POST['thumbnail_id'] );

	// For backward compatibility, -1 refers to no featured image.
	if ( -1 === $thumbnail_id ) {
		$thumbnail_id = null;
	}

	$return = _wp_post_thumbnail_html( $thumbnail_id, $post_ID );
	wp_send_json_success( $return );
}

/**
 * Ajax handler for setting the featured image for an attachment.
 *
 * @since 4.0.0
 *
 * @see set_post_thumbnail()
 */
function wp_ajax_set_attachment_thumbnail() {
	if ( empty( $_POST['urls'] ) || ! is_array( $_POST['urls'] ) ) {
		wp_send_json_error();
	}

	$thumbnail_id = (int) $_POST['thumbnail_id'];
	if ( empty( $thumbnail_id ) ) {
		wp_send_json_error();
	}

	$post_ids = array();
	// For each URL, try to find its corresponding post ID.
	foreach ( $_POST['urls'] as $url ) {
		$post_id = attachment_url_to_postid( $url );
		if ( ! empty( $post_id ) ) {
			$post_ids[] = $post_id;
		}
	}

	if ( empty( $post_ids ) ) {
		wp_send_json_error();
	}

	$success = 0;
	// For each found attachment, set its thumbnail.
	foreach ( $post_ids as $post_id ) {
		if ( ! current_user_can( 'edit_post', $post_id ) ) {
			continue;
		}

		if ( set_post_thumbnail( $post_id, $thumbnail_id ) ) {
			$success++;
		}
	}

	if ( 0 === $success ) {
		wp_send_json_error();
	} else {
		wp_send_json_success();
	}

	wp_send_json_error();
}

/**
 * Ajax handler for date formatting.
 *
 * @since 3.1.0
 */
function wp_ajax_date_format() {
	wp_die( date_i18n( sanitize_option( 'date_format', wp_unslash( $_POST['date'] ) ) ) );

It seems like wp_unslash($_POST['date']) targeting wp_unslash() can also be of type array; however, sanitize_option() does only seem to accept string, maybe add an additional type check?

}

/**
 * Ajax handler for time formatting.
 *
 * @since 3.1.0
 */
function wp_ajax_time_format() {
	wp_die( date_i18n( sanitize_option( 'time_format', wp_unslash( $_POST['date'] ) ) ) );

It seems like wp_unslash($_POST['date']) targeting wp_unslash() can also be of type array; however, sanitize_option() does only seem to accept string, maybe add an additional type check?

}

/**
 * Ajax handler for saving posts from the fullscreen editor.
 *
 * @since 3.1.0
 * @deprecated 4.3.0
 */
function wp_ajax_wp_fullscreen_save_post() {
	$post_id = isset( $_POST['post_ID'] ) ? (int) $_POST['post_ID'] : 0;

	$post = null;

	if ( $post_id )
		$post = get_post( $post_id );

	check_ajax_referer('update-post_' . $post_id, '_wpnonce');

	$post_id = edit_post();

	if ( is_wp_error( $post_id ) ) {
		wp_send_json_error();
	}

	if ( $post ) {
		$last_date = mysql2date( __( 'F j, Y' ), $post->post_modified );
		$last_time = mysql2date( __( 'g:i a' ), $post->post_modified );
	} else {
		$last_date = date_i18n( __( 'F j, Y' ) );
		$last_time = date_i18n( __( 'g:i a' ) );
	}

	if ( $last_id = get_post_meta( $post_id, '_edit_last', true ) ) {
		$last_user = get_userdata( $last_id );
		$last_edited = sprintf( __('Last edited by %1$s on %2$s at %3$s'), esc_html( $last_user->display_name ), $last_date, $last_time );
	} else {
		$last_edited = sprintf( __('Last edited on %1$s at %2$s'), $last_date, $last_time );
	}

	wp_send_json_success( array( 'last_edited' => $last_edited ) );
}

/**
 * Ajax handler for removing a post lock.
 *
 * @since 3.1.0
 */
function wp_ajax_wp_remove_post_lock() {
	if ( empty( $_POST['post_ID'] ) || empty( $_POST['active_post_lock'] ) )
		wp_die( 0 );
	$post_id = (int) $_POST['post_ID'];
	if ( ! $post = get_post( $post_id ) )
		wp_die( 0 );

	check_ajax_referer( 'update-post_' . $post_id );

	if ( ! current_user_can( 'edit_post', $post_id ) )
		wp_die( -1 );

	$active_lock = array_map( 'absint', explode( ':', $_POST['active_post_lock'] ) );
	if ( $active_lock[1] != get_current_user_id() )
		wp_die( 0 );

	/**
	 * Filters the post lock window duration.
	 *
	 * @since 3.3.0
	 *
	 * @param int $interval The interval in seconds the post lock duration
	 *                      should last, plus 5 seconds. Default 150.
	 */
	$new_lock = ( time() - apply_filters( 'wp_check_post_lock_window', 150 ) + 5 ) . ':' . $active_lock[1];
	update_post_meta( $post_id, '_edit_lock', $new_lock, implode( ':', $active_lock ) );
	wp_die( 1 );
}

/**
 * Ajax handler for dismissing a WordPress pointer.
 *
 * @since 3.1.0
 */
function wp_ajax_dismiss_wp_pointer() {
	$pointer = $_POST['pointer'];
	if ( $pointer != sanitize_key( $pointer ) )
		wp_die( 0 );

//	check_ajax_referer( 'dismiss-pointer_' . $pointer );

	$dismissed = array_filter( explode( ',', (string) get_user_meta( get_current_user_id(), 'dismissed_wp_pointers', true ) ) );

	if ( in_array( $pointer, $dismissed ) )
		wp_die( 0 );

	$dismissed[] = $pointer;
	$dismissed = implode( ',', $dismissed );

	update_user_meta( get_current_user_id(), 'dismissed_wp_pointers', $dismissed );
	wp_die( 1 );
}

/**
 * Ajax handler for getting an attachment.
 *
 * @since 3.5.0
 */
function wp_ajax_get_attachment() {
	if ( ! isset( $_REQUEST['id'] ) )
		wp_send_json_error();

	if ( ! $id = absint( $_REQUEST['id'] ) )
		wp_send_json_error();

	if ( ! $post = get_post( $id ) )
		wp_send_json_error();

	if ( 'attachment' != $post->post_type )
		wp_send_json_error();

	if ( ! current_user_can( 'upload_files' ) )
		wp_send_json_error();

	if ( ! $attachment = wp_prepare_attachment_for_js( $id ) )
		wp_send_json_error();

	wp_send_json_success( $attachment );
}

/**
 * Ajax handler for querying attachments.
 *
 * @since 3.5.0
 */
function wp_ajax_query_attachments() {
	if ( ! current_user_can( 'upload_files' ) )
		wp_send_json_error();

	$query = isset( $_REQUEST['query'] ) ? (array) $_REQUEST['query'] : array();
	$keys = array(
		's', 'order', 'orderby', 'posts_per_page', 'paged', 'post_mime_type',
		'post_parent', 'post__in', 'post__not_in', 'year', 'monthnum'
	);
	foreach ( get_taxonomies_for_attachments( 'objects' ) as $t ) {
		if ( $t->query_var && isset( $query[ $t->query_var ] ) ) {
			$keys[] = $t->query_var;
		}
	}

	$query = array_intersect_key( $query, array_flip( $keys ) );
	$query['post_type'] = 'attachment';
	if ( MEDIA_TRASH
		&& ! empty( $_REQUEST['query']['post_status'] )
		&& 'trash' === $_REQUEST['query']['post_status'] ) {
		$query['post_status'] = 'trash';
	} else {
		$query['post_status'] = 'inherit';
	}

	if ( current_user_can( get_post_type_object( 'attachment' )->cap->read_private_posts ) )
		$query['post_status'] .= ',private';

