Safely propagating sciences through the tech tree

[Frontrider]

Sometimes we want to get a science pack to pass through to future research. But, this creates issues depending on how the tech tree ends up being, it can create cases when an entire branch or the whole tree becomes impossible to progress with.

These are any mods that don't let you import that science pack until a certain point, or want you to use a lab that can't have that science (the game will crash during load in this case).

Solution from: @SimonBrodtmann :
Build a new tree from the sciences as you propagate the pack.
Problem:
There is exactly no way to tell if the other mod was intended to be beatable with your science packs, or if the game won't crash from it. I think We could try to look for like all vanilla sciences but that is still not a good condition.

My solution:

• Mark the science pack's technology with a flag that has the pack's name in it. (so we don't need to figure out what science we're unlocking from the effects that it has). If we find this flag, we propagate the science from here.
• Mark technologies where we don't want to propagate the packs with something to let the mod protect itself from sciences it may not be able to access. I expect these to be planet discoveries. (cerys and maraxsis will use these flags, I can see metal and stars use this flag once it becomes its own solar system)
• Maybe allow for a whitelist, in case you know that your mod won't break from another one.

When a flagged technology is found we no longer push new science packs beyond it. There will be a point when they merge back together again, but essential sciences can be protected.
This one goes directly against it being an opt-in feature but I also don't see a way for it to be like that without flagging every single technology that exists in the game.
At least you can know which mod is doing it.

[Frontrider]

From @SimonBrodtmann

About the incompatibility: As the author of a mod that adds science packs to many technologies, I feel responsible if I break something with it and I'm willing to add compatibility code to make it work again. If someone reaches out to me or I find the problem myself, I'll gladly do that. If the mod combination makes sense at least. I also added instructions in the description for other mod authors to do that for me if they prefer that.

You taking responsibility and marking the technologies with those "gates" also works for me (whatever api it lands on). Until it becomes more pressing. :) This simplifies the compatibility code on your side, while letting the other mod take it as-is when the need arises.
This also lets other mods to preemptively protect themselves as well so we cover both of those options. Neither of them are exclusive to each other.

I think Muluna also does this or may want to to it to a degree. I need to check deeper, Tenebris and maraxsis also does some of this by hand.

I know that Lignumis is not the standard case as most other planets. That could be a reason that I need to do a little bit more manual work than other mod authors to create compatibility. If a generic solution doesn't cover all use cases, that's totally fine. That doesn't mean, compatibility is not possible. Currently I'm doing a run with almost all planets enabled to get a picture on how the planets combine.

Both the "I don't want new packs" and "I want everything to go forward" are valid.
I also want to do exactly the same, the only difference from you is that I come into the picture later.

Any mod not having to manually forward sciences to technologies coming after is useful.

[SimonBrodtmann]

Can't we define "I don't want new packs" and "I want everything to go forward" in the PlanetPrototype? Maybe also define the names of the science packs belonging to the planet and somehow mark the technology name(s) where the "I want everything to go forward" starts?
Alternatively, define all that stuff by calling some function from this library.

[Frontrider]

Can't we define "I don't want new packs" and "I want everything to go forward" in the PlanetPrototype? Maybe also define the names of the science packs belonging to the planet and somehow mark the technology name(s) where the "I want everything to go forward" starts? Alternatively, define all that stuff by calling some function from this library.

I'd stick with the technologies themselves. It will usually be a planet discovery, but I'd rather leave it open instead of locking it into something that is not directly related.

[Frontrider]

The live example on why it has to be the technology. A lot of that clearly does not want any of the other sciences, but have a dependency on something that may propagate them forward.

[Frontrider]

Looking at more things, another approach:
Have a convention to "partition" the tech tree.

Two options that I can see:

• one string flag, since we can't read which mod a tech is coming from it will probably be that. You can pick your compatibility method based on what you read.
• tech group and subgroup like items/recipes. The group can still be the mod, but the subgroup can partition for planets, stages in progression etc.

This provides info for any other mod's code to automatically include additional sciences, without needing to know what the other mod is doing, while if you do things by hand you get a guide on what the other modder was thinking.
If the fields are missing, handle it as if it was in the base system.

With both approaches, the ensure_all_packs_from_vanilla_lab flag becomes a group on its own.

I don't think we will or need to, but we can also partition the vanilla tree for it.

I'm gonna give my perspective from dea dia on the second approach:

The mod's name can tell lignumus that these technologies may include the wooden science as wood is available, but NOT the steam science as gold is completely inaccessible.

Muluna can check the subgroup, and include the interstellar pack on the techs that belong to the gas giant as that is roughly that level that can have it.

With the second one planetslib can also include api methods that return the technologies that match a group or a subgroup. This type of partitioning does not matter for mods that take place on 1 surface as all items will be easy to access so it can fit in with planetslib.

@SimonBrodtmann @nicholasgower @danielmartin0

[nicholasgower]

My approach to adding interstellar technologies is manual, and I highly doubt it's possible to automate it in a way that's not over or under sensitive. I believe interstellar technologies have one of the following characteristics:

• Is a planet discovery technology for a location that can be considered an Aquilo-tier location.
• Is a technology that allows the creation of more interesting space platforms.

I highly doubt it's possible to automatically find technologies that meet these conditions. For that reason, I plan to only manually apply the science pack to technologies I think deserve it.

The code that does this is linked below.

https://github.com/nicholasgower/planet-muluna/blob/main/prototypes%2Ftechnology%2Finterstellar-technologies.lua

[Frontrider]

My approach to adding interstellar technologies is manual, and I highly doubt it's possible to automate it in a way that's not over or under sensitive.

I agree with this, but the goal is just to be "good enough". It IS very likely to be under sensitive if you spread a lot of science, which is good thing in my view. Less chances to cause problems.
The oversensitivity is also not an issue in my eyes too, because you either break the entire zone or not, so it will be very obvious.

Also the two approaches are not mutually exclusive.