From 5603d025be581fbeeee20bcd4bb96ebfea1aad1a Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Mon, 4 May 2026 13:22:13 +0000
Subject: [PATCH] fix: ensure trigger_state written last in zmTriggerEventOn to
 fix 1/3 event trigger rate

Agent-Logs-Url: https://github.com/ZoneMinder/zoneminder/sessions/68794b2b-7137-4888-b66e-20c629112a57

Co-authored-by: connortechnology <925519+connortechnology@users.noreply.github.com>
---
 scripts/ZoneMinder/lib/ZoneMinder/Memory.pm.in | 7 +++++--
 src/zm_monitor.cpp                             | 4 +++-
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/scripts/ZoneMinder/lib/ZoneMinder/Memory.pm.in b/scripts/ZoneMinder/lib/ZoneMinder/Memory.pm.in
index 27a084e21..5eb24f389 100644
--- a/scripts/ZoneMinder/lib/ZoneMinder/Memory.pm.in
+++ b/scripts/ZoneMinder/lib/ZoneMinder/Memory.pm.in
@@ -605,15 +605,18 @@ sub zmTriggerEventOn {
   my $text = shift;
   my $showtext = shift;
 
+  # Write score/cause/text before trigger_state so the analysis process always
+  # reads complete trigger data when it sees TRIGGER_ON.  Perl hash iteration
+  # order is non-deterministic, so trigger_state must be written in a separate
+  # call that executes after all data fields are already in shared memory.
   my $values = {
     'trigger_data:trigger_score' => $score,
     'trigger_data:trigger_cause' => $cause,
   };
   $values->{'trigger_data:trigger_text'} = $text if defined($text);
   $values->{'trigger_data:trigger_showtext'} = $showtext if defined($showtext);
-  $values->{'trigger_data:trigger_state'} = TRIGGER_ON; # Write state last so event not read incomplete
-
   zmMemWrite($monitor, $values);
+  zmMemWrite($monitor, {'trigger_data:trigger_state' => TRIGGER_ON}); # Write state last so event not read incomplete
 }
 
 sub zmTriggerEventOff {
diff --git a/src/zm_monitor.cpp b/src/zm_monitor.cpp
index 27591b0d1..7fe6af380 100644
--- a/src/zm_monitor.cpp
+++ b/src/zm_monitor.cpp
@@ -1452,10 +1452,12 @@ void Monitor::UpdateAdaptiveSkip() {
 }
 
 void Monitor::ForceAlarmOn( int force_score, const char *force_cause, const char *force_text ) {
-  trigger_data->trigger_state = TriggerState::TRIGGER_ON;
+  // Write score/cause/text before trigger_state so the analysis thread always
+  // reads complete trigger data when it observes TRIGGER_ON.
   trigger_data->trigger_score = force_score;
   strncpy(trigger_data->trigger_cause, force_cause, sizeof(trigger_data->trigger_cause)-1);
   strncpy(trigger_data->trigger_text, force_text, sizeof(trigger_data->trigger_text)-1);
+  trigger_data->trigger_state = TriggerState::TRIGGER_ON;
 }
 
 void Monitor::ForceAlarmOff() {