	/**
	 * Filters the arguments passed to WP_Query during an Ajax
	 * call for querying attachments.
	 *
	 * @since 3.7.0
	 *
	 * @see WP_Query::parse_query()
	 *
	 * @param array $query An array of query variables.
	 */
	$query = apply_filters( 'ajax_query_attachments_args', $query );
	$query = new WP_Query( $query );

	$posts = array_map( 'wp_prepare_attachment_for_js', $query->posts );
	$posts = array_filter( $posts );

	wp_send_json_success( $posts );
}

/**
 * Ajax handler for updating attachment attributes.
 *
 * @since 3.5.0
 */
function wp_ajax_save_attachment() {
	if ( ! isset( $_REQUEST['id'] ) || ! isset( $_REQUEST['changes'] ) )
		wp_send_json_error();

	if ( ! $id = absint( $_REQUEST['id'] ) )
		wp_send_json_error();

	check_ajax_referer( 'update-post_' . $id, 'nonce' );

	if ( ! current_user_can( 'edit_post', $id ) )
		wp_send_json_error();

	$changes = $_REQUEST['changes'];
	$post    = get_post( $id, ARRAY_A );

	if ( 'attachment' != $post['post_type'] )
		wp_send_json_error();

	if ( isset( $changes['parent'] ) )
		$post['post_parent'] = $changes['parent'];

	if ( isset( $changes['title'] ) )
		$post['post_title'] = $changes['title'];

	if ( isset( $changes['caption'] ) )
		$post['post_excerpt'] = $changes['caption'];

	if ( isset( $changes['description'] ) )
		$post['post_content'] = $changes['description'];

	if ( MEDIA_TRASH && isset( $changes['status'] ) )
		$post['post_status'] = $changes['status'];

	if ( isset( $changes['alt'] ) ) {
		$alt = wp_unslash( $changes['alt'] );
		if ( $alt != get_post_meta( $id, '_wp_attachment_image_alt', true ) ) {
			$alt = wp_strip_all_tags( $alt, true );

It seems like $alt can also be of type array; however, wp_strip_all_tags() does only seem to accept string, maybe add an additional type check?

			update_post_meta( $id, '_wp_attachment_image_alt', wp_slash( $alt ) );
		}
	}

	if ( wp_attachment_is( 'audio', $post['ID'] ) ) {
		$changed = false;
		$id3data = wp_get_attachment_metadata( $post['ID'] );
		if ( ! is_array( $id3data ) ) {
			$changed = true;
			$id3data = array();
		}
		foreach ( wp_get_attachment_id3_keys( (object) $post, 'edit' ) as $key => $label ) {
			if ( isset( $changes[ $key ] ) ) {
				$changed = true;
				$id3data[ $key ] = sanitize_text_field( wp_unslash( $changes[ $key ] ) );

It seems like wp_unslash($changes[$key]) targeting wp_unslash() can also be of type array; however, sanitize_text_field() does only seem to accept string, maybe add an additional type check?

			}
		}

		if ( $changed ) {
			wp_update_attachment_metadata( $id, $id3data );
		}
	}

	if ( MEDIA_TRASH && isset( $changes['status'] ) && 'trash' === $changes['status'] ) {
		wp_delete_post( $id );
	} else {
		wp_update_post( $post );
	}

	wp_send_json_success();
}

/**
 * Ajax handler for saving backward compatible attachment attributes.
 *
 * @since 3.5.0
 */
function wp_ajax_save_attachment_compat() {
	if ( ! isset( $_REQUEST['id'] ) )
		wp_send_json_error();

	if ( ! $id = absint( $_REQUEST['id'] ) )
		wp_send_json_error();

	if ( empty( $_REQUEST['attachments'] ) || empty( $_REQUEST['attachments'][ $id ] ) )
		wp_send_json_error();
	$attachment_data = $_REQUEST['attachments'][ $id ];

	check_ajax_referer( 'update-post_' . $id, 'nonce' );

	if ( ! current_user_can( 'edit_post', $id ) )
		wp_send_json_error();

	$post = get_post( $id, ARRAY_A );

	if ( 'attachment' != $post['post_type'] )
		wp_send_json_error();

	/** This filter is documented in wp-admin/includes/media.php */
	$post = apply_filters( 'attachment_fields_to_save', $post, $attachment_data );

	if ( isset( $post['errors'] ) ) {
		$errors = $post['errors']; // @todo return me and display me!

$errors is not used, you could remove the assignment.

		unset( $post['errors'] );
	}

	wp_update_post( $post );

	foreach ( get_attachment_taxonomies( $post ) as $taxonomy ) {
		if ( isset( $attachment_data[ $taxonomy ] ) )
			wp_set_object_terms( $id, array_map( 'trim', preg_split( '/,+/', $attachment_data[ $taxonomy ] ) ), $taxonomy, false );
	}

	if ( ! $attachment = wp_prepare_attachment_for_js( $id ) )
		wp_send_json_error();

	wp_send_json_success( $attachment );
}

/**
 * Ajax handler for saving the attachment order.
 *
 * @since 3.5.0
 */
function wp_ajax_save_attachment_order() {
	if ( ! isset( $_REQUEST['post_id'] ) )
		wp_send_json_error();

	if ( ! $post_id = absint( $_REQUEST['post_id'] ) )
		wp_send_json_error();

	if ( empty( $_REQUEST['attachments'] ) )
		wp_send_json_error();

	check_ajax_referer( 'update-post_' . $post_id, 'nonce' );

	$attachments = $_REQUEST['attachments'];

	if ( ! current_user_can( 'edit_post', $post_id ) )
		wp_send_json_error();

	foreach ( $attachments as $attachment_id => $menu_order ) {
		if ( ! current_user_can( 'edit_post', $attachment_id ) )
			continue;
		if ( ! $attachment = get_post( $attachment_id ) )
			continue;
		if ( 'attachment' != $attachment->post_type )
			continue;

		wp_update_post( array( 'ID' => $attachment_id, 'menu_order' => $menu_order ) );
	}

	wp_send_json_success();
}

/**
 * Ajax handler for sending an attachment to the editor.
 *
 * Generates the HTML to send an attachment to the editor.
 * Backward compatible with the {@see 'media_send_to_editor'} filter
 * and the chain of filters that follow.
 *
 * @since 3.5.0
 */
function wp_ajax_send_attachment_to_editor() {
	check_ajax_referer( 'media-send-to-editor', 'nonce' );

	$attachment = wp_unslash( $_POST['attachment'] );

	$id = intval( $attachment['id'] );

	if ( ! $post = get_post( $id ) )
		wp_send_json_error();

	if ( 'attachment' != $post->post_type )
		wp_send_json_error();

	if ( current_user_can( 'edit_post', $id ) ) {
		// If this attachment is unattached, attach it. Primarily a back compat thing.
		if ( 0 == $post->post_parent && $insert_into_post_id = intval( $_POST['post_id'] ) ) {
			wp_update_post( array( 'ID' => $id, 'post_parent' => $insert_into_post_id ) );
		}
	}

	$url = empty( $attachment['url'] ) ? '' : $attachment['url'];
	$rel = ( strpos( $url, 'attachment_id') || get_attachment_link( $id ) == $url );

	remove_filter( 'media_send_to_editor', 'image_media_send_to_editor' );

	if ( 'image' === substr( $post->post_mime_type, 0, 5 ) ) {
		$align = isset( $attachment['align'] ) ? $attachment['align'] : 'none';
		$size = isset( $attachment['image-size'] ) ? $attachment['image-size'] : 'medium';
		$alt = isset( $attachment['image_alt'] ) ? $attachment['image_alt'] : '';

		// No whitespace-only captions.
		$caption = isset( $attachment['post_excerpt'] ) ? $attachment['post_excerpt'] : '';
		if ( '' === trim( $caption ) ) {
			$caption = '';
		}

		$title = ''; // We no longer insert title tags into <img> tags, as they are redundant.
		$html = get_image_send_to_editor( $id, $caption, $title, $align, $url, $rel, $size, $alt );
	} elseif ( wp_attachment_is( 'video', $post ) || wp_attachment_is( 'audio', $post )  ) {

It seems like $post defined by get_post($id) on line 2610 can also be of type array; however, wp_attachment_is() does only seem to accept integer|object<WP_Post>|null, maybe add an additional type check?

