Flying through climbable blocks in creative mode slows you down

I have a feeling that this might be related to how one can climb vines.

Are these jungle vines or swamp vines?

Duplicate of MC-5410, please use the search function to see if your bug has already been submitted. Currently over 55% of tickets are being closed as duplicate.

I'm not sure why this was reopened. This is clearly the same issue as MC-5410.

MC-5410 is about flying down on a ladder, which stops you. This issue is about flying up or sideways, which simply makes you go slower.

Confirmed for 15w46a

Duplicate of MC-5410.

No, it's not. See the comments above.

Ah, it's up. Sorry. Didn't ever see this, will test in a few minutes.

Confirmed for 1.13.1.

Affects 19w14b

Affects 19w45a

Relates to MC-90212

I wouldn't say so. Those two behaviours are pretty much opposites. This one makes you do laddery stuff where you would not expect it and the other one makes you ignore the ladder where you would expect to be able to use it.

Okay, depends on how you look at it. Both of these bugs relates to unexpected behavior regarding flying of some sort and ladders/vines. My idea is just so Mojang easier can find somewhat similar bugs to fix.

Affects 1.15-pre1 and 1.14.4

Confirmed for 20w22b. Twisting vines slow you down in creative mode.

Confirmed in 1.16 Pre-release 2.

Confirmed in 1.16-pre4.

Confirmed in 1.16-pre5.

Confirmed in 1.16-pre6. I'd like to request ownership - I'll keep this ticket updated.

Completed.

Affects 20w27a

Can confirm in 20w51a.

Can confirm in 21w03a.

Can confirm in 21w05b.

Can confirm in 21w06a.

Can confirm in 21w07a. Video attached.

Can confirm in 1.16.5 and 21w08b.

Can confirm in 21w11a. Includes glow berry vines

Not just flying through them slows you down. Climable blocks slow you down in general when moving, not just when flying, which is annoying.

Can confirm in 21w15a.

Can confirm in 21w17a.

Can confirm in 1.17.

Can confirm in 1.17.1.

Can confirm in 21w43a.

Can confirm in 1.18 Pre-release 1.

Can confirm in 1.18 and 1.18.1 Pre-release 1.

Can confirm in 1.18.1.

I can also confirm this behavior in 1.18.1. Here's a code analysis of this issue along with a fix.

Code Analysis:

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

net.minecraft.world.entity.LivingEntity.java

public abstract class LivingEntity extends Entity {
   ...
   public boolean onClimbable() {
      if (this.isSpectator()) {
         return false;
      } else {
         BlockPos blockpos = this.blockPosition();
         BlockState blockstate = this.getFeetBlockState();
         if (blockstate.is(BlockTags.CLIMBABLE)) {
            this.lastClimbablePos = Optional.of(blockpos);
            return true;
         } else if (blockstate.getBlock() instanceof TrapDoorBlock && this.trapdoorUsableAsLadder(blockpos, blockstate)) {
            this.lastClimbablePos = Optional.of(blockpos);
            return true;
         } else {
            return false;
         }
      }
   }
   ...

If we look at the above class, we can see that there is only one check that is carried out before allowing a living entity to climb a climbable block. This check is to see if the living entity is in spectator mode, and if they are, they won't be able to climb climbable blocks, and if they're not, they will be able to climb climbable blocks. The game doesn't check if the living entity is currently flying before allowing them to climb climbable blocks, therefore resulting in this problem occurring.

Fix:

Simply adding an "if else" statement to the "if" statement to check if the living entity is a player and if they're flying before allowing them to climb climbable blocks will resolve this problem.

Current "if" statement:

if (this.isSpectator()) {
   return false;
} else {
...

Fixed "if" statement:

if (this.isSpectator()) {
   return false;
} else if (this instanceof Player player && player.getAbilities().flying) {
   return false;
} else {
...

Can confirm in 1.18.2.

Code analysis based on 1.18.2 with yarn mappings.

The easiest way to fix this would be to make net.minecraft.entity.LivingEntity#isClimbing() (or this.onClimbable() in @unknown's analysis) return false if the player is flying. In fact, this method already checks if the entity is in spectator mode. We just need to add a check if the entity is a player and they are flying.

To do this, override that method in net.minecraft.entity.player.PlayerEntity as follows:

@Override
public boolean isClimbing() {
    if (this.abilities.flying) {
        return false;
    }
    return super.isClimbing();
}

Can confirm in 1.19.

Can confirm in 1.19.2.

Following on from mine and @unknown's code analyses, I've double-checked our 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. 🙂

Also, if it isn't too much to ask, would it be okay if I could take ownership of this ticket since the current reporter has been inactive since June 2020 (over 2 years)?

This is not fixed in 24w44a. Please reopen. I still able to reproduce this.

In my testing, the issue appears to be fixed correctly. Could you please clarify exactly what is not fixed?

The issue be not fixed. Scaffolding slows me down for no reason. Actually is slow down any #climbable. Ladder, vine, scaffolding. Even air if I datapack add air climbing.