Cron API: Run alternative wp-cron later, do not run on archived blogs.

Runs cron jobs later on sites using alternative cron, ie the `ALTERNATE_WP_CRON` constant is true, to more closely match when standard cron jobs are run. Jobs now run on the `wp_loaded` hook at priority `20`. Prior to this change they would run on the `init` hook. This ensures custom post types and taxonomies are registered prior to the jobs running.

This change also prevents alternative wp-cron from running on archived or suspended multisite blogs as these are shut down prior to the `wp_loaded` hook from running.

Moves the existing functionality of `wp_cron()` in to a new private function `_wp_cron()`.

Props flixos90, jeremyfelt, johnbillion, jrf, kurtpayne, nacin, peterwilsoncc, prettyboymp, r-a-y, ryan, stevenkword, swissspidy.
Fixes #20537, #24160.


Built from https://develop.svn.wordpress.org/trunk@50135


git-svn-id: http://core.svn.wordpress.org/trunk@49814 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/cron.php

@@ -744,7 +744,10 @@ function spawn_cron( $gmt_time = 0 ) {
 }
 
 /**
- * Run scheduled callbacks or spawn cron for all scheduled events.
+ * Register _wp_cron() to run on the {@see 'wp_loaded'} action.
+ *
+ * If the {@see 'wp_loaded'} action has already fired, this function calls
+ * _wp_cron() directly.
  *
  * Warning: This function may return Boolean FALSE, but may also return a non-Boolean
  * value which evaluates to FALSE. For information about casting to booleans see the
@@ -753,11 +756,35 @@ function spawn_cron( $gmt_time = 0 ) {
  *
  * @since 2.1.0
  * @since 5.1.0 Return value added to indicate success or failure.
+ * @since 5.7.0 Functionality moved to _wp_cron() to which this becomes a wrapper.
+ *
+ * @return bool|int|void On success an integer indicating number of events spawned (0 indicates no
+ *                       events needed to be spawned), false if spawning fails for one or more events or
+ *                       void if the function registered _wp_cron() to run on the action.
+ */
+function wp_cron() {
+	if ( did_action( 'wp_loaded' ) ) {
+		return _wp_cron();
+	}
+
+	add_action( 'wp_loaded', '_wp_cron', 20 );
+}
+
+/**
+ * Run scheduled callbacks or spawn cron for all scheduled events.
+ *
+ * Warning: This function may return Boolean FALSE, but may also return a non-Boolean
+ * value which evaluates to FALSE. For information about casting to booleans see the
+ * {@link https://www.php.net/manual/en/language.types.boolean.php PHP documentation}. Use
+ * the `===` operator for testing the return value of this function.
+ *
+ * @since 5.7.0
+ * @access private
  *
  * @return int|false On success an integer indicating number of events spawned (0 indicates no
  *                   events needed to be spawned), false if spawning fails for one or more events.
  */
-function wp_cron() {
+function _wp_cron() {
 	// Prevent infinite loops caused by lack of wp-cron.php.
 	if ( strpos( $_SERVER['REQUEST_URI'], '/wp-cron.php' ) !== false || ( defined( 'DISABLE_WP_CRON' ) && DISABLE_WP_CRON ) ) {
 		return 0;

wp-includes/version.php

@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.7-alpha-50134';
+$wp_version = '5.7-alpha-50135';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.