Cron API: Introduce `wp_unschedule_hook()` to clear all events attached to a hook.

This complements `wp_clear_scheduled_hook()`, which only clears events attached with specific arguments.

Props arena, mordauk, jrf.
Fixes #18997.
Built from https://develop.svn.wordpress.org/trunk@40965


git-svn-id: http://core.svn.wordpress.org/trunk@40815 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/cron.php

@@ -191,7 +191,7 @@ function wp_unschedule_event( $timestamp, $hook, $args = array() ) {
 }
 
 /**
- * Unschedule all events attached to the specified hook.
+ * Unschedule all events attached to the hook with the specified arguments.
  *
  * @since 2.1.0
  *
@@ -221,6 +221,29 @@ function wp_clear_scheduled_hook( $hook, $args = array() ) {
 	}
 }
 
+/**
+ * Unschedule all events attached to the hook.
+ *
+ * Can be useful for plugins when deactivating to clean up the cron queue.
+ *
+ * @since 4.9.0
+ *
+ * @param string $hook Action hook, the execution of which will be unscheduled.
+ */
+function wp_unschedule_hook( $hook ) {
+	$crons = _get_cron_array();
+
+	foreach( $crons as $timestamp => $args ) {
+		unset( $crons[ $timestamp ][ $hook ] );
+
+		if ( empty( $crons[ $timestamp ] ) ) {
+			unset( $crons[ $timestamp ] );
+		}
+	}
+
+	_set_cron_array( $crons );
+}
+
 /**
  * Retrieve the next timestamp for an event.
  *

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.9-alpha-40964';
+$wp_version = '4.9-alpha-40965';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.