Light leaking through corners with Smooth Lighting on

Explanation on set 3:
(a) shows the glitch with the test setup. The two light patches point toward a hidden light source.
(b) shows the blocks behind the glitchy spot. Note the empty space above the glowstone.
(c) shows no glitch when the previously empty spot is filled with a solid block.

If the block removed between a and b is placed again after c, the result is no glitch on any of the blocks. So there seems to be some relation with the transparency of the blocks surrounding the light source in regards to whether the glitch appears or not.

when it's a corner like that, light will always pour in... just saying

@Devon: Um, since when? And which picture are you referring to?

Confirmed.
http://i.imgur.com/SY83XWe.png
http://i.imgur.com/0rEZhz8.png

Still present in 13w16a. Issue updated to reflect this.

I am pretty sure this has happened since at least the update Maximum smooth lighting was added in.

Is this still a concern in the current Minecraft version 1.7.4 / Launcher version 1.3.8 or later? If so, please update the affected versions in order to best aid Mojang ensuring bugs are still valid in the latest releases/pre-releases.

@Ezekiel

This is still an issue with those versions, and in 14w02c it is even more of an issue. (I have not tested the other two snapshots)

Confirmed for 1.7.5 and 14w11b

I'm having a similar problem, but in a slightly different situation. If I'm inside a building with stone walls and a roof made of slabs, and no light sources inside, there is a little bit of light at the top of each wall. The slab roof covers the walls, so there is no "crack" for light to seep in through.
This only happens when the roof is made of slabs and only with Smooth Lighting turned on.
It still happens if I extend the walls upwards.
But it doesn't happen if I replace slabs near the edges with stone blocks.
Cross sectional view:
1234567 (roof)
#_____# (walls and empty space)
If blocks 2 and 6 are slabs, light leaks in. If they are stone blocks, light does not leak. The other numbered blocks don't matter; they can be either slabs or full blocks. Blocks 1 and 7 can even be air without changing the result.

Is this still a concern in the current Minecraft version 14w30c or later? If so, please update the affected versions in order to best aid Mojang ensuring bugs are still valid in the latest releases/pre-releases.

Still an issue in 14w30c. Could reproduce it.

Confirmed for

• 1.8.7 Has also a strange effect on piston heads (see screenshot)

Example command

/summon MinecartCommandBlock ~ ~1 ~ {Command:/setblock ~ ~-4 ~ redstone_block,Riding:{id:MinecartCommandBlock,Command:"/execute @p ~ ~ ~ /setblock ~-1 ~3 ~1 air",Riding:{id:MinecartCommandBlock,Command:"/execute @p ~ ~ ~ /setblock ~-1 ~2 ~1 stone
",Riding:{id:MinecartCommandBlock,Command:"/execute @p ~ ~ ~ /setblock ~1 ~1 ~1 redstone_block
",Riding:{id:MinecartCommandBlock,Command:"/execute @p ~ ~ ~ /setblock ~1 ~2 ~1 piston 4
",Riding:{id:MinecartCommandBlock,Command:"/tp @p ~ ~ ~ 0 0
",Riding:{id:MinecartCommandBlock,Command:"/execute @p ~ ~ ~ /fill ~-2 ~-1 ~-2 ~2 ~3 ~2 stone 0 hollow
",Riding:{id:MinecartCommandBlock,Command:"/tp @p ~ ~15 ~
",Riding:{id:MinecartCommandBlock,Riding:{id:FallingSand,Time:1,Block:activator_rail,Riding:{id:FallingSand,Time:1,Block:redstone_block,Riding:{id:FallingSand,Time:1,Block:stone,Riding:{id:FallingSand,Time:1,Block:command_block,TileEntityData:{Command:/fill ~ ~-2 ~ ~ ~3 ~ air},Riding:{id:FallingSand,Time:1,Block:stone,Riding:{id:FallingSand,Time:1,Block:command_block,TileEntityData:{Command:/kill @e[type=MinecartCommandBlock,dy=6]}}}}}}}}}}}}}}}}

Is this still an issue in the latest snapshot 16w44a?

Confirmed for 1.12-pre7

May or may not be a different problem, but I've noticed light completely passing through corners of opaque blocks. The area I'm in in NotDark.png and NotDark2.png has no light sources, and the grass/dirt is right next to open daylight, so the daylight is bleeding in. On 1.13-pre1, macOS.

@unknown, this is MC-129725

Confirmed for 1.13.1.

Affects 19w14b

I can still se leaking light in corners in 20w17a *if *Smooth Lighting is turned on.

Confirmed for 1.16 Pre-release 2. As @unknown said, the issue only takes place if "Smooth Lighting" is either set to "Minimum" or "Maximum". 

Confirmed in 1.16-pre4.

Confirmed in 1.16-pre7.

Affects 20w28a, can I request ownership? Original reporter is inactive

@@unknown, completed.

Can confirm it's still a thing in 1.16.3

Can confirm in 20w51a.

Can confirm in 21w05b.

Can confirm in 21w06a.

Can confirm in 21w07a.

Can confirm in 21w11a.

Can confirm in 21w15a.

Can confirm in 21w17a.

I can no longer reproduce this in 1.17-pre2.

Likewise I cannot reproduce

This can be reproduced with stairs.

This can indeed be reproduced with stairs. I've attached a screenshot. Can confirm in 1.17 Pre-release 2.

This might have to do with some of these blocks having light literally inside of them, as opposed to full blocks which cancel light.

Edit: ... and that these blocks don't create shadows → MC-139621.

Should the stairs case be reported separately?

Can confirm in 1.17.

Can confirm in 1.17.1.

Can confirm in 21w37a.

Can confirm in 1.18.2 and 22w19a.

Can confirm in 1.19.

Can confirm in 1.19.2.

Can confirm in 1.19.2.

@unknown: The issue is already marked as affected in 1.19.2. Thank you for the additional confirmation though! 🙂