FIX: resets pending automations only if necessary (#26685)

Prior to this fix, any change to an automation would reset `pending_automations`, now we only do it if any value related to recurrence (start_date, interval, frequency, execute_at...) has been changed.

It means that any trigger creating `pending_automations` now needs to manage them in the `on_update` callback.

plugins/automation/lib/discourse_automation/triggers/point_in_time.rb

@@ -3,11 +3,17 @@
 DiscourseAutomation::Triggerable.add(DiscourseAutomation::Triggers::POINT_IN_TIME) do
   field :execute_at, component: :date_time, required: true
 
-  on_update do |automation, metadata|
-    # prevents creating a new pending automation on save when date is expired
-    execute_at = metadata.dig("execute_at", "value")
-    if execute_at && execute_at > Time.zone.now
-      automation.pending_automations.create!(execute_at: execute_at)
+  on_update do |automation, fields, previous_fields|
+    execute_at = fields.dig("execute_at", "value")
+    previous_execute_at = previous_fields&.dig("execute_at", "value")
+
+    if execute_at != previous_execute_at
+      automation.pending_automations.destroy_all
+
+      # prevents creating a new pending automation on save when date is expired
+      if execute_at && execute_at > Time.zone.now
+        automation.pending_automations.create!(execute_at: execute_at)
+      end
     end
   end
 end

plugins/automation/lib/discourse_automation/triggers/recurring.rb

@@ -13,12 +13,27 @@ module DiscourseAutomation
         { id: "year", name: "discourse_automation.triggerables.recurring.frequencies.year" },
       ]
 
-      def self.setup_pending_automation(automation, fields)
-        automation.pending_automations.destroy_all
+      def self.setup_pending_automation(automation, fields, previous_fields)
+        start_date = fields.dig("start_date", "value")
+        interval = fields.dig("recurrence", "value", "interval")
+        frequency = fields.dig("recurrence", "value", "frequency")
 
-        return unless start_date = fields.dig("start_date", "value")
-        return unless interval = fields.dig("recurrence", "value", "interval")
-        return unless frequency = fields.dig("recurrence", "value", "frequency")
+        # this case is not possible in practice but better be safe
+        if !start_date || !interval || !frequency
+          automation.pending_automations.destroy_all
+          return
+        end
+
+        previous_start_date = previous_fields&.dig("start_date", "value")
+        previous_interval = previous_fields&.dig("recurrence", "value", "interval")
+        previous_frequency = previous_fields&.dig("recurrence", "value", "frequency")
+
+        if previous_start_date != start_date || previous_interval != interval ||
+             previous_frequency != frequency
+          automation.pending_automations.destroy_all
+        else
+          return
+        end
 
         start_date = Time.parse(start_date)
         byday = start_date.strftime("%A").upcase[0, 2]
@@ -82,11 +97,19 @@ DiscourseAutomation::Triggerable.add(DiscourseAutomation::Triggers::RECURRING) d
         required: true
   field :start_date, component: :date_time, required: true
 
-  on_update do |automation, fields|
-    DiscourseAutomation::Triggers::Recurring.setup_pending_automation(automation, fields)
+  on_update do |automation, fields, previous_fields|
+    DiscourseAutomation::Triggers::Recurring.setup_pending_automation(
+      automation,
+      fields,
+      previous_fields,
+    )
   end
-  on_call do |automation, fields|
-    DiscourseAutomation::Triggers::Recurring.setup_pending_automation(automation, fields)
+  on_call do |automation, fields, previous_fields|
+    DiscourseAutomation::Triggers::Recurring.setup_pending_automation(
+      automation,
+      fields,
+      previous_fields,
+    )
   end
 
   enable_manual_trigger