Before 20w27a, you were able to jump out of 2 block high spaces while sneaking. But due to the fix of MC-2404 this has led to a case where this is no longer possible. The behavior now seems to be like if sneaking applies an "invisible barrier" on you that has some side-effects with knockback resistance or status effects (See MC-200282 & MC-199326), which in this case is jumping.
While it doesn't seem to be a very noticeable issue at first, it gets very problematic to walk through narrow places such as diagonal stairs or underground caves in situations where remaining sneaky was critical, such as PvP on servers or when trying to avoid sculk sensors in deep dark / ancient cities.
How to reproduce:
Create a void world.
Place a block under and above you (see attachment).
Try to get out while sneaking and jumping at the same time.
❌ You can't.
Attachments
Comments 11
I see, for some reason i thought that got fixed before 1.16 released. Also makes sense, thanks for letting me know.
Hmm, now that i think of this, is it really intended and not a side-effect of fixing MC-2404? After some hours of gameplay i noticed this behavior so many times when exploring caves and sometimes it gets really annoying, i'd rather like to have a proper dev response about this. Also, it's almost the same issue as MC-199326 which got marked as Community Consensus.
The way that sneaking now works since MC-2404 is fixed, is that sneaking still makes an invisible border to prevent falling off blocks if you are up to 0.6 blocks above the ground. Before, it did only if you were on the ground. A way to fix this issue could be by making sneaking only make the border, if you are standing on the ground or falling, but not when moving upward. This would allow you to get out of it and it would also allow mobs to knock you out of it.
This issue also affects up to 1.18 Pre-release 5. I was testing this since this stuckness prevails even when players are launched with high X/Z velocities but Y velocities too low to launch them over the 0.6-block threshold (which is an issue with server plugins/map-making when you want to launch a player off a platform which they can just avoid by sneaking).
I attached a video showing it.
Code analysis (tentative)
Could this be because at some point, player jump velocity was increased ever so slightly so now the player hits their head.
Causing traps like this https://youtu.be/Yal1h5wdncM?t=149
gnembon
This was intentionally fixed, see MC-2404.