The bug
When spam-clicking with the sword on the ground and run at the same time the character gets stuck.
This also happens when left clicking with the debug stick in Creative mode and when hitting blocks which can normally be broken instantaneously in Survival with a debug stick.
How to reproduce
Be in gamemode creative
Get a sword or a trident
Look at the ground and spamclick on the left mouse button
Try to run while you still spamclick with your sword/trident
Further notes by @unknown
This issue affects more than what is currently mentioned in here.
Any time the player (attemps to) break a block, but the block isn't broken server-side, the player gets teleported back to where they were when they broke that block.
This issue appears when running around while clicking the ground with a sword in creative mode I assume because the client is actually still sending 'block interaction packets' as they are technically still 'mining' the block. However, neither the client nor server break the block because the player is holding a sword.
This same issue can also be observed in survival mode when the server is lagging as the lag introduces 'block lag'. Block lag is when the player mines a block but the block re-appears due to not (yet) being broken server-side because of the lag. Before this issue was introduced the block re-appeared and that was that. Since this issue was introduced the player also gets teleported back as soon as the block re-appears. (Here's a video showing this on a vanilla singleplayer world where I caused excessive server lag for the purpose of demonstration.)
Also, while I know this isn't relevant for you guys, this issue also affects modded servers where the player isn't allowed to break certain blocks or blocks in certain areas. The block gets broken client-side, but then re-appears for the client in the next (server) tick, and since 1.14.4 (Pre-Release 4?) the player gets teleported back to the location they were at when they broke the block client-side. (Here's a video of that on a spigot 1.14.4 server with a plugin that offers such functionality.)
This is almost certainly caused by the fix for MC-156013, and MC-156852 might be in the same boat. What is the point of pre-releases anymore if changes introduced in them cause more issues than they solve and make it into the final releases for a version? Anyhow, my point is that fix implemented for MC-156013 is plain bad and I can't trust you guys to not fix this issue by doing something equally bad, like adding a check that doesn't teleport the player back if they're holding a sword.
With that said, a better fix for MC-156013 using the current method is probably to teleport the player back only if the player's hitbox intersects the re-appearing block. This would get rid of this issue as well.
Linked issues
is duplicated by 100
MC-156756
screen bug with the sword
Resolved
MC-157199
character slows down when punching grasss
Resolved
MC-157579
Hitting Blocks with a sword in Creative mode greatly affects player movement
Resolved
MC-157609
Bug while hitting a block fast with a sword
Resolved
MC-157678
Left clicking a sword
Resolved
relates to 3
Comments 46
Note to TorandoChaser: block lag in single player has been a thing since 2012 when "single player" was changed to 1-person multiplayer (so that it wasn't 2 different programs for single player and multiplayer with 2 different lists of bugs). Turn your view distance up higher than you computer can handle and the first two symptoms are block lag and creatures freezing for a second or more partway through their animations.
Panda4994
This issue affects more than what is currently mentioned in here.
Any time the player (attemps to) break a block, but the block isn't broken server-side, the player gets teleported back to where they were when they broke that block.
This issue appears when running around while clicking the ground with a sword in creative mode I assume because the client is actually still sending 'block interaction packets' as they are technically still 'mining' the block. However, neither the client nor server break the block because the player is holding a sword.
This same issue can also be observed in survival mode when the server is lagging as the lag introduces 'block lag'. Block lag is when the player mines a block but the block re-appears due to not (yet) being broken server-side because of the lag. Before this issue was introduced the block re-appeared and that was that. Since this issue was introduced the player also gets teleported back as soon as the block re-appears. (Here's a video showing this on a vanilla singleplayer world where I caused excessive server lag for the purpose of demonstration.)
Also, while I know this isn't relevant for you guys, this issue also affects modded servers where the player isn't allowed to break certain blocks or blocks in certain areas. The block gets broken client-side, but then re-appears for the client in the next (server) tick, and since 1.14.4 (Pre-Release 4?) the player gets teleported back to the location they were at when they broke the block client-side. (Here's a video of that on a spigot 1.14.4 server with a plugin that offers such functionality.)
This is almost certainly caused by the fix for MC-156013, and MC-156852 might be in the same boat. What is the point of pre-releases anymore if changes introduced in them cause more issues than they solve and make it into the final releases for a version? Anyhow, my point is that fix implemented for MC-156013 is plain bad and I can't trust you guys to not fix this issue by doing something equally bad, like adding a check that doesn't teleport the player back if they're holding a sword.
With that said, a better fix for MC-156013 using the current method is probably to teleport the player back only if the player's hitbox intersects the re-appearing block. This would get rid of this issue as well.