Fix out of bounds in lighting subsystem (#75018)

## About The Pull Request
Fixes #74697

Look at this for loop

bfba2c5934/code/controllers/subsystem/lighting.dm (L34-L39)

Now look at update corners

bfba2c5934/code/modules/lighting/lighting_source.dm (L428-L430)

Now look at refresh values. this proc has a chance to delete itself here

bfba2c5934/code/modules/lighting/lighting_source.dm (L315-L318)
And here

bfba2c5934/code/modules/lighting/lighting_source.dm (L331-L334)

Now look at the Destroy proc, specifically focus on the needs_update
condition

bfba2c5934/code/modules/lighting/lighting_source.dm (L66-L67)

We are removing the light from the subsystem source queue while the
subsystem is still iterating through them causing big problems for this
for loop

bfba2c5934/code/controllers/subsystem/lighting.dm (L33-L37)

which causes the out of bounds exception because loop variable `i` is
not updated accordingly when this list size is reduced mid iteration.

The solution? we have to move the loop variable `i` back whenever the
source is deleted i.e. removed from the list so we don't overflow

## Changelog

🆑
fix: out of bounds when updating lights in lighting subsystem
/🆑

---------

Co-authored-by: LemonInTheDark <58055496+LemonInTheDark@users.noreply.github.com>
This commit is contained in:
SyncIt21
2023-05-24 23:59:56 +05:30
committed by GitHub
parent fd777c6375
commit cd4ed228f2
2 changed files with 58 additions and 41 deletions

View File

@@ -434,28 +434,20 @@
var/list/datum/lighting_corner/new_corners = (corners - src.effect_str)
LAZYINITLIST(src.effect_str)
var/list/effect_str = src.effect_str
if (needs_update == LIGHTING_VIS_UPDATE)
for (var/datum/lighting_corner/corner as anything in new_corners)
for (var/datum/lighting_corner/corner as anything in new_corners)
APPLY_CORNER(corner)
if (. != 0)
LAZYADD(corner.affecting, src)
effect_str[corner] = .
// New corners are a subset of corners. so if they're both the same length, there are NO old corners!
if(needs_update != LIGHTING_VIS_UPDATE && length(corners) != length(new_corners))
for (var/datum/lighting_corner/corner as anything in corners - new_corners) // Existing corners
APPLY_CORNER(corner)
if (. != 0)
LAZYADD(corner.affecting, src)
effect_str[corner] = .
else
for (var/datum/lighting_corner/corner as anything in new_corners)
APPLY_CORNER(corner)
if (. != 0)
LAZYADD(corner.affecting, src)
effect_str[corner] = .
// New corners are a subset of corners. so if they're both the same length, there are NO old corners!
if(length(corners) != length(new_corners))
for (var/datum/lighting_corner/corner as anything in corners - new_corners) // Existing corners
APPLY_CORNER(corner)
if (. != 0)
effect_str[corner] = .
else
LAZYREMOVE(corner.affecting, src)
effect_str -= corner
else
LAZYREMOVE(corner.affecting, src)
effect_str -= corner
var/list/datum/lighting_corner/gone_corners = effect_str - corners
for (var/datum/lighting_corner/corner as anything in gone_corners)