		$html = stripslashes_deep( $_POST['html'] );
	} else {
		$html = isset( $attachment['post_title'] ) ? $attachment['post_title'] : '';
		$rel = $rel ? ' rel="attachment wp-att-' . $id . '"' : ''; // Hard-coded string, $id is already sanitized

		if ( ! empty( $url ) ) {
			$html = '<a href="' . esc_url( $url ) . '"' . $rel . '>' . $html . '</a>';
		}
	}

	/** This filter is documented in wp-admin/includes/media.php */
	$html = apply_filters( 'media_send_to_editor', $html, $id, $attachment );

	wp_send_json_success( $html );
}

/**
 * Ajax handler for sending a link to the editor.
 *
 * Generates the HTML to send a non-image embed link to the editor.
 *
 * Backward compatible with the following filters:
 * - file_send_to_editor_url
 * - audio_send_to_editor_url
 * - video_send_to_editor_url
 *
 * @since 3.5.0
 *
 * @global WP_Post  $post
 * @global WP_Embed $wp_embed
 */
function wp_ajax_send_link_to_editor() {
	global $post, $wp_embed;

	check_ajax_referer( 'media-send-to-editor', 'nonce' );

	if ( ! $src = wp_unslash( $_POST['src'] ) )
		wp_send_json_error();

	if ( ! strpos( $src, '://' ) )
		$src = 'http://' . $src;

	if ( ! $src = esc_url_raw( $src ) )

It seems like $src can also be of type array; however, esc_url_raw() does only seem to accept string, maybe add an additional type check?

		wp_send_json_error();

	if ( ! $link_text = trim( wp_unslash( $_POST['link_text'] ) ) )
		$link_text = wp_basename( $src );

	$post = get_post( isset( $_POST['post_id'] ) ? $_POST['post_id'] : 0 );

	// Ping WordPress for an embed.
	$check_embed = $wp_embed->run_shortcode( '[embed]'. $src .'[/embed]' );

	// Fallback that WordPress creates when no oEmbed was found.
	$fallback = $wp_embed->maybe_make_link( $src );

	if ( $check_embed !== $fallback ) {
		// TinyMCE view for [embed] will parse this
		$html = '[embed]' . $src . '[/embed]';
	} elseif ( $link_text ) {
		$html = '<a href="' . esc_url( $src ) . '">' . $link_text . '</a>';
	} else {
		$html = '';
	}

	// Figure out what filter to run:
	$type = 'file';
	if ( ( $ext = preg_replace( '/^.+?\.([^.]+)$/', '$1', $src ) ) && ( $ext_type = wp_ext2type( $ext ) )
		&& ( 'audio' == $ext_type || 'video' == $ext_type ) )
			$type = $ext_type;

	/** This filter is documented in wp-admin/includes/media.php */
	$html = apply_filters( $type . '_send_to_editor_url', $html, $src, $link_text );

	wp_send_json_success( $html );
}

/**
 * Ajax handler for the Heartbeat API.
 *
 * Runs when the user is logged in.
 *
 * @since 3.6.0
 */
function wp_ajax_heartbeat() {
	if ( empty( $_POST['_nonce'] ) ) {
		wp_send_json_error();
	}

	$response = $data = array();
	$nonce_state = wp_verify_nonce( $_POST['_nonce'], 'heartbeat-nonce' );

	// screen_id is the same as $current_screen->id and the JS global 'pagenow'.
	if ( ! empty( $_POST['screen_id'] ) ) {
		$screen_id = sanitize_key($_POST['screen_id']);
	} else {
		$screen_id = 'front';
	}

	if ( ! empty( $_POST['data'] ) ) {
		$data = wp_unslash( (array) $_POST['data'] );
	}

	if ( 1 !== $nonce_state ) {
		$response = apply_filters( 'wp_refresh_nonces', $response, $data, $screen_id );

		if ( false === $nonce_state ) {
			// User is logged in but nonces have expired.
			$response['nonces_expired'] = true;
			wp_send_json( $response );
		}
	}

	if ( ! empty( $data ) ) {
		/**
		 * Filters the Heartbeat response received.
		 *
		 * @since 3.6.0
		 *
		 * @param array  $response  The Heartbeat response.
		 * @param array  $data      The $_POST data sent.
		 * @param string $screen_id The screen id.
		 */
		$response = apply_filters( 'heartbeat_received', $response, $data, $screen_id );
	}

	/**
	 * Filters the Heartbeat response sent.
	 *
	 * @since 3.6.0
	 *
	 * @param array  $response  The Heartbeat response.
	 * @param string $screen_id The screen id.
	 */
	$response = apply_filters( 'heartbeat_send', $response, $screen_id );

	/**
	 * Fires when Heartbeat ticks in logged-in environments.
	 *
	 * Allows the transport to be easily replaced with long-polling.
	 *
	 * @since 3.6.0
	 *
	 * @param array  $response  The Heartbeat response.
	 * @param string $screen_id The screen id.
	 */
	do_action( 'heartbeat_tick', $response, $screen_id );

	// Send the current time according to the server
	$response['server_time'] = time();

	wp_send_json( $response );
}

/**
 * Ajax handler for getting revision diffs.
 *
 * @since 3.6.0
 */
function wp_ajax_get_revision_diffs() {
	require ABSPATH . 'wp-admin/includes/revision.php';

	if ( ! $post = get_post( (int) $_REQUEST['post_id'] ) )
		wp_send_json_error();

	if ( ! current_user_can( 'edit_post', $post->ID ) )
		wp_send_json_error();

	// Really just pre-loading the cache here.
	if ( ! $revisions = wp_get_post_revisions( $post->ID, array( 'check_enabled' => false ) ) )
		wp_send_json_error();

	$return = array();
	@set_time_limit( 0 );

	foreach ( $_REQUEST['compare'] as $compare_key ) {
		list( $compare_from, $compare_to ) = explode( ':', $compare_key ); // from:to

		$return[] = array(
			'id' => $compare_key,
			'fields' => wp_get_revision_ui_diff( $post, $compare_from, $compare_to ),

It seems like $post defined by get_post((int) $_REQUEST['post_id']) on line 2804 can also be of type array; however, wp_get_revision_ui_diff() does only seem to accept object|integer, maybe add an additional type check?

		);
	}
	wp_send_json_success( $return );
}

/**
 * Ajax handler for auto-saving the selected color scheme for
 * a user's own profile.
 *
 * @since 3.8.0
 *
 * @global array $_wp_admin_css_colors
 */
function wp_ajax_save_user_color_scheme() {
	global $_wp_admin_css_colors;

	check_ajax_referer( 'save-color-scheme', 'nonce' );

	$color_scheme = sanitize_key( $_POST['color_scheme'] );

	if ( ! isset( $_wp_admin_css_colors[ $color_scheme ] ) ) {
		wp_send_json_error();
	}

	$previous_color_scheme = get_user_meta( get_current_user_id(), 'admin_color', true );
	update_user_meta( get_current_user_id(), 'admin_color', $color_scheme );

	wp_send_json_success( array(
		'previousScheme' => 'admin-color-' . $previous_color_scheme,
		'currentScheme'  => 'admin-color-' . $color_scheme
	) );
}

/**
 * Ajax handler for getting themes from themes_api().
 *
 * @since 3.9.0
 *
 * @global array $themes_allowedtags
 * @global array $theme_field_defaults
 */
function wp_ajax_query_themes() {
	global $themes_allowedtags, $theme_field_defaults;

	if ( ! current_user_can( 'install_themes' ) ) {
		wp_send_json_error();
	}

	$args = wp_parse_args( wp_unslash( $_REQUEST['request'] ), array(
		'per_page' => 20,
		'fields'   => $theme_field_defaults
	) );

	if ( isset( $args['browse'] ) && 'favorites' === $args['browse'] && ! isset( $args['user'] ) ) {
		$user = get_user_option( 'wporg_favorites' );
		if ( $user ) {
			$args['user'] = $user;
		}
	}

