[bug] define not changing the saved variable

[Victorius]

So I've encountered a bug (I think it is, according to docs). I assigned a variable as

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 default x = "some value"

, then I saved the game. In later game version I've changed the code to

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define x = "some other value"

after loading the game x was "some value" so it didn't change. At first I've thought it was supposed to work like this, but later I've read docs about define & default, according to docs it should be changed.

Ren'Py version: 7.4.2.1292

[Victorius]

It also works like that with assigning variable inside of a label.

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$x = "some var"

and then removing it and adding

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define x = "some other var"

[zmook]

I can't find code or documentation that says for sure, but I think the problem is that init-time code (like define statements) is executed before the save is loaded. Then the value of the variable read in from the save file overwrites the init (defined) value, just like what would happen if you had

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define a = 1

label start:
    $ a = 2 

`Defines` sound like they should be constants but they're not; they are recorded in the store just like any other variable and can be changed later. The principal (only?) difference is that their values are assigned at init time and are not recorded in save files unless they're changed.

[zmook]

If you have a variable declared version 1 in a default,

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# v1
default a = 'hello'

and want to fix it in version 2 including retroactively to people playing from saves, I think you have to use the after_load label to correct it:

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# v2
default a = 'hi'

label after_load:
	$ a = 'hi'  	# to fix old saved values

It's kind of ugly and error-prone having to set the value in two places, though. Alternately, you could give up on the `default` statement altogether and do:

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# v2a
label set_defaults:
    if not hasattr(store, 'a') or a = 'hello':
        a = 'hi'
    return

label start:
    call set_defaults

label after_load:
    call set_defaults

Or, possibly best, just throw away the variable you need to change and replace it with a new one.

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# v2b
default a2 = 'hi'

eileen "[a2] there, fellow sprite!"

[_ticlock_]

This post does not exactly answer, but give an idea that saved variables overwrite the variables defined with define statements as zmook mentioned.
This problem should appear only when loading save file that stores the variable. Basically, it is a compatibility problem.

If you want to ensure that the value of the variable is correct for old save files you can explicitly check it in its value in the after_load label:

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label after_load:
    python:
        if x != "some other var":
            x = "some other var"

[Imperf3kt]

Is this because you wanted to use the variable you had chosen, for something else, or because you decided on a more appropriate variable name?

If the original variable is no longer in use, you can simply default the variable as the new variable.

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default new_variable = "some other variable"
default old_variable = new_variable

Make sure you default the new variable before the old one, so it exists when renpy tries to set a value to the old variable.

[Victorius]

Thanks for replies!

I've changed variable name to a new one, I had a list of enemies hard coded inside a label, to give modders ability to add new enemies without changing vanilla files I moved it outside of a label so they can append to it at init time. I've written about this because I thought it might be a bug, so I wanted to provide feedback.