Saving a list with "" in it writes it as null

ID:2918495
 
Mar 26 2024, 8:35 pm (Edited on Mar 26 2024, 8:45 pm)
Resolved
Blank strings were being saved in savefiles as null values.
BYOND Version:515.1633
Operating System:Windows 10 Pro 64-bit
Web Browser:Chrome 123.0.0.0
Applies to:Dream Daemon
Status: Resolved (515.1634)
This issue has been resolved.
Descriptive Problem Summary:

When saving a list that has a blank string (""), it's rewritten as null. I can only imagine this has to do with the savefile changes brought on by 515.

515 is capable of loading a savefile that has, for example, list("") in it and loads it correctly. It just writes null in place of "" when writing a list.

I'm going to provide a code snippet. You can demonstrate the problem by performing the "savetest" verb, then the "loadandtest" verb.

You can observe the differences in the write functionality between 514 and 515 by performing the "savetest" verb on 514 and performing the "loadandtest" verb on 515.

Code Snippet (if applicable) to Reproduce Problem:
obj/myObj
    var/list/blankStringList = list("")

proc/save()
    var/obj/myObj/initialObject = new
    var/savefile/S = new("test.sav")
    S["Thing"] << initialObject
    world<<"BYOND ver [world.byond_version]: saved to test.sav"

proc/load()
    var/savefile/S = new("test.sav")
    var/obj/myObj/differentObject
    S["Thing"] >> differentObject
    if(differentObject.blankStringList[1] == "")
        world<<"BYOND ver [world.byond_version]: blank string"
    else
        world<<"BYOND ver [world.byond_version]: null"

mob/verb/savetest()
    save()

mob/verb/loadandtest()
    load()


Expected Results:
"BYOND ver 515: blank string"

Savefile contents:
Thing = object(".0")
    .0
        type = /obj/myObj
        blankStringList = list("")


Actual Results:
"BYOND ver 515: null"

Savefile contents:
Thing = object(".0")
    .0
        type = /obj/myObj
        blankStringList = list(null)


Did the problem NOT occur in any earlier versions? If so, what was the last version that worked?
Explained above.
Mar 26 2024, 8:38 pm
I also went ahead and tested this against an associative list. It'll also write blank-string values as null, not just keys.

obj/myObj
    var/list/blankStringList = list("" = "")

proc/save()
    var/obj/myObj/initialObject = new
    var/savefile/S = new("test.sav")
    S["Thing"] << initialObject
    world<<"BYOND ver [world.byond_version]: saved to test.sav"

mob/verb/savetest()
    save()


Savefile contents:
Thing = object(".0")
    .0
        type = /obj/myObj
        blankStringList = list(null = null)

Mar 27 2024, 10:44 am
Lummox JR resolved issue with message:
Blank strings were being saved in savefiles as null values.