New versions, save compatibility, and set new variables to 0

[Zeroized]

Greetings, and thanks for your earlier help.
I've fixed most of my issues with Ren'py and Python, tumbling around, doing stuff. I've made some demos and I've ended pretty satisfied with the final result.
I've decided to build an episodic game, and release new content every month or so. But then I realized that every new build will have new variables, rendering the old saves useless. Since the inability to use saves in between versions could be a dealbreaker, I'm wondering if there is any way to check if there are new variables running when you load a game, and if those variables aren't defined, set them to 0 to avoid "variable non-defined" errors.

[PyTom]

Yes, you do:

Code: Select all

label after_load:
     $ store.newvar = getattr(store, "newvar", 0)
     return

There are other ways to test for presence/absence, so take this as mostly a guideline.

[Zeroized]

Thanks for the answer.
Where do I add this, though? And I assume "newvar" is the name of the new variable. Do I need to check for every new variable added?