The bug
When you place a slab directly into flowing water, it creates a new water source in the block, regardless of the hight of the flowing water. Also, the created water can fill a bucket but will be replenished before disappearing. In the attached image, the only source placed with a bucket is the one on the lime concrete. Applies to both top and bottom half slabs of all types.
How to reproduce
Place a water source that creates flowing water.
Place a slab in the water, it will turn into a waterlogged source block.
Linked issues
is duplicated by 10
MC-128692
Water Duplication (No Not The Classic Trick)
Resolved
MC-128721
Infinite water using 1 water bucket and 1 slab
Resolved
MC-128813
Slabs will become waterlogged if next to any water level
Resolved
MC-128823
when flowing water touches a slab. it turns it into a water source block and keeps on reapeting
Resolved
MC-128826
New water source created when water flows toward slabs
Resolved
Attachments
Comments 20
I have a grid on a creative world made entirely of slabs, and when I accidentally placed a water source and picked it back up, the entire island was flooded.
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I can confirm this bug on 18w16a.
I can see where Mojang was going with this, but the repercussions are sever for existing worlds. It is more realistic, and some may want that, but it breaks a lot of things
The new water physics, perhaps, should be settable at creation of the world, and disabled by default for worlds imported from old versions. There are serious implications for a lot of existing designs and worlds just from water being able to flow over slabs, let alone it effectively turning slabs into source blocks.
I think the mechanic needs more nuance if it's going to make it into a release. Either it needs to be configurable if implemented this way, or the mechanic needs to operate like traditional water blocks do and have a flowing water mechanism like there is with full blocks so infinite spread doesn't happen.
It could also be that we've seen the first pass at the mechanic and that Mojang already intended to evolve it over time. Time will tell!
Old worlds will not change until the water gets an update of some sorts.
Also, feature requests go to reddit. (r/minecraftsuggestions)
Also note, that water flowing into slabs that shouldn't create sources creating water sources is not intentional behavior (this exact ticket) and will either change to allow non-sources in slabs, or will change that there won't be sources created when no sources would be created without the slab.
For discussion regarding a bug report, please go to the Mojira reddit (r/mojira).
As explained by Moonbat, If you large floor or roof area covered of half slabs, A water source next to any slab will spread to every slab and become source blocks that can not be removed with sponges. It makes sense if the water spreads, but as flowing water, not as source blocks.
That is a different case. There is no flowing water. The behavior you’re describing is intentional; a block can become waterlogged if a water source can be created there.
I gotta say, I'm happy it doesn't apply to stairs, otherwise my entire mine would've be flooded.