[Feature Request] Apply multiple patches to a title

[ViridianViridian]

Currently, the only way to have Luma load multiple patches is to combine them into a single file. While there are tools for this, it can be inconvenient when dealing with many mods (in particular, there isn't really a way to remove or update a particular mod from the combined file without completely starting over).

Instead of checking for a single code.ips, Luma could check for all .ips files in a subdirectory and apply them one at a time in alphabetical order by filename. I expect this would cause a bit of a performance hit on startup, but the ease of use would be a worthwhile trade-off for most users, especially since the option to merge the patch files beforehand still exists.

[Dimensional]

There are some things to consider. Merging patches ahead of time would provide a means of making sure there is no conflict between them. Patches that overwrite the same data for example, or a patch that expands the data and causes another patch to write to the now-incorrect address. These are things that would require additional work for the end user to get them to load in a specific order, much like the load order for mods for Oblivion.

[ViridianViridian]

This is true, either way the onus is on the user to make sure mods are compatible. I think things like load order would be easier to keep track of when the files aren't "merged" until runtime, since (with the implementation I'm proposing here) you can just prepend a number to the filename like 01_patchxyz.ips. Merging ahead of time, once you have the file you have to remember what order you put the patches in, and possibly have to investigate how the tool handles conflicts if it's not documented.

I think it's also important to remember that Luma's approach to game patching (just drag and drop a few files and you're done) is so accessible that it brings a lot of users who aren't very confident about "technical" stuff. For those users, asking them to download an external tool, possibly figure out the command line for the first time, and have to repeat the entire process whenever one of their mods updates, is not that far off from asking them to just dump their ROM and apply patches manually, and they probably just won't attempt either option.
I've seen some evidence of this with a modder distributing their patch pre-merged with my (totally unrelated) mod, assuming most users would want both and not wanting to have to walk them through the process of merging patches (I have no problem with them redistributing my mod, but I worry this sort of thing will lead to mod conflict hell in the long-term).

Basically, I agree what I'm proposing is an imperfect solution, but I think it's far less imperfect than the workarounds people will end up using otherwise.

[ViridianViridian]

Also, if there's any interest in this feature from the maintainers, I am willing to try implementing it; I spent a lot of time staring at the loader code while working on #2170.

[TuxSH]

I'm a bit ambivalent about this. Is there precedent?

[ViridianViridian]

I'd say there's already precedent in Luma in that you can easily combine mods that edit RomFs just by copying over the files from both (as long as they don't conflict).

Other than that, I don't know how any other consoles' homebrew software handles patches, but in terms of user experience this is pretty close to how most PC game mod loaders I've used work: you just add mods and set the load order, and the rest is handled for you (except dealing with conflicts). Not sure if that's the kind of precedent you mean, though?