	$old_filter = isset( $args['browse'] ) ? $args['browse'] : 'search';

	/** This filter is documented in wp-admin/includes/class-wp-theme-install-list-table.php */
	$args = apply_filters( 'install_themes_table_api_args_' . $old_filter, $args );

	$api = themes_api( 'query_themes', $args );

	if ( is_wp_error( $api ) ) {
		wp_send_json_error();
	}

	$update_php = network_admin_url( 'update.php?action=install-theme' );
	foreach ( $api->themes as &$theme ) {
		$theme->install_url = add_query_arg( array(
			'theme'    => $theme->slug,
			'_wpnonce' => wp_create_nonce( 'install-theme_' . $theme->slug )
		), $update_php );

		if ( current_user_can( 'switch_themes' ) ) {
			if ( is_multisite() ) {
				$theme->activate_url = add_query_arg( array(
					'action'   => 'enable',
					'_wpnonce' => wp_create_nonce( 'enable-theme_' . $theme->slug ),
					'theme'    => $theme->slug,
				), network_admin_url( 'themes.php' ) );
			} else {
				$theme->activate_url = add_query_arg( array(
					'action'     => 'activate',
					'_wpnonce'   => wp_create_nonce( 'switch-theme_' . $theme->slug ),
					'stylesheet' => $theme->slug,
				), admin_url( 'themes.php' ) );
			}
		}

		if ( ! is_multisite() && current_user_can( 'edit_theme_options' ) && current_user_can( 'customize' ) ) {
			$theme->customize_url = add_query_arg( array(
				'return' => urlencode( network_admin_url( 'theme-install.php', 'relative' ) ),
			), wp_customize_url( $theme->slug ) );
		}

		$theme->name        = wp_kses( $theme->name, $themes_allowedtags );
		$theme->author      = wp_kses( $theme->author, $themes_allowedtags );
		$theme->version     = wp_kses( $theme->version, $themes_allowedtags );
		$theme->description = wp_kses( $theme->description, $themes_allowedtags );
		$theme->stars       = wp_star_rating( array( 'rating' => $theme->rating, 'type' => 'percent', 'number' => $theme->num_ratings, 'echo' => false ) );
		$theme->num_ratings = number_format_i18n( $theme->num_ratings );
		$theme->preview_url = set_url_scheme( $theme->preview_url );
	}

	wp_send_json_success( $api );
}

/**
 * Apply [embed] Ajax handlers to a string.
 *
 * @since 4.0.0
 *
 * @global WP_Post    $post       Global $post.
 * @global WP_Embed   $wp_embed   Embed API instance.
 * @global WP_Scripts $wp_scripts
 */
function wp_ajax_parse_embed() {
	global $post, $wp_embed;

	if ( ! $post = get_post( (int) $_POST['post_ID'] ) ) {
		wp_send_json_error();
	}

	if ( empty( $_POST['shortcode'] ) || ! current_user_can( 'edit_post', $post->ID ) ) {
		wp_send_json_error();
	}

	$shortcode = wp_unslash( $_POST['shortcode'] );

	preg_match( '/' . get_shortcode_regex() . '/s', $shortcode, $matches );
	$atts = shortcode_parse_atts( $matches[3] );
	if ( ! empty( $matches[5] ) ) {
		$url = $matches[5];
	} elseif ( ! empty( $atts['src'] ) ) {
		$url = $atts['src'];
	} else {
		$url = '';
	}

	$parsed = false;
	setup_postdata( $post );

It seems like $post defined by get_post((int) $_POST['post_ID']) on line 2947 can also be of type array or null; however, setup_postdata() does only seem to accept object|integer, maybe add an additional type check?

	$wp_embed->return_false_on_fail = true;

	if ( is_ssl() && 0 === strpos( $url, 'http://' ) ) {
		// Admin is ssl and the user pasted non-ssl URL.
		// Check if the provider supports ssl embeds and use that for the preview.
		$ssl_shortcode = preg_replace( '%^(\\[embed[^\\]]*\\])http://%i', '$1https://', $shortcode );
		$parsed = $wp_embed->run_shortcode( $ssl_shortcode );

		if ( ! $parsed ) {
			$no_ssl_support = true;
		}
	}

	if ( $url && ! $parsed ) {
		$parsed = $wp_embed->run_shortcode( $shortcode );
	}

	if ( ! $parsed ) {
		wp_send_json_error( array(
			'type' => 'not-embeddable',
			'message' => sprintf( __( '%s failed to embed.' ), '<code>' . esc_html( $url ) . '</code>' ),
		) );
	}

	if ( has_shortcode( $parsed, 'audio' ) || has_shortcode( $parsed, 'video' ) ) {
		$styles = '';
		$mce_styles = wpview_media_sandbox_styles();
		foreach ( $mce_styles as $style ) {
			$styles .= sprintf( '<link rel="stylesheet" href="%s"/>', $style );
		}

		$html = do_shortcode( $parsed );

		global $wp_scripts;
		if ( ! empty( $wp_scripts ) ) {
			$wp_scripts->done = array();
		}
		ob_start();
		wp_print_scripts( 'wp-mediaelement' );
		$scripts = ob_get_clean();

		$parsed = $styles . $html . $scripts;
	}


	if ( ! empty( $no_ssl_support ) || ( is_ssl() && ( preg_match( '%<(iframe|script|embed) [^>]*src="http://%', $parsed ) ||
		preg_match( '%<link [^>]*href="http://%', $parsed ) ) ) ) {
		// Admin is ssl and the embed is not. Iframes, scripts, and other "active content" will be blocked.
		wp_send_json_error( array(
			'type' => 'not-ssl',
			'message' => __( 'This preview is unavailable in the editor.' ),
		) );
	}

	wp_send_json_success( array(
		'body' => $parsed,
		'attr' => $wp_embed->last_attr
	) );
}

/**
 * @since 4.0.0
 *
 * @global WP_Post    $post
 * @global WP_Scripts $wp_scripts
 */
function wp_ajax_parse_media_shortcode() {
	global $post, $wp_scripts;

	if ( empty( $_POST['shortcode'] ) ) {
		wp_send_json_error();
	}

	$shortcode = wp_unslash( $_POST['shortcode'] );

	if ( ! empty( $_POST['post_ID'] ) ) {
		$post = get_post( (int) $_POST['post_ID'] );
	}

	// the embed shortcode requires a post
	if ( ! $post || ! current_user_can( 'edit_post', $post->ID ) ) {
		if ( 'embed' === $shortcode ) {
			wp_send_json_error();
		}
	} else {
		setup_postdata( $post );

It seems like $post defined by get_post((int) $_POST['post_ID']) on line 3046 can also be of type array; however, setup_postdata() does only seem to accept object|integer, maybe add an additional type check?

