"runtime error: Cannot read null.icon_size" when accessing world.icon_size

ID:2188467
 
Dec 19 2016, 12:54 am (Edited on Dec 19 2016, 1:00 am)
Resolved
BYOND Version:510
Operating System:Windows 7 Ultimate 64-bit
Web Browser:Chrome 56.0.2924.28
Applies to:Dream Daemon
Status: Resolved
This issue has been resolved.
Descriptive Problem Summary:
runtime error: Cannot read null.icon_size
proc name: update o (/obj/screen/parallax_layer/proc/update_o)
  source file: parallax.dm,247


/obj/screen/parallax_layer/proc/update_o(view = world.view)
    var/list/new_overlays = list()
    var/count = Ceiling(view/480/world.icon_size) //<--- line 247
    for(var/x in -count to count)
        for(var/y in -count to count)
            if(x == 0 && y == 0)
                continue
            var/image/I = image(icon, null, icon_state)
            I.transform = matrix(1, 0, x*480, 0, 1, y*480)
            new_overlays += I

    overlays = new_overlays
    view_sized = view
/proc/Ceiling(x, y=1)
    return -round(-x / y) * y


I'm just gonna make a guess here, world is not suppose to be null.

Happens after world init, so it's not that, Happens in 510 and 511.1366 (with a clean compile between testing)

If I had to take a guess, it's the default arg in the proc being a world dot access. I remember there being a bug around reference dot accesses and default args.
Dec 19 2016, 1:18 am
changing it to this made the bug go away:

/obj/screen/parallax_layer/proc/update_o(view)
    if (!view)
        view = world.view
    var/list/new_overlays = list()
    var/count = Ceiling(view/480/world.icon_size)
    for(var/x in -count to count)
        for(var/y in -count to count)
            if(x == 0 && y == 0)
                continue
            var/image/I = image(icon, null, icon_state)
            I.transform = matrix(1, 0, x*480, 0, 1, y*480)
            new_overlays += I

    overlays = new_overlays
    view_sized = view
Dec 19 2016, 9:22 am
Yep, it's that default arg bug again. Since I can't remember what thread that is, I'll just close this as resolved (even though the overall problem is not) so it doesn't clutter up the bug reports.
Dec 19 2016, 9:22 am
Lummox JR resolved issue
Aug 26 2017, 8:13 pm
Clutter.

Interesting workaround:

Add(mob/target,time=world.time)
    if(world.time-time>duration) //this line will runtime, as world is null somehow...
        return 0



Add(mob/target,time=world.time)
    set hidden = 0 //inserting a pointless setting will cause the runtime to no longer happen
    if(world.time-time>duration)