PassiveVindicatorMixin.java

@Mixin(VindicatorEntity.class)
public abstract class PassiveVindicatorMixin {
    @Redirect(
            // The method we want to manipulate
            method = "initGoals",
            at = @At(
                    /* We are redirecting the NEW opcode here. This just means we're going to
                       be returning a different object than the one that is normally returned.
                       The objects should be compatible, so we want to make sure we return a Goal. */
                    value = "NEW",

                    /* This is the class we are replacing. In this case, the FollowTargetGoal.
                       We are replacing the FollowTargetGoal because this is the goal that actually
                       tells the Vindicator "you should attack this entity". The attack goal only
                       uses this target once it's set by a FollowTargetGoal. */
                    target = "net/minecraft/entity/ai/goal/FollowTargetGoal",

                    /* There are three places where a new FollowTargetGoal is created in initGoals.
                       We only need to replace the one that's related to players, since this shouldn't
                       change the way vindicators react to merchants or iron golems. This will be the first
                       of the three. Ordinals are 0-indexed, so the first one is ordinal = 0. */
                    ordinal = 0
            )
    )
    // Our method needs to have the same signature as the
    private <T extends LivingEntity> FollowTargetGoal<T> replaceFollowPlayerGoal(MobEntity mobEntity, Class<T> clazz, boolean checkVisibility) {
        return new FollowTargetGoal<>(
                mobEntity,	// This is the vindicator entity. Originally passed to the constructor as `this`.
                clazz,		// The class that this goal should apply to. Originally passed `PlayerEntity.class`.
                10,	/* This is a default value, used in the constructors for FollowTargetGoal that use
                                       fewer arguments. We need to include it to use this larger constructor that allow
                                       us to add a predicate. */
                checkVisibility,	// Whether this goal should check visibility. Originally passed `true`.
                false, // Again, a default value from the larger constructor.
                e -> !FBPowers.ILLAGER.isActive(e) /* This is the predicate that allows us to determine if the
                                                      vindicator should follow the entity in question. */
        );
    }
}