Posts, Post Types: Additional functions to check if a post is publicly viewable.

Introduces `is_post_status_viewable()` as a sibling to `is_post_type_viewable()`. Internal and protected statuses are never considered viewable. For built in posts statuses the `public` attribute is checked, for custom statuses the `publicly_queryable` attribute is checked.

Introduces `is_post_publicly_viewable()` for determining if an individual post can be viewed by logged out users. A post is considered viewable if both `is_post_status_viewable()` and `is_post_type_viewable()` return `true` for the post's attributes.

Additionally modifies `is_post_type_viewable()` to return `false` if an unregistered post type is passed to the function to avoid attempting to access properties on a non-object.

Props peterwilsoncc, SergeyBiryukov, whyisjake, TimothyBlynJacobs.
Fixes #49380.


Built from https://develop.svn.wordpress.org/trunk@50130


git-svn-id: http://core.svn.wordpress.org/trunk@49809 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/post.php

@@ -2019,9 +2019,67 @@ function is_post_type_viewable( $post_type ) {
 		}
 	}
 
+	if ( ! is_object( $post_type ) ) {
+		return false;
+	}
+
 	return $post_type->publicly_queryable || ( $post_type->_builtin && $post_type->public );
 }
 
+/**
+ * Determine whether a post status is considered "viewable".
+ *
+ * For built-in post statuses such as publish and private, the 'public' value will be evaluted.
+ * For all others, the 'publicly_queryable' value will be used.
+ *
+ * @since 5.7.0
+ *
+ * @param string|stdClass $post_status Post status name or object.
+ * @return bool Whether the post status should be considered viewable.
+ */
+function is_post_status_viewable( $post_status ) {
+	if ( is_scalar( $post_status ) ) {
+		$post_status = get_post_status_object( $post_status );
+		if ( ! $post_status ) {
+			return false;
+		}
+	}
+
+	if (
+		! is_object( $post_status ) ||
+		$post_status->internal ||
+		$post_status->protected
+	) {
+		return false;
+	}
+
+	return $post_status->publicly_queryable || ( $post_status->_builtin && $post_status->public );
+}
+
+/**
+ * Determine whether a post is publicly viewable.
+ *
+ * Posts are considered publicly viewable if both the post status and post type
+ * are viewable.
+ *
+ * @since 5.7.0
+ *
+ * @param int|WP_Post|null $post Optional. Post ID or post object. Defaults to global $post.
+ * @return bool Whether the post is publicly viewable.
+ */
+function is_post_publicly_viewable( $post = null ) {
+	$post = get_post( $post );
+
+	if ( ! $post ) {
+		return false;
+	}
+
+	$post_type   = get_post_type( $post );
+	$post_status = get_post_status( $post );
+
+	return is_post_type_viewable( $post_type ) && is_post_status_viewable( $post_status );
+}
+
 /**
  * Retrieves an array of the latest posts, or posts matching the given criteria.
  *

wp-includes/version.php

@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.7-alpha-50129';
+$wp_version = '5.7-alpha-50130';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.