Unable to jump when up against a block

It's not just walking forward, it is also backwards and sideways. Even diagonal.

Also mobs can't jump when touching the block.

And when going down on stairs you sometimes are hovering above the block. It seems that the block-hitbox is off somewhere....

And this makes it very unplayable. I hope this will get fixed and not left like the enormous lag-problem that the snapshots currently have (that makes it also almost unplayable). 

Probably came about from the "improved" collision code that was mentioned in the snapshot article.

Some improvements & functionalities were mentioned in the article; But don't people check to see if the update actually causes something else... Like Another obvious Bug??? Mojang?? Really?

EDIT: It is a snapshot... OK... the Team cannot correct every bug, but I am certain that they must correct some of these before releasing... or it won't make sense adding anything to the game at all.

Even on auto-jump, two slopes in a row will result in your character moving into the block. You can't autojump unless you are relatively far from the block.

I think this is a consequence of the changed collision mechanics as mentioned in the update.

And adding to the variety of machines experiencing this: Debian Testing on OpenJDK 11.0.2+7deb1 64-bit.

I am also having this issue. If I am holding the key to walk forward but am stopped by being up against a block, and I then hit jump, I cannot jump. Not until I either move away from the block, or stop walking forward. I agree with Third Eye, Igor, and others' comments above; this is an example of a very, very basic and vital gameplay mechanic that is unusable, which seems to be a repeated issue.

I understand that the whole purpose of the snapshots is to basically outsource bug-finding and general playtesting to the community, but I agree in feeling that the frequency of such basic issues like this is most likely a huge headache for everyone involved that could be solved in other ways; it seems to me that it would be more productive to have the snapshots playtested just slightly more thoroughly for the most basic usability, before releasing them to the public for more detailed and extensive playtesting. I feel like it's going to keep a lot of people from being able to play normally and thus find rarer but still important bugs, if they can barely use the basic gameplay functions, which just slows everyone's ability to help and sort of shoots the best utilization of the community in the foot. If we're all impaired in something as simple as moving around within five minutes, we stop being as effective at finding the things it actually takes time and involved gameplay to come across, which is where the community manpower seems like it would be best used. Not, dozens of people saying "hard to move" as soon as the snapshot is released. 

As far as actually solving this, I'm sure there are LOADS of people available worldwide who would be happy to be employed for a reasonable wage simply playing Minecraft to find these most basic bugs as fast as possible before every other snapshot user has to also deal with them. And for every bug a public release doesn't have, that's like, a minimum of half a dozen duplicate bug reports that no longer clog up the system for the people who have to handle and respond to them! 

@Remy Z That's why it's called "snapshot". It's "for those who are curious and can't wait, that's how far we are right now" and not "this is what you should play". If you expect basic QA to be done before you play, just wait for the (pre-)releases and play 1.13 until then. Mojang are just giving you the choice not to wait for their QA, what you are demanding would mean everyone would have to wait for the prereleases. It's not like Microsoft/windows forcing you to try their betas.

@_xlf Yikes. I'm not "demanding" anything, I'm echoing several other people's comments that this isn't the best way to utilize us as snapshot players for our ability to help. Our free help, even, which I'm pointing out is being somewhat wasted in situations like this. I'm trying to emphasize what would make us more useful to the devs, I'm not just sitting here complaining with no purpose. I'm identifying and elaborating upon a specific problem other people have also noted, pointing out why it's a problem, why it would be worth it to solve, and possibly how. 

hello , after the patch today is realy nice all jump work , its a plaisure to play again , thanks