Runtime - writing to read-only variable

ID:1774884
 
Jan 31 2015, 3:58 pm
Resolved
BYOND Version:506
Operating System:Windows 7 Pro
Web Browser:Firefox 31.0
Applies to:Dream Daemon
Status: Resolved
This issue has been resolved.
While testing some stuff locally a completely unrelated and unaltered object and file spat out runtimes on world start about writing to a read only variable. The live server running the code has never had this occur.

runtime error: writing to read-only variable
proc name:
  source file: supermatter.dm,68
  usr: null
  src: Supermatter Shard (/obj/machinery/power/supermatter/shard)
  call stack:
Supermatter Shard (/obj/machinery/power/supermatter/shard): ()
Supermatter Shard Crate (/obj/structure/closet/crate/secure/large/reinforced/shard): New(the floor (100,59,1) (/turf/simulated/floor))


--Starting source--
/obj/structure/closet/crate/secure/large/reinforced/shard
    name = "Supermatter Shard Crate"
    New()
        ..()
        sleep(2)
        new /obj/machinery/power/supermatter/shard(src)


supermatter.dm
line 68 doesn't even point to a read only variable.
Jan 31 2015, 4:12 pm
related id:1613720
Jan 31 2015, 6:10 pm
I don't believe this is related since locally I haven't added any new procs just have been trying to figure out an unrelated bug.
Jan 31 2015, 6:12 pm
Mostly related because of the error it suggests:

runtime error: writing to read-only variable

One would think they'd have the same circumstances due to it being SS13.
Jan 31 2015, 7:02 pm
Fair enough.
Feb 1 2015, 6:22 am
Seems this runtime goes away with 507 which is why ive not seen it on the live server. I guess i downgraded my local client to 506 for some reason and thought i was still on 507.
Feb 1 2015, 6:25 am
This one looks like it's screwing with the VM at runtime (instruction stream corruption?), since the following logs show random garbage errors soon after this one.

Examples (courtesy of Angelite)
[...] indicates expected debug output (regarding the database, jukebox, genetics, and instance profiling).
[END] indicates end of log: dream daemon crashed at this point.

[...]
runtime error: writing to read-only variable
proc name:
source file: supermatter.dm,68
usr: null
src: Supermatter Shard (/obj/machinery/power/supermatter/shard)
call stack:
Supermatter Shard (/obj/machinery/power/supermatter/shard): ()
Supermatter Shard Crate (/obj/structure/closet/crate/secure/large/reinforced/shard): New(the floor (100,59,1) (/turf/simulated/floor))
[...]
runtime error: BYOND Error: bad instruction: 318
proc name: follow tube (/obj/structure/transit_tube_pod/proc/follow_tube)
source file: transit_tubes.dm,317
usr: null
src: the transit tube pod (/obj/structure/transit_tube_pod)
call stack:
[END]



[...]
runtime error: writing to read-only variable
proc name:
source file: supermatter.dm,68
usr: null
src: Supermatter Shard (/obj/machinery/power/supermatter/shard)
call stack:
Supermatter Shard (/obj/machinery/power/supermatter/shard): ()
Supermatter Shard (/datum/supply_packs/supermatter_shard): New()
supply shuttle (/datum/controller/process/supplyShuttle): setup()
/datum/controller/processSched... (/datum/controller/processScheduler): addProcess(supply shuttle (/datum/controller/process/supplyShuttle))
/datum/controller/processSched... (/datum/controller/processScheduler): setup()
: New()
[...]
runtime error: Cannot read null.turf
proc name: Del (/atom/movable/Del)
source file: atoms_movable.dm,49
usr: null
src:
call stack:
Del()
/datum/effect/effect/system/tr... (/datum/effect/effect/system/trail/space_trail): start()
the floor (177,118,1) (/turf/simulated/floor): build lighting area("/area/science/roboticssd_L5#0f...", 5, 2)
the floor (177,118,1) (/turf/simulated/floor): shift to subarea()
lighting (/datum/controller/process/lighting): doWork()
lighting (/datum/controller/process/lighting): process()
/datum/controller/processSched... (/datum/controller/processScheduler): runProcess(lighting (/datum/controller/process/lighting))
[END]

Here's the (ir)relevant section of supermatter.dm (line numbers on left):

 [...]
15 | /obj/machinery/power/supermatter
16 |     name = "Supermatter Crystal"
 [...]
67 |     //Add types to this list so it doesn't make a message or get desroyed by the Supermatter on touch.
68 |     var/list/message_exclusions = list(/obj/effect/effect/sparks)

As you can see, the var shouldn't be read-only, and that's the final line in the definition (the following section defines the .../shard subtype).

Angelite reported that upgrading to BYOND version 507 resolved the issue.

May be related to this bug as well:
http://www.byond.com/forum/?post=1704068
(cause still unknown, likely due to some internal compiler limitations fixed by Lummox in 507).
Feb 13 2015, 5:32 am
Lummox JR resolved issue