	}

	$parsed = do_shortcode( $shortcode  );

It seems like $shortcode defined by wp_unslash($_POST['shortcode']) on line 3043 can also be of type array; however, do_shortcode() does only seem to accept string, maybe add an additional type check?

	if ( empty( $parsed ) ) {
		wp_send_json_error( array(
			'type' => 'no-items',
			'message' => __( 'No items found.' ),
		) );
	}

	$head = '';
	$styles = wpview_media_sandbox_styles();

	foreach ( $styles as $style ) {
		$head .= '<link type="text/css" rel="stylesheet" href="' . $style . '">';
	}

	if ( ! empty( $wp_scripts ) ) {
		$wp_scripts->done = array();
	}

	ob_start();

	echo $parsed;

	if ( 'playlist' === $_REQUEST['type'] ) {
		wp_underscore_playlist_templates();

		wp_print_scripts( 'wp-playlist' );
	} else {
		wp_print_scripts( array( 'froogaloop', 'wp-mediaelement' ) );
	}

	wp_send_json_success( array(
		'head' => $head,
		'body' => ob_get_clean()
	) );
}

/**
 * Ajax handler for destroying multiple open sessions for a user.
 *
 * @since 4.1.0
 */
function wp_ajax_destroy_sessions() {
	$user = get_userdata( (int) $_POST['user_id'] );
	if ( $user ) {
		if ( ! current_user_can( 'edit_user', $user->ID ) ) {
			$user = false;
		} elseif ( ! wp_verify_nonce( $_POST['nonce'], 'update-user_' . $user->ID ) ) {
			$user = false;
		}
	}

	if ( ! $user ) {
		wp_send_json_error( array(
			'message' => __( 'Could not log out user sessions. Please try again.' ),
		) );
	}

	$sessions = WP_Session_Tokens::get_instance( $user->ID );

	if ( $user->ID === get_current_user_id() ) {
		$sessions->destroy_others( wp_get_session_token() );
		$message = __( 'You are now logged out everywhere else.' );
	} else {
		$sessions->destroy_all();
		/* translators: 1: User's display name. */
		$message = sprintf( __( '%s has been logged out.' ), $user->display_name );
	}

	wp_send_json_success( array( 'message' => $message ) );
}

/**
 * Ajax handler for saving a post from Press This.
 *
 * @since 4.2.0
 *
 * @global WP_Press_This $wp_press_this
 */
function wp_ajax_press_this_save_post() {
	if ( empty( $GLOBALS['wp_press_this'] ) ) {
		include( ABSPATH . 'wp-admin/includes/class-wp-press-this.php' );
	}

	$GLOBALS['wp_press_this']->save_post();
}

/**
 * Ajax handler for creating new category from Press This.
 *
 * @since 4.2.0
 *
 * @global WP_Press_This $wp_press_this
 */
function wp_ajax_press_this_add_category() {
	if ( empty( $GLOBALS['wp_press_this'] ) ) {
		include( ABSPATH . 'wp-admin/includes/class-wp-press-this.php' );
	}

	$GLOBALS['wp_press_this']->add_category();
}

/**
 * Ajax handler for cropping an image.
 *
 * @since 4.3.0
 *
 * @global WP_Site_Icon $wp_site_icon
 */
function wp_ajax_crop_image() {
	$attachment_id = absint( $_POST['id'] );

	check_ajax_referer( 'image_editor-' . $attachment_id, 'nonce' );
	if ( ! current_user_can( 'customize' ) ) {
		wp_send_json_error();
	}

	$context = str_replace( '_', '-', $_POST['context'] );
	$data    = array_map( 'absint', $_POST['cropDetails'] );
	$cropped = wp_crop_image( $attachment_id, $data['x1'], $data['y1'], $data['width'], $data['height'], $data['dst_width'], $data['dst_height'] );

	if ( ! $cropped || is_wp_error( $cropped ) ) {
		wp_send_json_error( array( 'message' => __( 'Image could not be processed.' ) ) );
	}

	switch ( $context ) {
		case 'site-icon':
			require_once ABSPATH . '/wp-admin/includes/class-wp-site-icon.php';
			global $wp_site_icon;

			// Skip creating a new attachment if the attachment is a Site Icon.
			if ( get_post_meta( $attachment_id, '_wp_attachment_context', true ) == $context ) {

				// Delete the temporary cropped file, we don't need it.
				wp_delete_file( $cropped );

It seems like $cropped defined by wp_crop_image($attachment_id, $data['x1'], $data['y1'], $data['width'], $data['height'], $data['dst_width'], $data['dst_height']) on line 3178 can also be of type object<WP_Error>; however, wp_delete_file() does only seem to accept string, maybe add an additional type check?

				// Additional sizes in wp_prepare_attachment_for_js().
				add_filter( 'image_size_names_choose', array( $wp_site_icon, 'additional_sizes' ) );
				break;
			}

			/** This filter is documented in wp-admin/custom-header.php */
			$cropped = apply_filters( 'wp_create_file_in_uploads', $cropped, $attachment_id ); // For replication.
			$object  = $wp_site_icon->create_attachment_object( $cropped, $attachment_id );
			unset( $object['ID'] );

			// Update the attachment.
			add_filter( 'intermediate_image_sizes_advanced', array( $wp_site_icon, 'additional_sizes' ) );
			$attachment_id = $wp_site_icon->insert_attachment( $object, $cropped );
			remove_filter( 'intermediate_image_sizes_advanced', array( $wp_site_icon, 'additional_sizes' ) );

			// Additional sizes in wp_prepare_attachment_for_js().
			add_filter( 'image_size_names_choose', array( $wp_site_icon, 'additional_sizes' ) );
			break;

		default:

			/**
			 * Fires before a cropped image is saved.
			 *
			 * Allows to add filters to modify the way a cropped image is saved.
			 *
			 * @since 4.3.0
			 *
			 * @param string $context       The Customizer control requesting the cropped image.
			 * @param int    $attachment_id The attachment ID of the original image.
			 * @param string $cropped       Path to the cropped image file.
			 */
			do_action( 'wp_ajax_crop_image_pre_save', $context, $attachment_id, $cropped );

			/** This filter is documented in wp-admin/custom-header.php */
			$cropped = apply_filters( 'wp_create_file_in_uploads', $cropped, $attachment_id ); // For replication.

			$parent_url = wp_get_attachment_url( $attachment_id );
			$url        = str_replace( basename( $parent_url ), basename( $cropped ), $parent_url );

			$size       = @getimagesize( $cropped );
			$image_type = ( $size ) ? $size['mime'] : 'image/jpeg';

			$object = array(
				'post_title'     => basename( $cropped ),
				'post_content'   => $url,
				'post_mime_type' => $image_type,
				'guid'           => $url,
				'context'        => $context,
			);

			$attachment_id = wp_insert_attachment( $object, $cropped );
			$metadata = wp_generate_attachment_metadata( $attachment_id, $cropped );

			/**
			 * Filters the cropped image attachment metadata.
			 *
			 * @since 4.3.0
			 *
			 * @see wp_generate_attachment_metadata()
			 *
			 * @param array $metadata Attachment metadata.
			 */
			$metadata = apply_filters( 'wp_ajax_cropped_attachment_metadata', $metadata );
			wp_update_attachment_metadata( $attachment_id, $metadata );

It seems like $attachment_id defined by wp_insert_attachment($object, $cropped) on line 3246 can also be of type object<WP_Error>; however, wp_update_attachment_metadata() does only seem to accept integer, maybe add an additional type check?

			/**
			 * Filters the attachment ID for a cropped image.
			 *
			 * @since 4.3.0
			 *
			 * @param int    $attachment_id The attachment ID of the cropped image.
			 * @param string $context       The Customizer control requesting the cropped image.
			 */
			$attachment_id = apply_filters( 'wp_ajax_cropped_attachment_id', $attachment_id, $context );
	}

	wp_send_json_success( wp_prepare_attachment_for_js( $attachment_id ) );
}

/**
 * Ajax handler for generating a password.
 *
 * @since 4.4.0
 */
function wp_ajax_generate_password() {
	wp_send_json_success( wp_generate_password( 24 ) );
}

/**
 * Ajax handler for saving the user's WordPress.org username.
 *
 * @since 4.4.0
 */
function wp_ajax_save_wporg_username() {
	if ( ! current_user_can( 'install_themes' ) && ! current_user_can( 'install_plugins' ) ) {
		wp_send_json_error();
	}

	check_ajax_referer( 'save_wporg_username_' . get_current_user_id() );

	$username = isset( $_REQUEST['username'] ) ? wp_unslash( $_REQUEST['username'] ) : false;

	if ( ! $username ) {
		wp_send_json_error();
	}

	wp_send_json_success( update_user_meta( get_current_user_id(), 'wporg_favorites', $username ) );
}

/**
 * Ajax handler for installing a theme.
 *
 * @since 4.6.0
 *
 * @see Theme_Upgrader
 */
function wp_ajax_install_theme() {
	check_ajax_referer( 'updates' );

	if ( empty( $_POST['slug'] ) ) {
		wp_send_json_error( array(
			'slug'         => '',
			'errorCode'    => 'no_theme_specified',
			'errorMessage' => __( 'No theme specified.' ),
		) );
	}

	$slug = sanitize_key( wp_unslash( $_POST['slug'] ) );

It seems like wp_unslash($_POST['slug']) targeting wp_unslash() can also be of type array; however, sanitize_key() does only seem to accept string, maybe add an additional type check?

