[MC-148671] Villagers can trample farmland

The Bug:

Villagers can trample farmland.

This issue can commonly be seen when farmer villagers wander and jump around their workstations.

Steps to Reproduce:

Build the setup as shown in the attachment below.

[media]

Summon a villager and wait for it to claim the composter as its workstation.
Give the villager some carrots so it can begin working.
Observe the behavior of the villager for around a minute and watch closely as it wanders and jumps around its workstation.
Take note as to whether or not villagers can trample farmland.

Observed Behavior:

Villagers can trample farmland.

Expected Behavior:

Villagers would not be able to trample farmland.

Code Analysis:

Code analysis by @unknown can be found below.

The following is based on a decompiled version of Minecraft 1.19.2 using MCP-Reborn.

net.minecraft.world.level.block.FarmBlock.java

public class FarmBlock extends Block {
   ...
   public void fallOn(Level level, BlockState blockState, BlockPos blockPos, Entity entity, float f) {
      if (!level.isClientSide
              && level.random.nextFloat() < f - 0.5F
              && entity instanceof LivingEntity
              && (entity instanceof Player || level.getGameRules().getBoolean(GameRules.RULE_MOBGRIEFING))
              && entity.getBbWidth() * entity.getBbWidth() * entity.getBbHeight() > 0.512F) {
         turnToDirt(blockState, level, blockPos);
      }
      super.fallOn(level, blockState, blockPos, entity, f);
   }
   ...

If we look at the above class, we can see that there are only two necessary checks that are carried out before allowing villagers to trample farmland. One of these checks is to quite simply see if the entity falling on the farmland is a living entity and if it is, the other check is then to see if "mobGriefing" gamerule is set to "true". If these two requirements are met along with the other criteria within the "if" statement, the farmland can be trampled. The game doesn't check to see if the living entity is a villager before allowing them to trample farmland, therefore resulting in this problem occurring.

Fix:

Simply altering the existing "if" statement within this piece of code to check if the living entity is a villager before allowing them to trample farmland will resolve this problem.

Current "if" statement:

if (!level.isClientSide 
        && level.random.nextFloat() < f - 0.5F 
        && entity instanceof LivingEntity 
        && (entity instanceof Player || level.getGameRules().getBoolean(GameRules.RULE_MOBGRIEFING)) 
        && entity.getBbWidth() * entity.getBbWidth() * entity.getBbHeight() > 0.512F)

Fixed "if" statement:

if (!level.isClientSide 
        && level.random.nextFloat() < f - 0.5F 
        && (entity instanceof LivingEntity && !(entity instanceof Villager)) 
        && (entity instanceof Player || level.getGameRules().getBoolean(GameRules.RULE_MOBGRIEFING)) 
        && entity.getBbWidth() * entity.getBbWidth() * entity.getBbHeight() > 0.512F)

Linked issues

is duplicated by 12

MC-148611 Farmers Trample Farmland Resolved

MC-149205 Vilagers go on top of compost Resolved

MC-149606 Villagers destroying their own farm on accident Resolved

MC-151314 Villagers (Farmers) jump down from the composter, so that crash the harvest and farmland Resolved

MC-151324 Villagers often jump over composters, causing trampling farmlands. Resolved

7 more links

relates to 1

MC-148715 Farmers can plant seeds on a non-farmland dirt block Open

Attachments

Villager Jumping Next To Water Irrigation.mp4

Comments 21

James Cressey 2019-07-07T13:10:43Z

They also jump next to waterlogged blocks that are there for hydrating the farmland, which also tramples farmland:

[media]

Rachel Smith 2019-08-06T23:16:34Z

As a possible fix, why not add a "Soft Step" attribute to villagers that makes them unable to trample farmland no matter how they fall on it?

If it's a tag added to the Entity data shared by mobs, makers of adventure maps could also make the mobs of their choice unable to trample farmland.

Gravinser 2019-11-03T07:04:32Z

can reproduce in 19w44a

T3sT3ro 2020-03-20T16:39:03Z

still happens in 1.15.2.

Daisy Jett 2020-03-20T17:49:10Z

confirmed in every single nether update snapshot.

11 more comments

Gravinser 2020-04-02T19:11:10Z

can reproduce in 20w14a

Pelle Reinke 2020-04-20T20:07:23Z

Still present in 20w16a.

Would it not be possible to make an excemption for farmer villagers that they cant trample farmland?
Or perhaps give them the abillity to hoe farmland they have trampled.

Dylan Way 2020-05-06T18:01:26Z

20w19a now, how has this not been resolved?

numeritos 2020-06-21T00:06:14Z

Affects 1.16-rc1

Johan Vestergaard Paulsen 2020-08-15T15:34:44Z

Workaround is possible: Place a solid block somewhere over the composter, preventing the farmer from climbing on top of it. This fixes the occurrence, but of course only works as a workaround.

