NoSuchMethodError on every cow death (Minecraft 26.2): Bukkit_v26_2 doesn't override getEntityMeta/setEntityMeta

[CruelWinter2]

Summary

Every cow death throws NoSuchMethodError on Minecraft 26.2, so the death is never logged and a stack trace is printed each time. 81 occurrences over four days on a normal survival server.

Versions

• CoreProtect 24.0 (dev build b92)
• Paper 26.2 (build 92, paper-api-26.2.build.92-stable)
• Java 25

Stack trace

[ERROR]: Could not pass event EntityDeathEvent to CoreProtect v24.0
java.lang.NoSuchMethodError: 'org.bukkit.entity.Cow$Variant org.bukkit.entity.AbstractCow.getVariant()'
    at net.coreprotect.bukkit.Bukkit_v1_21_5.getEntityMeta(Bukkit_v1_21_5.java:25)
    at net.coreprotect.listener.entity.EntityDeathListener.logEntityDeath(EntityDeathListener.java:560)
    at net.coreprotect.listener.entity.EntityDeathListener.onEntityDeath(EntityDeathListener.java:655)
    at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:71)

Reproduction

1. Run Paper 26.2
2. Kill any cow
3. Stack trace above; the death is not recorded in /co lookup

Chickens and pigs appear unaffected.

What seems to be happening

Bukkit_v26_2 extends Bukkit_v1_21_5 and overrides neither getEntityMeta nor setEntityMeta:

public class Bukkit_v26_2 extends Bukkit_v1_21_5 {
    public Bukkit_v26_2() { this.initializeBlockGroups(); }
    private void initializeBlockGroups() {
        BlockGroup.TRACK_TOP_BOTTOM.add(Material.SULFUR_SPIKE);
    }
}

So the inherited Bukkit_v1_21_5.getEntityMeta runs, and its cow.getVariant() call was compiled when getVariant()/setVariant() were declared on AbstractCow. On 26.2 those moved down to Cow, and AbstractCow is now an empty interface:

$ javap -p org/bukkit/entity/AbstractCow.class    # paper-api 26.2.build.92-stable
public interface org.bukkit.entity.AbstractCow extends org.bukkit.entity.Animals {
}

$ javap -p org/bukkit/entity/Cow.class
public interface org.bukkit.entity.Cow extends org.bukkit.entity.AbstractCow {
  public abstract org.bukkit.entity.Cow$Variant getVariant();
  public abstract void setVariant(org.bukkit.entity.Cow$Variant);
  ...
}

setEntityMeta has the same cow.setVariant(...) call, so rollbacks that restore a cow variant would presumably hit this too.

Something that argues against the above

I want to flag this clearly, because it suggests the explanation may be incomplete.

I tried patching Bukkit_v26_2 to override both methods, recompiled against paper-api 26.2.build.92-stable, and confirmed in the resulting bytecode that the call targets the new location:

15: invokeinterface #32,  1   // InterfaceMethod org/bukkit/entity/Cow.getVariant:()Lorg/bukkit/entity/Cow$Variant;

With that class in place the error persisted, unchanged, now attributed to my override's line rather than the inherited one — still naming AbstractCow.getVariant(), even though the compiled method contains no reference to AbstractCow at all.

Things I ruled out:

• Only one jar on the server contains net/coreprotect/ classes, so no duplicate/shaded copy
• The runtime paper-api is byte-identical to the one I compiled against (same md5), and declares getVariant() on Cow
• paper-api 26.1.2 also declares it on Cow, so a stale API on the classpath would not produce this message either
• No Paper remapped-plugin cache present

I reverted to the stock build and I'm not claiming to understand it. Someone familiar with how the Bukkit_vX adapters are selected and loaded will likely see the cause faster than I did — I'm reporting the crash and my observations rather than a confident diagnosis.