Fix halloweens races (#70874)

* Fixes halloween races.
- Fixes a race condition involve checking for holidays befores SSevents is instantiated. Now, holiday checking is done through a helper, which will ensure the holidays list is created and filled before checked.

code/controllers/subsystem/communications.dm

@@ -42,7 +42,7 @@ SUBSYSTEM_DEF(communications)
  * * user - Mob who called the meeting
  */
 /datum/controller/subsystem/communications/proc/can_make_emergency_meeting(mob/living/user)
-	if(!(SSevents.holidays && SSevents.holidays[APRIL_FOOLS]))
+	if(!check_holidays(APRIL_FOOLS))
 		return FALSE
 	else if(COOLDOWN_FINISHED(src, emergency_meeting_cooldown))
 		return TRUE

code/controllers/subsystem/events.dm

@@ -11,7 +11,6 @@ SUBSYSTEM_DEF(events)
 	var/frequency_lower = 1800 //3 minutes lower bound.
 	var/frequency_upper = 6000 //10 minutes upper bound. Basically an event will happen every 3 to 10 minutes.
 
-	var/list/holidays //List of all holidays occuring today or null if no holidays
 	var/wizardmode = FALSE
 
 /datum/controller/subsystem/events/Initialize()
@@ -21,7 +20,9 @@ SUBSYSTEM_DEF(events)
 			continue //don't want this one! leave it for the garbage collector
 		control += E //add it to the list of all events (controls)
 	reschedule()
-	getHoliday()
+	// Instantiate our holidays list if it hasn't been already
+	if(isnull(GLOB.holidays))
+		fill_holidays()
 	return SS_INIT_SUCCESS
 
 
@@ -92,33 +93,58 @@ SUBSYSTEM_DEF(events)
 	else if(. == EVENT_READY)
 		E.runEvent(random = TRUE)
 
-/*
-//////////////
-// HOLIDAYS //
-//////////////
-//Uncommenting ALLOW_HOLIDAYS in config.txt will enable holidays
 
-//It's easy to add stuff. Just add a holiday datum in code/modules/holiday/holidays.dm
-//You can then check if it's a special day in any code in the game by doing if(SSevents.holidays["Groundhog Day"])
+/datum/controller/subsystem/events/proc/toggleWizardmode()
+	wizardmode = !wizardmode
+	message_admins("Summon Events has been [wizardmode ? "enabled, events will occur every [SSevents.frequency_lower / 600] to [SSevents.frequency_upper / 600] minutes" : "disabled"]!")
+	log_game("Summon Events was [wizardmode ? "enabled" : "disabled"]!")
 
-//You can also make holiday random events easily thanks to Pete/Gia's system.
-//simply make a random event normally, then assign it a holidayID string which matches the holiday's name.
-//Anything with a holidayID, which isn't in the holidays list, will never occur.
 
-//Please, Don't spam stuff up with stupid stuff (key example being april-fools Pooh/ERP/etc),
-//And don't forget: CHECK YOUR CODE!!!! We don't want any zero-day bugs which happen only on holidays and never get found/fixed!
+/datum/controller/subsystem/events/proc/resetFrequency()
+	frequency_lower = initial(frequency_lower)
+	frequency_upper = initial(frequency_upper)
 
-//////////////////////////////////////////////////////////////////////////////////////////////////////////
-//ALSO, MOST IMPORTANTLY: Don't add stupid stuff! Discuss bonus content with Project-Heads first please!//
-//////////////////////////////////////////////////////////////////////////////////////////////////////////
-*/
+/**
+ * HOLIDAYS
+ *
+ * Uncommenting ALLOW_HOLIDAYS in config.txt will enable holidays
+ *
+ * It's easy to add stuff. Just add a holiday datum in code/modules/holiday/holidays.dm
+ * You can then check if it's a special day in any code in the game by calling check_holidays("Groundhog Day")
+ *
+ * You can also make holiday random events easily thanks to Pete/Gia's system.
+ * simply make a random event normally, then assign it a holidayID string which matches the holiday's name.
+ * Anything with a holidayID, which isn't in the holidays list, will never occur.
+ *
+ * Please, Don't spam stuff up with stupid stuff (key example being april-fools Pooh/ERP/etc),
+ * and don't forget: CHECK YOUR CODE!!!! We don't want any zero-day bugs which happen only on holidays and never get found/fixed!
+ */
+GLOBAL_LIST(holidays)
 
-//sets up the holidays and holidays list
-/datum/controller/subsystem/events/proc/getHoliday()
+/**
+ * Checks that the passed holiday is located in the global holidays list.
+ *
+ * Returns a holiday datum, or null if it's not that holiday.
+ */
+/proc/check_holidays(holiday_to_find)
 	if(!CONFIG_GET(flag/allow_holidays))
 		return // Holiday stuff was not enabled in the config!
-	for(var/H in subtypesof(/datum/holiday))
-		var/datum/holiday/holiday = new H()
+
+	if(isnull(GLOB.holidays) && !fill_holidays())
+		return // Failed to generate holidays, for some reason
+
+	return GLOB.holidays[holiday_to_find]
+
+/**
+ * Fills the holidays list if applicable, or leaves it an empty list.
+ */
+/proc/fill_holidays()
+	if(!CONFIG_GET(flag/allow_holidays))
+		return FALSE // Holiday stuff was not enabled in the config!
+
+	GLOB.holidays = list()
+	for(var/holiday_type in subtypesof(/datum/holiday))
+		var/datum/holiday/holiday = new holiday_type()
 		var/delete_holiday = TRUE
 		for(var/timezone in holiday.timezones)
 			var/time_in_timezone = world.realtime + timezone HOURS
@@ -130,24 +156,16 @@ SUBSYSTEM_DEF(events)
 
 			if(holiday.shouldCelebrate(DD, MM, YYYY, DDD))
 				holiday.celebrate()
-				LAZYSET(holidays, holiday.name, holiday)
+				GLOB.holidays[holiday.name] = holiday
 				delete_holiday = FALSE
 				break
 		if(delete_holiday)
 			qdel(holiday)
 
-	if(holidays)
-		holidays = shuffle(holidays)
+	if(GLOB.holidays.len)
+		shuffle_inplace(GLOB.holidays)
 		// regenerate station name because holiday prefixes.
 		set_station_name(new_station_name())
 		world.update_status()
 
-/datum/controller/subsystem/events/proc/toggleWizardmode()
-	wizardmode = !wizardmode
-	message_admins("Summon Events has been [wizardmode ? "enabled, events will occur every [SSevents.frequency_lower / 600] to [SSevents.frequency_upper / 600] minutes" : "disabled"]!")
-	log_game("Summon Events was [wizardmode ? "enabled" : "disabled"]!")
-
-
-/datum/controller/subsystem/events/proc/resetFrequency()
-	frequency_lower = initial(frequency_lower)
-	frequency_upper = initial(frequency_upper)
+	return TRUE

code/controllers/subsystem/ticker.dm

@@ -272,10 +272,10 @@ SUBSYSTEM_DEF(ticker)
 	current_state = GAME_STATE_PLAYING
 	Master.SetRunLevel(RUNLEVEL_GAME)
 
-	if(SSevents.holidays)
+	if(length(GLOB.holidays))
 		to_chat(world, span_notice("and..."))
-		for(var/holidayname in SSevents.holidays)
-			var/datum/holiday/holiday = SSevents.holidays[holidayname]
+		for(var/holidayname in GLOB.holidays)
+			var/datum/holiday/holiday = GLOB.holidays[holidayname]
 			to_chat(world, "<h4>[holiday.greet()]</h4>")
 
 	PostSetup()