Ambiguity in LivingEntity.getRemoveWhenFarAway() documentation

[kacpermajkowski]

Expected behavior

LivingEntity.getRemoveWhenFarAway() returns false for Cow, false nametagged Zombie, true for regular Zombie

Since the documentation states:

"Returns if the living entity despawns when away from players or not.
By default, animals are not removed while other mobs are.

Returns:
true if the living entity is removed when away from players"

then it follows that for any entity that keeps existing after all players are farther than 128 blocks the method returns false, otherwise true.

Observed/Actual behavior

LivingEntity.getRemoveWhenFarAway() returns 'true' for Cow, 'true' for regular Zombie

So the logical conclusion I pointed out in expected behaviour section is not met.

Steps/models to reproduce

use LivingEntity.getRemoveWhenFarAway() in any context e.g. EntityMoveEvent and test on Cow and Zombie.

Plugin and Datapack List

datapack list
[22:17:45 INFO]: There are 3 data pack(s) enabled: [vanilla (built-in)], [file/bukkit (world)], [paper (built-in)]
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plugins
[22:17:47 INFO]: ℹ Server Plugins (7):
[22:17:47 INFO]: Bukkit Plugins:
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Paper version

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Other

Please fix the way function works, or add another function with similar functionality to the one expected and document behavior of this one really well.

[Lulu13022002]

I think the javadoc is just super outdated here, for record the original impl removed the removeWhenFarAway check: 4dadf0e and the method got mangled later since MC evolved around. So I think the way to go is to rename that method to better describe what it does, I'm not sure however if similar functionality can be exposed here.

[kacpermajkowski]

Currently I'm using this function, but I'm not really familiar with NMS and I'm not sure if this covers all the bases as to what makes the mob "despawnable". From my limited testing it correctly distinguishes between a Zombie, a Cow, an Axolotl and a named Axolotl.

    private boolean isNmsMobDespawnable(Mob nms) {
        return !nms.persistenceRequired &&
                !nms.requiresCustomPersistence() &&
                !nms.getType().getCategory().isPersistent();
    }