The Bug:
Cave carvers don't cut through snow blocks.
Cave carvers cut through a variety of surface blocks such as mud, mycelium, podzol, sand, red sand, etc... so it seems rather strange that they don't cut through snow blocks.
Here is an example:
Version: 1.19.3
Seed: -51010235163883720
Coordinates: /execute in minecraft:overworld run tp @s 1127.30 80.00 1669.96 -29.47 17.73
Steps to Reproduce:
Generate a world with the seed provided above and teleport to the given coordinates.
Look at how the cave interacts with nearby snow blocks.
Take note as to whether or not cave carvers cut through snow blocks.
Observed Behavior:
Cave carvers don't cut through snow blocks.
Expected Behavior:
Cave carvers would cut through snow blocks.
Related issues
is duplicated by
relates to
Attachments
Comments


And "lose on a technicality" you shall, unless you, or someone else, proves that it also occurs in vanilla, unmodded Minecraft.
Confirmed in 13w21a.
This has happened since 1.3.2 at least, I have a world from that version with a shroom island that is just like this.

Is this still a concern in the current Minecraft version? If so, please update the affected versions in order to best aid Mojang ensuring bugs are still valid in the latest releases/pre-releases.
Note: this is a automatic message, so apologies if I miss something.

Affects 1.6.2

Fix
Quite near the end of the method:
MapGenCaves.generateCaveNode()
// if (blockTypeId == Block.grass.blockID) {
if (blockTypeId == Block.grass.blockID || blockTypeId == Block.mycelium.blockID) {
var49 = true;
}
// if (blockTypeId == Block.stone.blockID || blockTypeId == Block.dirt.blockID || blockTypeId == Block.grass.blockID) {
if (blockTypeId == Block.stone.blockID || blockTypeId == Block.dirt.blockID || blockTypeId == Block.grass.blockID || blockTypeId == Block.mycelium.blockID) {
I think the fix needs no explanation.
I attached a screenshot
showing the cave in its full glory, courtesy of fixed cave generator. (There are more nearby holes all around that place, they are just out of the view.)
Still an issue as of this post.

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.
@Galaxy_2Alex
This effects all versions through 14w03b

Affects the same way snow surface in Ice Plains -biome, at least in 1.7.5. See -861, -12, seed -4542366974610774625. Quite likely the same fix applies.
Fixed in 14w20?

No, Ice plains see Markku's coordinates above, Mushroom biome: -2983, 66 , -2460, seed -4542366974610774625
This was fixed. See attachment.

Nope, not fixed in 14w21b. That particular example shows a cave that pokes the surface somewhat perpendicular to it, which has had no problems. See the seed/coords mentioned by me and you can still find the same issue is there (at least for ice plains -biome).
EDIT: Actually, maybe the mycelium case is indeed solved, my memory being as poor as it is and it has been so long time; perhaps the cave wouldn't have even poked through the mycelium surface if the issue wasn't fixed... In any case, the ice plains snow surface is still bugged.
Second to last picture on there, starting with Minecraft_14w21b.

Not fixed in 14w21b.
Cannot reproduce.

@@unknown: -861, 64, -12, Seed -4542366974610774625

Is this still a concern in the current Minecraft version 1.8.1 Prerelease 3 / Launcher version 1.5.3 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.
(As of 15w51b) Looks like cave generation does cut through mycelium, but not snow. Also doesn't cut through packed ice (see the 3 most recently-added attachments)
One other little thing to note is that ravine generation follows slightly different rules than other kinds of cave generation, see MC-94487. I think that ravines will require their own separate fix.
Is this still an issue on the latest snapshot 16w44a?

Still issue, still the given example location shows: -861, 64, -12, Seed -4542366974610774625 (ice/snow)
Is this still a problem in Minecraft 1.11?
Can confirm for 1.13-pre5. I also noticed that the same applies to red sand in the 1.13 snapshots because now the caves and ravines will no longer cut through red sand just like they don't cut through snow and mycelium.
Confirmed for 1.13.2 and 19w08b.
Although this should be easy to fix with red sand, fixing this for snow blocks may (or may not) cause a new bug that may not be fixed. Since snow blocks generate in igloos and snowy villages, making caves cut through snow can cause these structures to become obliterated by the caves. Somewhat similar problems have already happened to diorite, andesite, and granite in the new village structures, as they could get replaced by ores and other stone types.

Depends on the order of generation. If caves are carved before igloos/villages are put in, there won't be a problem (assuming the igloo/village generation coming later is smart enough to not "build" over air). If the caves/ravines are done after igloos/villages, I'd imagine it is a "natural" consequence that anything in cave's/ravine's path gets handled just as violently as the natural materials like solid rock and dirt, i.e. removed.
In 20w15a this affects Blackstone too
It’s kinda a big issue inside Mesa biomes. This may be a forgotten bug but it should affect 20w18a.
affects 20w22a
Seems to be present with the new cave generation in 21w06a
Affects 1.16.5 and 21w13a. but 1.16.5 isn't listed in affected versions.
Affects 21w16a.
I suggest fixing this by having a list of blocks that shouldn't be carved - possibly only bedrock. Caves generate pretty early, after surface builders and before all other generation features, so it shouldn't cause problems.
Still exists in 21w18a.

Affects 21w37a, seems like it only affects snow blocks now?
They also don't cut through powder snow.

After testing for a while, it seems that red sand is still not cut by cave carvers in some occasions.
Not cutting into powder snow is intentional according to devs' Twitter. Not sure about the rest.

There are some instances where whole cave entrances might get covered in snow due to this, especially in groves / snowy slopes.
Powder snow not getting cut by caves might be intended, so ideally carvers should try to convert regular snow into powder snow, although that still won't fix snow blocks floating in the air.

Disagree with resolution. This often results in floating snow blocks, which are downright unsightly.

Also disagree with resolution. This mountain cave looks like a giant parkour course inside, floating and isolated snow blocks EVERYWHERE. And all the cave entrances are either completely covered in snow or covered with just enough to make it a chore to get through them. Aren't cave entrances supposed to be... entrances? I'm pretty sure if cave entrances in the plains biome were blocked by a thin layer of grass, that would be considered a bug. Why is this not? It's also worth noting that grass blocks are able to spawn inside caves, but AREN'T found floating in midair inside them. Surely the same would apply to snow blocks. This hardly seems intentional, this looks like an oversight at best or laziness at worst.
Confirmed for 1.18.2 and 1.19-rc1.
Can also confirm this behavior in 1.19. Here's an example of where this can be seen in this version.
[media]Version: 1.19
Seed: 7329541731365554898
Coordinates: /execute in minecraft:overworld run tp @s -806.62 122.53 133.86 -24.66 0.22
Can confirm in 1.19.2.
Version: 1.19.2
Seed: -2055074493936140863
Coordinates: /execute in minecraft:overworld run tp @s 38775.30 94.00 -3078.96 -433.26 -17.75
Can confirm in 1.19.3