[MIRROR] Fixes smart pipe & cryo gas reallocation (#2070) (#2954)

* Fixes smart pipe & cryo gas reallocation (#82701)

## About The Pull Request

**1. Smart Pipe Problem**
 - Fill a pipe with any gas, plasma for e.g.
 - Unwrench the pipe to deconstruct
- The pressure sends you flying but notice plasma is nowhere to be seen
from the now destroyed pipe
 
**2. Cryo pipe connector problem**
The gas gets reallocated when the object is deleted. We only want this
when its deconstructed not deleted to prevent any side effects

This PR fixes them

## Changelog
:cl:
fix: smart pipes release their gases into the air when unwrenched
fix: cryo pipe connector component has no side effects of gas
reallocation when deleted
/:cl:

* Fixes smart pipe & cryo gas reallocation

---------

Co-authored-by: NovaBot <[email protected]>
Co-authored-by: SyncIt21 <[email protected]>

code/modules/atmospherics/machinery/components/unary_devices/machine_connector.dm

@@ -5,14 +5,12 @@
 	var/obj/machinery/atmospherics/components/unary/gas_connector
 
 /datum/gas_machine_connector/New(location, obj/machinery/connecting_machine = null, direction = SOUTH, gas_volume)
-	gas_connector = new(location)
-
 	connected_machine = connecting_machine
 	if(!connected_machine)
-		QDEL_NULL(gas_connector)
 		qdel(src)
 		return
 
+	gas_connector = new(location)
 	gas_connector.dir = connected_machine.dir
 	gas_connector.airs[1].volume = gas_volume
 
@@ -41,7 +39,8 @@
 	RegisterSignal(connected_machine, COMSIG_MOVABLE_PRE_MOVE, PROC_REF(pre_move_connected_machine))
 	RegisterSignal(connected_machine, COMSIG_MOVABLE_MOVED, PROC_REF(moved_connected_machine))
 	RegisterSignal(connected_machine, COMSIG_MACHINERY_DEFAULT_ROTATE_WRENCH, PROC_REF(wrenched_connected_machine))
-	RegisterSignal(connected_machine, COMSIG_QDELETING, PROC_REF(deconstruct_connected_machine))
+	RegisterSignal(connected_machine, COMSIG_OBJ_DECONSTRUCT, PROC_REF(deconstruct_connected_machine))
+	RegisterSignal(connected_machine, COMSIG_QDELETING, PROC_REF(destroy_connected_machine))
 
 /**
  * Unregister the signals previously registered
@@ -51,7 +50,8 @@
 		COMSIG_MOVABLE_MOVED,
 		COMSIG_MOVABLE_PRE_MOVE,
 		COMSIG_MACHINERY_DEFAULT_ROTATE_WRENCH,
-		COMSIG_QDELETING,
+		COMSIG_OBJ_DECONSTRUCT,
+		COMSIG_QDELETING
 	))
 
 /**
@@ -82,12 +82,18 @@
  */
 /datum/gas_machine_connector/proc/deconstruct_connected_machine()
 	SIGNAL_HANDLER
+
 	relocate_airs()
+
+/**
+ * Called when the machine has been destroyed
+ */
+/datum/gas_machine_connector/proc/destroy_connected_machine()
+	SIGNAL_HANDLER
+
 	disconnect_connector()
 	SSair.stop_processing_machine(connected_machine)
 	unregister_from_machine()
-	connected_machine = null
-	QDEL_NULL(gas_connector)
 	qdel(src)
 
 /**

code/modules/atmospherics/machinery/pipes/pipes.dm

@@ -35,7 +35,12 @@
 		AddElement(/datum/element/undertile, TRAIT_T_RAY_VISIBLE) //if changing this, change the subtypes RemoveElements too, because thats how bespoke works
 
 /obj/machinery/atmospherics/pipe/on_deconstruction(disassembled)
-	releaseAirToTurf()
+	//we delete the parent here so it initializes air_temporary for us. See /datum/pipeline/Destroy() which calls temporarily_store_air()
+	QDEL_NULL(parent)
+
+	if(air_temporary)
+		var/turf/T = loc
+		T.assume_air(air_temporary)
 
 	return ..()
 
@@ -61,11 +66,6 @@
 	replace_pipenet(parent, new /datum/pipeline)
 	return list(parent)
 
-/obj/machinery/atmospherics/pipe/proc/releaseAirToTurf()
-	if(air_temporary)
-		var/turf/T = loc
-		T.assume_air(air_temporary)
-
 /obj/machinery/atmospherics/pipe/return_air()
 	if(air_temporary)
 		return air_temporary