ios - Strange-random crash on SKNode addChild -

i have simple class func adding skemitternode on many different occasions.

i cannot reproduce steps when exception occurs. happens , quite randomly. can call method 500 times without error or in cases error can happen after 1 or 2 call, etc.

the problem/exception line is:

root?.addchild(sparks)

below method , stack trace. have no idea how debug this. i've tried many different things without success.

any ideas ?

class func setsimplesparkseffect(root:sknode?, color:uicolor, position:cgpoint) {     if cgpointequaltopoint(position, cgpointzero)     {         return     }      let sparks = skemitternode(filenamed: "simplesparks")     sparks.alpha = gameobjectsdefaultalpha     sparks.particlecolorsequence = nil     sparks.particlecolorblendfactor = 1.0     sparks.particlecolor = color     sparks.position = position     sparks.zposition = sparkselementszposition      root?.addchild(sparks)     sparks.runaction(skaction.waitforduration(nstimeinterval(emmitersimpleshortduration)), completion: { () -> void in          sparks.runaction(skaction.fadeoutwithduration(nstimeinterval(factorsparksfadeoutduration)), completion: { () -> void in              sparks.removeallactions()             sparks.removeallchildren()             sparks.removefromparent()          })      }) } 

and stack trace:

thread : crashed: com.apple.main-thread 0  libc++abi.dylib                0x0000000199944ce4 __dynamic_cast + 52 1  spritekit                      0x000000018ab63f58 __15-[sknode scene]_block_invoke + 60 2  spritekit                      0x000000018ab63f58 __15-[sknode scene]_block_invoke + 60 3  spritekit                      0x000000018ab28038 skcnode::walkup(void (skcnode*, bool*) block_pointer, bool) + 76 4  spritekit                      0x000000018ab63eac -[sknode scene] + 132 5  spritekit                      0x000000018ab643ac -[sknode insertchild:atindex:] + 356 6  spritekit                      0x000000018ab64224 -[sknode addchild:] + 76 7  dodgemaster                    0x00000001000f1d80 static dodgiecommon.setsimplesparkseffect(sknode?, color : uicolor, position : cgpoint) -> () (dodgiecommon.swift:275) 8  dodgemaster                    0x00000001000d2bc4 gamelevel.(gamelogicgoalerhitmecontact(gamelevel) -> (nsnotification) -> ()).(closure #1) (gamelevel.swift:502) 9  dodgemaster                    0x0000000100125018 static helper.(runasynconmain(helper.type) -> (() -> ()) -> ()).(closure #1) (helper.swift:270) 10 dodgemaster                    0x00000001000b41c4 thunk (pointoser.swift) 11 libdispatch.dylib              0x000000019aa917b0 _dispatch_call_block_and_release + 24 12 libdispatch.dylib              0x000000019aa91770 _dispatch_client_callout + 16 13 libdispatch.dylib              0x000000019aa96e20 _dispatch_main_queue_callback_4cf + 1844 14 corefoundation                 0x000000018574c258 __cfrunloop_is_servicing_the_main_dispatch_queue__ + 12 15 corefoundation                 0x000000018574a0c0 __cfrunlooprun + 1628 16 corefoundation                 0x0000000185678dc0 cfrunlooprunspecific + 384 17 graphicsservices               0x00000001907cc088 gseventrunmodal + 180 18 uikit                          0x000000018ad52f60 uiapplicationmain + 204 19 dodgemaster                    0x000000010011de24 main (appdelegate.swift:22) 20 libdyld.dylib                  0x000000019aac28b8 start + 4 

another person on here had similar problem think may encountering too... i've tailored response on post yours.

let sparksfile: string = nsbundle.mainbundle().pathforresource("simplesparks", oftype: "sks")! let sparks = nskeyedunarchiver.unarchiveobjectwithfile(explosionfile) as! skemitternode sparks.alpha = gameobjectsdefaultalpha sparks.particlecolorsequence = nil sparks.particlecolorblendfactor = 1.0 sparks.particlecolor = color sparks.position = position sparks.zposition = sparkselementszposition  self.root?.addchild(sparks)