[2.0.8] Recipe Quality

[Anachrony]

TL;DR

Improve customizability of how modded recipes interact with the new Quality system.

What ?

Add new quality related fields to LuaRecipePrototype allowing greater customizability of Quality system on a per recipe basis.
Add a minimum_quality field to ItemIngredientPrototype. Below this doesn't qualify for the recipe. This is the baseline, so only quality above this level adds to the quality of the result.
Add a quality_weight field to ItemIngredientPrototype. If set then the quality of this ingredient has more or less impact relative to other ingredients on the overall result quality.
Add a quality_bonus field to ItemProductPrototype. If set this output of the recipe has a higher quality baseline. This isn't random and doesn't have a chance of resulting in even higher quality tiers.

Why ?

Right now the behavior of the Quality system seems very hard coded with limited flexibility for modding. The built-in assumptions make sense for the design philosophy of vanilla Factorio, but can be an awkward fit for mods which often have more tiers of the same type of items than vanilla, and alternate recipes for the same product. There is potential in some cases for such mods to consolidate some of the different tiers of items into different qualities of items instead. But for this to make sense they may require a little more customization in how quality works.

[benlove007]

I would be particularly interested in this feature.

The holmium-solution recipe requires 2 holmium-ore, 1 stone, and 10 water. By default, holmium-ore is not used for anything else. So, if I have higher quality holmium-ore (whether intentionally or not), the only way to consume it is to create holmium-solution, which will require a corresponding higher quality stone unit. However, because holmium-solution is a fluid, it lacks quality tiers itself. And the resultant 100 units of holmium-solution is the same regardless of the input quality. This means that higher quality holmium-ore is strictly negative: the result of the holmium-solution recipe is the same, but it now requires a higher quality stone unit as well.

I would like to be able to create a mod to add "higher quality" holmium-solution recipes: the inputs would be the same, but the output would be some percentage greater quantity holmium-solution, so that there's a natural benefit to higher quality holmium-ore. However, I cannot do this now because recipes do not allow specifying input quality in order to differentiate outputs.

[protocol_1903]

This has already been discussed at length in the FFFs and related posts here and elsewhere why quality cannot be applied to recipes in such a way. This won't be implemented because it presents many engine optimization and edge case exploits surrounding productivity.