Marty McFly 2021-06-16T16:53:58Z

Affects 1.17

ampolive 2021-07-29T22:40:55Z

Can confirm in 1.17.1.

muzikbike 2021-09-01T19:57:31Z

Could also be fixed by modifying village structures to have solid blocks two blocks above composters to prevent jumping on top of them.

T3sT3ro 2021-09-01T21:01:40Z

Valid hack but not a solution to the problem.

Avoma 2022-01-15T19:46:27Z

Can confirm in 1.18.1.

[media]

Avoma 2022-02-21T10:06:31Z

Can confirm in 1.18.2 Pre-release 1. Here's a code analysis along with a potential fix regarding this issue.

Code Analysis:

The following is based on a decompiled version of Minecraft 1.18.1 using MCP-Reborn.

net.minecraft.world.level.block.FarmBlock.java

public class FarmBlock extends Block {
   ...
   public void fallOn(Level $l, BlockState $bs, BlockPos $bp, Entity $e, float $f) {
      if (!$l.isClientSide && $l.random.nextFloat() < $f - 0.5F && $e instanceof LivingEntity && ($e instanceof Player || $l.getGameRules().getBoolean(GameRules.RULE_MOBGRIEFING)) && $e.getBbWidth() * $e.getBbWidth() * $e.getBbHeight() > 0.512F) {
         turnToDirt($bs, $l, $bp);
      }

      super.fallOn($l, $bs, $bp, $e, $f);
   }
   ...

If we look at the above class, we can see that no checks are carried out to see if the living entity is a villager before allowing them to trample farmland. The only relevant check that is in place is to see if the entity trampling the farmland is a living entity, and if it is, the farmland can be trampled. This is evident through the following line of code:

$e instanceof LivingEntity

Since the presence of a living entity and not the type of entity is the only relevant requirement for a farmland block to be trampled, we can therefore safely assume that villagers can trample farmland.

Potential Fix:

Simply altering the existing "if" statement within this piece of code to check if the living entity is a villager before allowing them to trample farmland, should resolve this problem. The following line of code could be used in order to fix this:

if ($e instanceof LivingEntity && !((LivingEntity)$e instanceof Villager))

The fixed and correct piece of code within its class should look something like the following:

net.minecraft.world.level.block.FarmBlock.java

public class FarmBlock extends Block {
   ...
   public void fallOn(Level $l, BlockState $bs, BlockPos $bp, Entity $e, float $f) {
      if (!$l.isClientSide && $l.random.nextFloat() < $f - 0.5F && ($e instanceof LivingEntity && !((LivingEntity)$e instanceof Villager)) && ($e instanceof Player || $l.getGameRules().getBoolean(GameRules.RULE_MOBGRIEFING)) && $e.getBbWidth() * $e.getBbWidth() * $e.getBbHeight() > 0.512F) {
         turnToDirt($bs, $l, $bp);
      }

      super.fallOn($l, $bs, $bp, $e, $f);
   }
   ...

VorCas 2022-06-07T15:46:10Z

At first, I felt this was an issue. However, I no longer feel this way: Even in "real", situations can occur which can and do trample crops. This ranges from combat to trespassers taking a "shortcut" through a farm field.

Instead, what I believe the issue is:

Villagers themselves should attempt to avoid actions that would trample crops in normal circumstances. A villager being chased by a zombie, for example, is not going to stop and consider if his running away will trample crops; He is going to run for his life! This is the same reason am iron golem will not wait for a zombie to move to a clear spot before trying to engage the zombie in combat.

There are two immediate "fixes" I can imagine:

(1): Re-arrange generated farms to place the composter either on a block not direcly adjacent to farmland, or lower the composter by one block so villagers will not "jump down" to get off the composter.

And/or (2): Check at an appropriate place in the villager movement code if the next move might trample crops, and choose an alternate route/movement if it might. This way, the check can be skipped if the villager is "fleeing in terror and does not care about crops". It would also affect them if, for example, a tree had spawned in such a way that the leaves become another possible place to "leap down" upon crops.

Passzzz 2022-10-10T12:45:59Z

How to fix it. Just prevent villagers to jump on their job blocks.

Avoma 2022-10-13T13:35:15Z

Following on from my code analysis, I've double-checked my proposed fix and I can confidently confirm that it's fully functioning and works as expected, so I've attached two screenshots to this report, one of which shows the current code and the other that shows the fixed code. I feel this information may be quite insightful hence my reasoning for providing it. 🙂

[media][media]

Brain81505 2023-01-19T03:02:20Z

Can confirm in 23w03a

4ebugger 2024-04-15T14:14:50Z

I'll think about how to fix it, perhaps make villagers will not jump on their job site block to parity with Bedrock Edition? this is a way to solve.