Merge pull request #4984 from Citadel-Station-13/upstream-merge-34485

[MIRROR] Couple of chemistry fixes

code/modules/reagents/chemistry/holder.dm

@@ -158,7 +158,7 @@
 	if(istype(target, /datum/reagents))
 		R = target
 	else
-		if(!target.reagents || src.total_volume<=0)
+		if(!target.reagents)
 			return
 		R = target.reagents
 	amount = min(min(amount, src.total_volume), R.maximum_volume-R.total_volume)
@@ -181,14 +181,14 @@
 
 /datum/reagents/proc/copy_to(obj/target, amount=1, multiplier=1, preserve_data=1)
 	var/list/cached_reagents = reagent_list
-	if(!target)
+	if(!target || !total_volume)
 		return
 
 	var/datum/reagents/R
 	if(istype(target, /datum/reagents))
 		R = target
 	else
-		if(!target.reagents || src.total_volume<=0)
+		if(!target.reagents)
 			return
 		R = target.reagents
 

code/modules/reagents/chemistry/reagents/pyrotechnic_reagents.dm

@@ -187,7 +187,7 @@
 /datum/reagent/cryostylane/on_mob_life(mob/living/M) //TODO: code freezing into an ice cube
 	if(M.reagents.has_reagent("oxygen"))
 		M.reagents.remove_reagent("oxygen", 0.5)
-		M.bodytemperature -= 15
+		M.bodytemperature = max(M.bodytemperature - 15,0)
 	..()
 
 /datum/reagent/cryostylane/reaction_turf(turf/T, reac_volume)

code/modules/reagents/chemistry/recipes/pyrotechnics.dm

@@ -346,15 +346,17 @@
 	id = "cryostylane_oxygen"
 	results = list("cryostylane" = 1)
 	required_reagents = list("cryostylane" = 1, "oxygen" = 1)
+	mob_react = FALSE
 
 /datum/chemical_reaction/cryostylane_oxygen/on_reaction(datum/reagents/holder, created_volume)
-	holder.chem_temp -= 10*created_volume
+	holder.chem_temp = max(holder.chem_temp - 10*created_volume,0)
 
 /datum/chemical_reaction/pyrosium_oxygen
 	name = "ephemeral pyrosium reaction"
 	id = "pyrosium_oxygen"
 	results = list("pyrosium" = 1)
 	required_reagents = list("pyrosium" = 1, "oxygen" = 1)
+	mob_react = FALSE
 
 /datum/chemical_reaction/pyrosium_oxygen/on_reaction(datum/reagents/holder, created_volume)
 	holder.chem_temp += 10*created_volume