Removing Variables from Item Def/Definitions

[TubberPupper]

Problem

Sorry if this is a duplicate or isn't formatted properly. I looked for a tiny bit to see if there was a thread opened by appgurueu but I couldn't find one, and this is my first time using GitHub

A thread I opened a few weeks ago https://forum.minetest.net/viewtopic.php?t=30405 went into detail about how to remove functions from an Item's definition. Was told I should open an issue about it by LMD aka @appgurueu :D

There is no official engine function or way (to my knowledge) to remove an unwanted variable - such as "on_use" in this case. Currently I set it to false as a method of committing to this - but this isn't an officially supported way of doing such.

Solutions

Two solutions were proposed by appgurueu and with comments by @Montandalar (BlockHead)

appgurueu's solutions:

I think we should have a way to let override_item delete fields, that definitely seems like a legitimate feature to me. One way to implement this could be using a special, unique minetest.nil_placeholder (could be a userdatum) which could be used instead of false (the problem with false is that it does not work for fields which support booleans; for other fields it's fine however). Or adding another parameter with a list of fields to be deleted?

Montandalar's comment;

I think I like the delete-list better because it extends the API with an extra argument - of course, there may be weird code out there using an extra argument already, because you should expect the unexpected, but that's not really a supported use case. I like the delete-list because doesn't have a magic userdata* value which is probably what would be needed, and also would not be present in older versions whereas the delete-list would pass through and basically be ignored. I suppose that makes it a question of crash vs no crash for a bit of code that doesn't check for compatibility of what it is about to use.

The probably best solution would be to go with the second solution that appgurueu suggested: another parameter - a table of indexes to be removed. But I imagine both solutions could work out just as well?

Alternatives

Well as I mention in the problem, I currently use "false" as a way to modify a function variable so that it is not used.

Additional context

Just be sure to check https://forum.minetest.net/viewtopic.php?t=30405 for anything extra :D