Plugin remapping not working at all in 1.21.9

[Budderman18]

Expected behavior

Plugins remap to allow for nms usage

Observed/Actual behavior

No remapping is occuring

Steps/models to reproduce

1. run a server with a plugin using nms
2. various errors depending on what classes you use

Plugin and Datapack List

AdvancedReplay, AntiCheatReplay, Apollo-Bukkit, BadlionClientModAPI, BedWars, Essentials, EssentialsDiscord, EssentialsGeoIP, floodgate, Geyser-Spigot, GriefPrevention, IngotAntiCheat, IngotBedrockTweaker, IngotBridges, IngotCommunications, IngotDuels, IngotEconomy, IngotFactions, IngotHub, IngotInsights, IngotKitPvP, IngotMinigamesAPI, IngotPlayerManager, IngotServerManager, IngotSkywars, IngotSpleefPlus, IngotSurvivalGames, IngotTNTWars, IngotTowerDefense, IngotVanillaTweaker, IngotWorldManager, JukeBox, Multiverse-Core, Multiverse-Inventories, Multiverse-Portals, NoteBlockAPI, ProtocolLib, UltraCosmetics, WorldEdit

Paper version

This server is running Paper version 1.21.9-47-main@21b4930 (2025-10-03T18:17:01Z) (Implementing API version 1.21.9-R0.1-SNAPSHOT)

Other

No response

[lynxplay]

Known issue, we released prior to spigot and had not yet had the time to check through reobf mappings patches.
Will land soonish.

[lynxplay]

To follow up, remapping is not needed for NMS usage.

All of the plugins failing simply are not providing native paper NMS modules but instead use spigot mappings.
While we will get to it, it'd be highly advised those plugins start publishing paper-native jars instead of relying on our remapping functionality which is not an indefinite addition to paper.

[MiniDigger]

see https://docs.papermc.io/paper/dev/userdev/#compiling-to-mojang-mappings on how to ship your plugins with mojang mappings

[Jannyboy11]

Author of a spigot-mapped plugin here. Will there ever be a paperweight-maven-plugin? It's the main reason why I haven't implemented a dedicated Paper compatibility module yet for my plugin. Specialsource's remapping is only implemented for Maven, not Gradle.

[Strokkur424]

It is very unlikely that there will ever be an official paperweight-userdev Maven plugin it is only a small part of a bigger plugin collection called paperweight, which handles much more internal tooling (including fork tooling). Maintaining a dedicated Maven version is nothing that makes a lot of sense, as none of the PaperMC projects use Maven. This is similar to the modded environment, which is also focused on Gradle.

I recommend discussing and seeking help for Maven/Gradle migration and similar in our Discord server, since discussions like this over GitHub PR comments are not super great.

[MiniDigger]

the team doesn't have the capability to support two different build systems. paperweight-userdev is easier to maintain since it builds on paperweight-core, which we use in paper itself.
there is a community maintained maven plugin you could try out, but we obviously cant recommend that. I dont know how the special source maven plugin works, but special source is a standalone tool, running it in gradle should be easier than porting paperweight to maven.
something else to consider is if the maintenance burden on your part is worth it for an increasingly shrinking user share. in your case, looking at your bstats, 93% of servers using your plugin are running in a mojang mapped environment. which means that 93% of your users have slower server startup and doubled storage requirements just because you support the 7% (that, if our analytics are to be trusted, are more likely to run on old versions anyways).