	$status = array(
		'install' => 'theme',
		'slug'    => $slug,
	);

	if ( ! current_user_can( 'install_themes' ) ) {
		$status['errorMessage'] = __( 'Sorry, you are not allowed to install themes on this site.' );
		wp_send_json_error( $status );
	}

	include_once( ABSPATH . 'wp-admin/includes/class-wp-upgrader.php' );
	include_once( ABSPATH . 'wp-admin/includes/theme.php' );

	$api = themes_api( 'theme_information', array(
		'slug'   => $slug,
		'fields' => array( 'sections' => false ),
	) );

	if ( is_wp_error( $api ) ) {
		$status['errorMessage'] = $api->get_error_message();
		wp_send_json_error( $status );
	}

	$skin     = new WP_Ajax_Upgrader_Skin();
	$upgrader = new Theme_Upgrader( $skin );
	$result   = $upgrader->install( $api->download_link );

	if ( defined( 'WP_DEBUG' ) && WP_DEBUG ) {
		$status['debug'] = $skin->get_upgrade_messages();
	}

	if ( is_wp_error( $result ) ) {
		$status['errorCode']    = $result->get_error_code();
		$status['errorMessage'] = $result->get_error_message();
		wp_send_json_error( $status );
	} elseif ( is_wp_error( $skin->result ) ) {
		$status['errorCode']    = $skin->result->get_error_code();
		$status['errorMessage'] = $skin->result->get_error_message();
		wp_send_json_error( $status );
	} elseif ( $skin->get_errors()->get_error_code() ) {
		$status['errorMessage'] = $skin->get_error_messages();
		wp_send_json_error( $status );
	} elseif ( is_null( $result ) ) {
		global $wp_filesystem;

		$status['errorCode']    = 'unable_to_connect_to_filesystem';
		$status['errorMessage'] = __( 'Unable to connect to the filesystem. Please confirm your credentials.' );

		// Pass through the error from WP_Filesystem if one was raised.
		if ( $wp_filesystem instanceof WP_Filesystem_Base && is_wp_error( $wp_filesystem->errors ) && $wp_filesystem->errors->get_error_code() ) {
			$status['errorMessage'] = esc_html( $wp_filesystem->errors->get_error_message() );
		}

		wp_send_json_error( $status );
	}

	$status['themeName'] = wp_get_theme( $slug )->get( 'Name' );

	if ( current_user_can( 'switch_themes' ) ) {
		if ( is_multisite() ) {
			$status['activateUrl'] = add_query_arg( array(
				'action'   => 'enable',
				'_wpnonce' => wp_create_nonce( 'enable-theme_' . $slug ),
				'theme'    => $slug,
			), network_admin_url( 'themes.php' ) );
		} else {
			$status['activateUrl'] = add_query_arg( array(
				'action'     => 'activate',
				'_wpnonce'   => wp_create_nonce( 'switch-theme_' . $slug ),
				'stylesheet' => $slug,
			), admin_url( 'themes.php' ) );
		}
	}

	if ( ! is_multisite() && current_user_can( 'edit_theme_options' ) && current_user_can( 'customize' ) ) {
		$status['customizeUrl'] = add_query_arg( array(
			'return' => urlencode( network_admin_url( 'theme-install.php', 'relative' ) ),
		), wp_customize_url( $slug ) );
	}

	/*
	 * See WP_Theme_Install_List_Table::_get_theme_status() if we wanted to check
	 * on post-install status.
	 */
	wp_send_json_success( $status );
}

/**
 * Ajax handler for updating a theme.
 *
 * @since 4.6.0
 *
 * @see Theme_Upgrader
 */
function wp_ajax_update_theme() {
	check_ajax_referer( 'updates' );

	if ( empty( $_POST['slug'] ) ) {
		wp_send_json_error( array(
			'slug'         => '',
			'errorCode'    => 'no_theme_specified',
			'errorMessage' => __( 'No theme specified.' ),
		) );
	}

	$stylesheet = sanitize_key( wp_unslash( $_POST['slug'] ) );

It seems like wp_unslash($_POST['slug']) targeting wp_unslash() can also be of type array; however, sanitize_key() does only seem to accept string, maybe add an additional type check?

	$status     = array(
		'update'     => 'theme',
		'slug'       => $stylesheet,
		'newVersion' => '',
	);

	if ( ! current_user_can( 'update_themes' ) ) {
		$status['errorMessage'] = __( 'Sorry, you are not allowed to update themes for this site.' );
		wp_send_json_error( $status );
	}

	include_once( ABSPATH . 'wp-admin/includes/class-wp-upgrader.php' );

	$current = get_site_transient( 'update_themes' );
	if ( empty( $current ) ) {
		wp_update_themes();
	}

	$skin     = new WP_Ajax_Upgrader_Skin();
	$upgrader = new Theme_Upgrader( $skin );
	$result   = $upgrader->bulk_upgrade( array( $stylesheet ) );

	if ( defined( 'WP_DEBUG' ) && WP_DEBUG ) {
		$status['debug'] = $skin->get_upgrade_messages();
	}

	if ( is_wp_error( $skin->result ) ) {
		$status['errorCode']    = $skin->result->get_error_code();
		$status['errorMessage'] = $skin->result->get_error_message();
		wp_send_json_error( $status );
	} elseif ( $skin->get_errors()->get_error_code() ) {
		$status['errorMessage'] = $skin->get_error_messages();
		wp_send_json_error( $status );
	} elseif ( is_array( $result ) && ! empty( $result[ $stylesheet ] ) ) {

		// Theme is already at the latest version.
		if ( true === $result[ $stylesheet ] ) {
			$status['errorMessage'] = $upgrader->strings['up_to_date'];
			wp_send_json_error( $status );
		}

		$theme = wp_get_theme( $stylesheet );
		if ( $theme->get( 'Version' ) ) {
			$status['newVersion'] = $theme->get( 'Version' );
		}

		wp_send_json_success( $status );
	} elseif ( false === $result ) {
		global $wp_filesystem;

		$status['errorCode']    = 'unable_to_connect_to_filesystem';
		$status['errorMessage'] = __( 'Unable to connect to the filesystem. Please confirm your credentials.' );

		// Pass through the error from WP_Filesystem if one was raised.
		if ( $wp_filesystem instanceof WP_Filesystem_Base && is_wp_error( $wp_filesystem->errors ) && $wp_filesystem->errors->get_error_code() ) {
			$status['errorMessage'] = esc_html( $wp_filesystem->errors->get_error_message() );
		}

		wp_send_json_error( $status );
	}

	// An unhandled error occurred.
	$status['errorMessage'] = __( 'Update failed.' );
	wp_send_json_error( $status );
}

/**
 * Ajax handler for deleting a theme.
 *
 * @since 4.6.0
 *
 * @see delete_theme()
 */
function wp_ajax_delete_theme() {
	check_ajax_referer( 'updates' );

	if ( empty( $_POST['slug'] ) ) {
		wp_send_json_error( array(
			'slug'         => '',
			'errorCode'    => 'no_theme_specified',
			'errorMessage' => __( 'No theme specified.' ),
		) );
	}

	$stylesheet = sanitize_key( wp_unslash( $_POST['slug'] ) );

It seems like wp_unslash($_POST['slug']) targeting wp_unslash() can also be of type array; however, sanitize_key() does only seem to accept string, maybe add an additional type check?

