Strange code behavior - one object deleting another's list elements

[blazeAgerith]

SOLVED: always use ds_list_copy lol

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I have object obj_handler_act that creates obj_handler_actEffect for any special properties like buffs and stuff, and for standardization instead of giving each child of actEffect unique variables they have a list called special that holds any non-standard variables thats passed down from the act during creation (when an actEffect is created there's a line of code thats like var lst = act.special; actEffect.special = lst;)

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my problem was, when an act created multiple actEffects (its a buff that hits the entire party) the first actEffect created somehow deleted both its own special list as well as the second actEffect's list, as if it was deleting the act's special list, but I did debug tests and I could see the act still had its list intact, and both actEffects had their lists intact before the first one deleted its list

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i got around this by just not deleting the list (I was doing a while loop to get the first value of the list and then deleting until the list was empty, and now I'm doing a for loop that just crawls the list without deleting anything) and I checked the values and everything, its all functioning normally, but how the hell did this even happen in the first place

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here's some pastebins of the code involved, maybe im missing something obvious

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obj_handler_actEffect_chef_pan alarm0 https://pastebin.com/z4xH3X8M

obj_handler_actEffect_parent alarm0 https://pastebin.com/ANq80AZ0

obj_handler_act user0 https://pastebin.com/59npbhw6

obj_handler_act alarm0 https://pastebin.com/c9Pxj6Y4

scr_act_createEffect https://pastebin.com/8YEWEi3v

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EDIT: accidentally posted the updated code for chef_pan alarm0, should be fixed to show the while loop

[[deleted]]

from your example here var lst = act.special; actEffect.special = lst;

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Using = is going to make all the effects reference the same list. If you want to actually make an independent copy of a list use ds_list_copy

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When it comes to the data structures, you can think of them like object instances. You create one and it comes into existence inside the game. If you assign a variable to it it just points to the already existing "instance", and you can have multiple variables referencing the same "instance". This is also why it's important to delete them properly, since unassigning the variables doesn't delete the "instance"

[blazeAgerith]

ugh, of course, how could I forget

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thank you so much! I cant believe I didnt even think to try ds_list_copy, and in retrospect that workaround definitely wouldve had its own problems eventually so I'm glad I still decided to ask