From 7afa6591c09f784ffee8c257223bc4a4e7be664b Mon Sep 17 00:00:00 2001
From: EpopE <github@intersel.org>
Date: Thu, 30 Apr 2026 12:02:10 +0200
Subject: [PATCH] Implement catch-up behavior for cron jobs

Add a cron_catchup system option to control how missed executions are handled.

When disabled, cronjobs are always rescheduled from the current time, avoiding catch-up loops after downtime.

When enabled, the existing behavior is preserved, with a safeguard against outdated nextrun values to prevent infinite execution loops.
---
 .../processors/web/cron/run.class.php         | 24 +++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

diff --git a/core/components/cronmanager/processors/web/cron/run.class.php b/core/components/cronmanager/processors/web/cron/run.class.php
index f0ecc5e..2bbee81 100755
--- a/core/components/cronmanager/processors/web/cron/run.class.php
+++ b/core/components/cronmanager/processors/web/cron/run.class.php
@@ -69,10 +69,30 @@ private function runCronjobs($success)
         }
         $c->sortby('nextrun');
 
+        // Get catch-up behavior option (default: enabled for backward compatibility)
+        // 1 = enable catch-up (original behavior)
+        // 0 = disable catch-up (reschedule from current time)
+        $catchup = (int)$this->cronmanager->getOption('cron_enable_catchup', null, 0);
+            
         /** @var modCronjob $cronjob */
         $cronjobs = $this->modx->getIterator('modCronjob', $c);
         foreach ($cronjobs as $cronjob) {
+            // Determine initial base datetime for scheduling
             $rundatetime = ($cronjob->get('nextrun')) ? $cronjob->get('nextrun') : date('Y-m-d H:i:s');
+           
+            if (!$catchup) {
+                // Catch-up disabled:
+                // Always reschedule based on the current time to avoid executing missed runs
+                $rundatetime = date('Y-m-d H:i:s');
+            } else {
+                // Catch-up enabled:
+                // If nextrun is significantly in the past, reset to current time
+                // This prevents excessive back-to-back executions ("catch-up loops")
+                if (strtotime($rundatetime) < time() - 60) {
+                    $rundatetime = date('Y-m-d H:i:s');
+                }
+            }
+
             $properties = $cronjob->get('properties');
             if (!empty($properties)) {
                 /** @var modPropertySet $propset */
@@ -140,9 +160,9 @@ private function runCronjobs($success)
             $logs = [$log];
 
             $cronjob->set('lastrun', $rundatetime);
-            if ($this->cronmanager->getOption('daylight_saving') && $cronjob->get('minutes') > 60) {
+            if ($this->cronmanager->getOption('daylight_saving') && $cronjob->get('minutes') > 60) {    
                 $cronjob->set('nextrun', date('Y-m-d H:i:s', strtotime($cronjob->get('minutes') . ' minutes', (strtotime($rundatetime)))));
-            } else {
+            } else {    
                 $cronjob->set('nextrun', date('Y-m-d H:i:s', (strtotime($rundatetime) + ($cronjob->get('minutes') * 60))));
             }
             $cronjob->set('running', false);