	$status     = array(
		'delete' => 'theme',
		'slug'   => $stylesheet,
	);

	if ( ! current_user_can( 'delete_themes' ) ) {
		$status['errorMessage'] = __( 'Sorry, you are not allowed to delete themes on this site.' );
		wp_send_json_error( $status );
	}

	if ( ! wp_get_theme( $stylesheet )->exists() ) {
		$status['errorMessage'] = __( 'The requested theme does not exist.' );
		wp_send_json_error( $status );
	}

	// Check filesystem credentials. `delete_theme()` will bail otherwise.
	$url = wp_nonce_url( 'themes.php?action=delete&stylesheet=' . urlencode( $stylesheet ), 'delete-theme_' . $stylesheet );
	ob_start();
	$credentials = request_filesystem_credentials( $url );
	ob_end_clean();
	if ( false === $credentials || ! WP_Filesystem( $credentials ) ) {

$credentials is of type boolean, but the function expects a false|array.

		global $wp_filesystem;

		$status['errorCode']    = 'unable_to_connect_to_filesystem';
		$status['errorMessage'] = __( 'Unable to connect to the filesystem. Please confirm your credentials.' );

		// Pass through the error from WP_Filesystem if one was raised.
		if ( $wp_filesystem instanceof WP_Filesystem_Base && is_wp_error( $wp_filesystem->errors ) && $wp_filesystem->errors->get_error_code() ) {
			$status['errorMessage'] = esc_html( $wp_filesystem->errors->get_error_message() );
		}

		wp_send_json_error( $status );
	}

	include_once( ABSPATH . 'wp-admin/includes/theme.php' );

	$result = delete_theme( $stylesheet );

	if ( is_wp_error( $result ) ) {
		$status['errorMessage'] = $result->get_error_message();
		wp_send_json_error( $status );
	} elseif ( false === $result ) {
		$status['errorMessage'] = __( 'Theme could not be deleted.' );
		wp_send_json_error( $status );
	}

	wp_send_json_success( $status );
}

/**
 * Ajax handler for installing a plugin.
 *
 * @since 4.6.0
 *
 * @see Plugin_Upgrader
 */
function wp_ajax_install_plugin() {
	check_ajax_referer( 'updates' );

	if ( empty( $_POST['slug'] ) ) {
		wp_send_json_error( array(
			'slug'         => '',
			'errorCode'    => 'no_plugin_specified',
			'errorMessage' => __( 'No plugin specified.' ),
		) );
	}

	$status = array(
		'install' => 'plugin',
		'slug'    => sanitize_key( wp_unslash( $_POST['slug'] ) ),

It seems like wp_unslash($_POST['slug']) targeting wp_unslash() can also be of type array; however, sanitize_key() does only seem to accept string, maybe add an additional type check?

	);

	if ( ! current_user_can( 'install_plugins' ) ) {
		$status['errorMessage'] = __( 'Sorry, you are not allowed to install plugins on this site.' );
		wp_send_json_error( $status );
	}

	include_once( ABSPATH . 'wp-admin/includes/class-wp-upgrader.php' );
	include_once( ABSPATH . 'wp-admin/includes/plugin-install.php' );

	$api = plugins_api( 'plugin_information', array(
		'slug'   => sanitize_key( wp_unslash( $_POST['slug'] ) ),

It seems like wp_unslash($_POST['slug']) targeting wp_unslash() can also be of type array; however, sanitize_key() does only seem to accept string, maybe add an additional type check?

		'fields' => array(
			'sections' => false,
		),
	) );

	if ( is_wp_error( $api ) ) {
		$status['errorMessage'] = $api->get_error_message();
		wp_send_json_error( $status );
	}

	$status['pluginName'] = $api->name;

	$skin     = new WP_Ajax_Upgrader_Skin();
	$upgrader = new Plugin_Upgrader( $skin );
	$result   = $upgrader->install( $api->download_link );

	if ( defined( 'WP_DEBUG' ) && WP_DEBUG ) {
		$status['debug'] = $skin->get_upgrade_messages();
	}

	if ( is_wp_error( $result ) ) {
		$status['errorCode']    = $result->get_error_code();
		$status['errorMessage'] = $result->get_error_message();
		wp_send_json_error( $status );
	} elseif ( is_wp_error( $skin->result ) ) {
		$status['errorCode']    = $skin->result->get_error_code();
		$status['errorMessage'] = $skin->result->get_error_message();
		wp_send_json_error( $status );
	} elseif ( $skin->get_errors()->get_error_code() ) {
		$status['errorMessage'] = $skin->get_error_messages();
		wp_send_json_error( $status );
	} elseif ( is_null( $result ) ) {
		global $wp_filesystem;

		$status['errorCode']    = 'unable_to_connect_to_filesystem';
		$status['errorMessage'] = __( 'Unable to connect to the filesystem. Please confirm your credentials.' );

		// Pass through the error from WP_Filesystem if one was raised.
		if ( $wp_filesystem instanceof WP_Filesystem_Base && is_wp_error( $wp_filesystem->errors ) && $wp_filesystem->errors->get_error_code() ) {
			$status['errorMessage'] = esc_html( $wp_filesystem->errors->get_error_message() );
		}

		wp_send_json_error( $status );
	}

	$install_status = install_plugin_install_status( $api );

	if ( current_user_can( 'activate_plugins' ) && is_plugin_inactive( $install_status['file'] ) ) {
		$status['activateUrl'] = add_query_arg( array(
			'_wpnonce' => wp_create_nonce( 'activate-plugin_' . $install_status['file'] ),
			'action'   => 'activate',
			'plugin'   => $install_status['file'],
		), network_admin_url( 'plugins.php' ) );
	}

	if ( is_multisite() && current_user_can( 'manage_network_plugins' ) ) {
		$status['activateUrl'] = add_query_arg( array( 'networkwide' => 1 ), $status['activateUrl'] );
	}

	wp_send_json_success( $status );
}

/**
 * Ajax handler for updating a plugin.
 *
 * @since 4.2.0
 *
 * @see Plugin_Upgrader
 */
function wp_ajax_update_plugin() {
	check_ajax_referer( 'updates' );

	if ( empty( $_POST['plugin'] ) || empty( $_POST['slug'] ) ) {
		wp_send_json_error( array(
			'slug'         => '',
			'errorCode'    => 'no_plugin_specified',
			'errorMessage' => __( 'No plugin specified.' ),
		) );
	}

	$plugin = plugin_basename( sanitize_text_field( wp_unslash( $_POST['plugin'] ) ) );

It seems like wp_unslash($_POST['plugin']) targeting wp_unslash() can also be of type array; however, sanitize_text_field() does only seem to accept string, maybe add an additional type check?

	$status = array(
		'update'     => 'plugin',
		'slug'       => sanitize_key( wp_unslash( $_POST['slug'] ) ),

It seems like wp_unslash($_POST['slug']) targeting wp_unslash() can also be of type array; however, sanitize_key() does only seem to accept string, maybe add an additional type check?

		'oldVersion' => '',
		'newVersion' => '',
	);

	if ( ! current_user_can( 'update_plugins' ) || 0 !== validate_file( $plugin ) ) {
		$status['errorMessage'] = __( 'Sorry, you are not allowed to update plugins for this site.' );
		wp_send_json_error( $status );
	}

	$plugin_data          = get_plugin_data( WP_PLUGIN_DIR . '/' . $plugin );
	$status['plugin']     = $plugin;
	$status['pluginName'] = $plugin_data['Name'];

	if ( $plugin_data['Version'] ) {
		/* translators: %s: Plugin version */
		$status['oldVersion'] = sprintf( __( 'Version %s' ), $plugin_data['Version'] );
	}

	include_once ABSPATH . 'wp-admin/includes/class-wp-upgrader.php';

	wp_update_plugins();

	$skin     = new WP_Ajax_Upgrader_Skin();
	$upgrader = new Plugin_Upgrader( $skin );
	$result   = $upgrader->bulk_upgrade( array( $plugin ) );

	if ( defined( 'WP_DEBUG' ) && WP_DEBUG ) {
		$status['debug'] = $skin->get_upgrade_messages();
	}

	if ( is_wp_error( $skin->result ) ) {
		$status['errorCode']    = $skin->result->get_error_code();
		$status['errorMessage'] = $skin->result->get_error_message();
		wp_send_json_error( $status );
	} elseif ( $skin->get_errors()->get_error_code() ) {
		$status['errorMessage'] = $skin->get_error_messages();
		wp_send_json_error( $status );
	} elseif ( is_array( $result ) && ! empty( $result[ $plugin ] ) ) {
		$plugin_update_data = current( $result );

