With the addition of the ability to cancel the ProjectileHitEvent you can now prevent chorus flower from breaking by cancelling the ProjectileHitEvent .

I have sort of achieved protecting this block, but this is far from being both convenient and satisfactory. It can cause visual glitches or even a ghost block, but this is the best I could do.

    /**
     * Prevents Chorus Flowers from being broken by an arrow or a trident
     * @param e event
     */
    @EventHandler(priority = EventPriority.LOW, ignoreCancelled = true)
    public void onProjectileHitBreakBlock(ProjectileHitEvent e) {
        // We want to make sure this is an actual projectile (arrow or trident)
        if (!(e.getEntity() instanceof AbstractArrow)) {
            return;
        }

        // We want to make sure it hit a CHORUS_FLOWER
        if (e.getHitBlock() == null || !e.getHitBlock().getType().equals(Material.CHORUS_FLOWER)) {
            return;
        }

        // Find out who fired the arrow
        if (e.getEntity().getShooter() instanceof Player &&
                !checkIsland(e, (Player) e.getEntity().getShooter(), e.getHitBlock().getLocation(), Flags.BREAK_BLOCKS)) {
            final BlockData data = e.getHitBlock().getBlockData();
            // We seemingly can't prevent the block from being destroyed
            // So we need to put it back with a slight delay (yup, this is hacky - it makes the block flicker sometimes)
            e.getHitBlock().setType(Material.AIR); // prevents the block from dropping a chorus flower
            getPlugin().getServer().getScheduler().runTask(getPlugin(), () -> e.getHitBlock().setBlockData(data, true));
            // Sorry, this might also cause some ghost blocks!
        }
    }

Hey, yeah no protection plugin is actually preventing that block from being broken.

I think that using EntityChangeBlockEvent would have a lot of sense and wouldnt break any stuff. For example, if you hit a TNT block with a burning arrow, this event will be called and you are able to cancel it and prevent the TNT from priming

Hello, I also have such a problem and I don't know how to solve it :/

I'm still not sure why people want to make the ProjectileHitEvent cancellable. Cancelling an event should actually stop the action named in the event. If it doesn't, or can't, that event shouldn't be cancellable or the event should be renamed. If I cancel a ProjectileHitEvent.. the projectile still hits the block. Yes you could code it to not process the hit if you cancel the event, but it goes against how the event is named and isn't very intuitive.

Another issue.. cancelling ProjectileHitEvent has the potential to cancel other events. For example, if an arrow hits an Entity and one plugin cancels that ProjectileHitEvent, then EntityDamageEntityEvent can't occur because the hit didn't happen. If other plugins are correctly monitoring EntityDamageEntityEvent for projectile hits, they won't even see that event occur because one plugin decided to cancel a completely different event. At least with the current system, if I cancel EntityDamageEntityEvent, other plugins still get it and can make their own decisions what to do. If the change is made, will I now have to somehow monitor ProjectileHitEvent to make sure some other plugin doesn't snipe my EntityDamageEntityEvent?

As I said before, there is already a perfectly named event, EntityChangeBlockEvent, that not only has the correct parameter set but SHOULD be triggered when this happens based on its name. 

Would it be difficult to add some checks in ProjectileHitEvent (if Entity == Arrow and Block.getType() == Material.CHORUS_PLANT) and then just create an EntityChangeBlockEvent if those are true? And yes I realize the actual code might look a little different. The event already has the correct parameter set, you'd just need to pass the arrow and chorus plant block to it.

Sure the first three.

Did you even read any of the comments before commenting...

Isn't this captured by ProjectileHitEvent? Add a possibility to set/get a EventResult or implement Cancleable?

Wooden buttons are also affected by arrows (they trigger when you shoot them)

When I was trying to implement this protection for chorus plants in my plugin I thought for sure it would trigger the EntityChangeBlockEvent. You have an Entity (arrow) changing a block (chorus plant). This would have been easy to implement too.. it's simple to get the player as the ProjectileSource from the arrow and the block directly from the event.

Making the ProjectileHitEvent cancellable makes a bit less sense. Cancelling the event doesn't stop the projectile from hitting the block.. the only way to really do that is to delete it or change it's velocity. It seems like that event was meant as just a notification. But cancelling the EntityChangeBlockEvent does make sense, because you are actually stopping the entity from changing the block. Just my $.02

Bells, Campfires and TNT are the other blocks affected by arrows.

Or using world.capturedBlockStates for the block changes and call EntityChangeBlockEvent for them.

Arguably the best way to do this is to make the projectile event cancellable.

What exactly cancelling that event would do in the general case is a bit iffy though - if cancelling was defined as to just not run the hit code then that would likely be ok imo.