The bug
Exploding tnt minecarts drop a minecart and can drop a tnt item if they were ignited by fire. Normally the explosion then destroys the items, but there should not be a reason for the minecart to drop anything in the first place. Additionally MC-116669 can be used to prevent the explosion from destroying the items.
How to reproduce
Use the steps provided in MC-116669 and then enter the world again after the crash.
→ All exploded minecarts dropped an item
Code analysis
Based on 1.11.2 decompiled using MCP 9.35 rc1
The method net.minecraft.entity.item.EntityMinecartTNT.killMinecart(DamageSource) calls the parent method and drops the tnt item regardless of whether or not the minecart exploded.
Important: If this is changed so that the parent method is not called all the time this method should first mark the entity as dead, otherwise MC-116669 could cause two exploding tnt minecarts to explode each other infinitely and multiple times.
Related issues
is duplicated by
MC-8460
TNT Minecart in Lava False Explosion
MC-9244
Minecart with TNT drops minecart and TNT block.
MC-9792
If a TNT cart blows up another one, the blown up TNT cart drops a normal minecart.
MC-10771
minecarts still dropping in 13w09c in creative
MC-13267
Minecart with TNT
MC-15264
TNT doesn't go away after blowing up
MC-17131
TNT carts sometimes drop their loot when being blown up by lava
MC-27498
TNT Minecart explodes and drops additional TNT
MC-28190
TNT remained after blow up with tnt mine cart on fire
MC-37934
Minecart with TNT and fire
Attachments
Comments
migrated
migrated
Confirmed
migrated
Confirmed
migrated
I just tried it and it still happens in version 1.5.
migrated
Apparently this isn't limited to just creative mode and exists in 1.6.2... Just watched Etholabs Mindcrack episode 106 youtube video and he just discovered it for himself in survival. Roughly 5 mins into the video.
kumasasa
Confirmed for creative and survival.
migrated
Still happens in the latest snapshots, how has this been in the game for so long..
migrated
Duplication no longer exists in 1.8.
marcono1234
Confirmed for
1.10 using MCP
In vanilla Minecraft it is impossible to notice because the item is immediately killed by the explosion
net.minecraft.entity.item.EntityMinecartTNT.killMinecart(DamageSource) (MCP 9.30)
public void killMinecart(DamageSource source)
{
super.killMinecart(source);
double d0 = this.motionX * this.motionX + this.motionZ * this.motionZ;
if (!source.isExplosion() && this.worldObj.getGameRules().getBoolean("doEntityDrops"))
{
this.entityDropItem(new ItemStack(Blocks.TNT, 1), 0.0F);
}
if (source.isFireDamage() || source.isExplosion() || d0 >= 0.009999999776482582D)
{
this.explodeCart(d0);
}
}Thank you for adding the affected version, can a mod please reopen this report?
migrated
But if it doesn't happen in vanilla minecraft, why is it an issue?
marcono1234
It happens very likely in vanilla, but the item is killed by the explosion. I just don't see any reason why it should explode and drop an item even if the item cannot be picked up.
FaRo1
Can't confirm for 1.10.2.
marcono1234
Like I said you cannot confirm it in vanilla Minecraft because the item is killed by the explosion. Please add that to the description.
FaRo1
Well, you could set a repeating command block to make every item invulnerable. (I'll try that tomorrow.) If that doesn't work either, this bug is irrelevant. Or can the item be seen in another way in vanilla?
marcono1234
@unknown please see the discussion @unknown and I had. The command block will be very likely unable to find the item because the explosion destroys it instantaneously, but there is no reason why the item should spawn at all.
migrated
Please test if this issue can actually be seen in vanilla, if not the bug is irrelevant, and thus invalid.
FaRo1
I repeated the test multiple hundred times with the repeating block and got no drops at all. Unable to reproduce in 1.10.2 Vanilla.
marcono1234
I thought we had this discussion already...
I just don't see any reason why it should explode and drop an item even if the item cannot be picked up.
The command block will be very likely unable to find the item because the explosion destroys it instantaneously, but there is no reason why the item should spawn at all.
migrated
It has no effect on the vanilla game, as such this bug is irrelevant.
pokechu22
Relates to MC-59517.
migrated
Reopened, on request, not that it's vanilla affecting, but could still be fixed.
wobst.michael
Cannot reproduce in 16w41a. Can someone else confirm?
migrated
The item is instantly destroyed, this can only be checked by looking at the code.