		/*
		 * If the `update_plugins` site transient is empty (e.g. when you update
		 * two plugins in quick succession before the transient repopulates),
		 * this may be the return.
		 *
		 * Preferably something can be done to ensure `update_plugins` isn't empty.
		 * For now, surface some sort of error here.
		 */
		if ( true === $plugin_update_data ) {
			$status['errorMessage'] = __( 'Plugin update failed.' );
			wp_send_json_error( $status );
		}

		$plugin_data = get_plugins( '/' . $result[ $plugin ]['destination_name'] );
		$plugin_data = reset( $plugin_data );

		if ( $plugin_data['Version'] ) {
			/* translators: %s: Plugin version */
			$status['newVersion'] = sprintf( __( 'Version %s' ), $plugin_data['Version'] );
		}
		wp_send_json_success( $status );
	} elseif ( false === $result ) {
		global $wp_filesystem;

		$status['errorCode']    = 'unable_to_connect_to_filesystem';
		$status['errorMessage'] = __( 'Unable to connect to the filesystem. Please confirm your credentials.' );

		// Pass through the error from WP_Filesystem if one was raised.
		if ( $wp_filesystem instanceof WP_Filesystem_Base && is_wp_error( $wp_filesystem->errors ) && $wp_filesystem->errors->get_error_code() ) {
			$status['errorMessage'] = esc_html( $wp_filesystem->errors->get_error_message() );
		}

		wp_send_json_error( $status );
	}

	// An unhandled error occurred.
	$status['errorMessage'] = __( 'Plugin update failed.' );
	wp_send_json_error( $status );
}

/**
 * Ajax handler for deleting a plugin.
 *
 * @since 4.6.0
 *
 * @see delete_plugins()
 */
function wp_ajax_delete_plugin() {
	check_ajax_referer( 'updates' );

	if ( empty( $_POST['slug'] ) || empty( $_POST['plugin'] ) ) {
		wp_send_json_error( array(
			'slug'         => '',
			'errorCode'    => 'no_plugin_specified',
			'errorMessage' => __( 'No plugin specified.' ),
		) );
	}

	$plugin = plugin_basename( sanitize_text_field( wp_unslash( $_POST['plugin'] ) ) );

It seems like wp_unslash($_POST['plugin']) targeting wp_unslash() can also be of type array; however, sanitize_text_field() does only seem to accept string, maybe add an additional type check?

	$status = array(
		'delete' => 'plugin',
		'slug'   => sanitize_key( wp_unslash( $_POST['slug'] ) ),

It seems like wp_unslash($_POST['slug']) targeting wp_unslash() can also be of type array; however, sanitize_key() does only seem to accept string, maybe add an additional type check?

	);

	if ( ! current_user_can( 'delete_plugins' ) || 0 !== validate_file( $plugin ) ) {
		$status['errorMessage'] = __( 'Sorry, you are not allowed to delete plugins for this site.' );
		wp_send_json_error( $status );
	}

	$plugin_data          = get_plugin_data( WP_PLUGIN_DIR . '/' . $plugin );
	$status['plugin']     = $plugin;
	$status['pluginName'] = $plugin_data['Name'];

	if ( is_plugin_active( $plugin ) ) {
		$status['errorMessage'] = __( 'You cannot delete a plugin while it is active on the main site.' );
		wp_send_json_error( $status );
	}

	// Check filesystem credentials. `delete_plugins()` will bail otherwise.
	$url = wp_nonce_url( 'plugins.php?action=delete-selected&verify-delete=1&checked[]=' . $plugin, 'bulk-plugins' );
	ob_start();
	$credentials = request_filesystem_credentials( $url );
	ob_end_clean();
	if ( false === $credentials || ! WP_Filesystem( $credentials ) ) {

$credentials is of type boolean, but the function expects a false|array.

		global $wp_filesystem;

		$status['errorCode']    = 'unable_to_connect_to_filesystem';
		$status['errorMessage'] = __( 'Unable to connect to the filesystem. Please confirm your credentials.' );

		// Pass through the error from WP_Filesystem if one was raised.
		if ( $wp_filesystem instanceof WP_Filesystem_Base && is_wp_error( $wp_filesystem->errors ) && $wp_filesystem->errors->get_error_code() ) {
			$status['errorMessage'] = esc_html( $wp_filesystem->errors->get_error_message() );
		}

		wp_send_json_error( $status );
	}

	$result = delete_plugins( array( $plugin ) );

	if ( is_wp_error( $result ) ) {
		$status['errorMessage'] = $result->get_error_message();
		wp_send_json_error( $status );
	} elseif ( false === $result ) {
		$status['errorMessage'] = __( 'Plugin could not be deleted.' );
		wp_send_json_error( $status );
	}

	wp_send_json_success( $status );
}

/**
 * Ajax handler for searching plugins.
 *
 * @since 4.6.0
 *
 * @global string $s Search term.
 */
function wp_ajax_search_plugins() {
	check_ajax_referer( 'updates' );

	$pagenow = isset( $_POST['pagenow'] ) ? sanitize_key( $_POST['pagenow'] ) : '';
	if ( 'plugins-network' === $pagenow || 'plugins' === $pagenow ) {
		set_current_screen( $pagenow );
	}

	/** @var WP_Plugins_List_Table $wp_list_table */
	$wp_list_table = _get_list_table( 'WP_Plugins_List_Table', array(
		'screen' => get_current_screen(),
	) );

	$status = array();

	if ( ! $wp_list_table->ajax_user_can() ) {
		$status['errorMessage'] = __( 'Sorry, you are not allowed to manage plugins for this site.' );
		wp_send_json_error( $status );
	}

	// Set the correct requester, so pagination works.
	$_SERVER['REQUEST_URI'] = add_query_arg( array_diff_key( $_POST, array(
		'_ajax_nonce' => null,
		'action'      => null,
	) ), network_admin_url( 'plugins.php', 'relative' ) );

	$GLOBALS['s'] = wp_unslash( $_POST['s'] );

	$wp_list_table->prepare_items();

	ob_start();
	$wp_list_table->display();
	$status['count'] = count( $wp_list_table->items );
	$status['items'] = ob_get_clean();

	wp_send_json_success( $status );
}

/**
 * Ajax handler for searching plugins to install.
 *
 * @since 4.6.0
 */
function wp_ajax_search_install_plugins() {
	check_ajax_referer( 'updates' );

	$pagenow = isset( $_POST['pagenow'] ) ? sanitize_key( $_POST['pagenow'] ) : '';
	if ( 'plugin-install-network' === $pagenow || 'plugin-install' === $pagenow ) {
		set_current_screen( $pagenow );
	}

	/** @var WP_Plugin_Install_List_Table $wp_list_table */
	$wp_list_table = _get_list_table( 'WP_Plugin_Install_List_Table', array(
		'screen' => get_current_screen(),
	) );

	$status = array();

	if ( ! $wp_list_table->ajax_user_can() ) {
		$status['errorMessage'] = __( 'Sorry, you are not allowed to manage plugins for this site.' );
		wp_send_json_error( $status );
	}

	// Set the correct requester, so pagination works.
	$_SERVER['REQUEST_URI'] = add_query_arg( array_diff_key( $_POST, array(
		'_ajax_nonce' => null,
		'action'      => null,
	) ), network_admin_url( 'plugin-install.php', 'relative' ) );

	$wp_list_table->prepare_items();

	ob_start();
	$wp_list_table->display();
	$status['count'] = (int) $wp_list_table->get_pagination_arg( 'total_items' );
	$status['items'] = ob_get_clean();

	wp_send_json_success( $status );
}