Nether fortresses failing to generate

This was confirmed as intended in this video: https://www.youtube.com/watch?v=r1ABrlyrq30 (under Corrections around a minute into the video)

Edit: Note that these snapshot videos are not official sources, and shouldn't determine the resolution of tickets.

I guess it would appear so. The fortresses' starting points all appear to be in crimson forest biomes. I guess this one can be closed then. 

Not closing since it has already been triaged by Mojang.

I have pictorial/concrete evidence and world generation data to support this claim.

Incidentally, after wandering tens of thousands of blocks in the nether in version 1.15 (stressing: java edition) I found a very good spot to build a wither skeleton farm, but the desired fortress is not present if the same terrain is generated in snapshots 20w06a to 20w09a.

Evidence description:

seed:1894983001

Compare terrain and fortress generation in the 100 blocks radius around (x,z)=(3300,-4600)

Here follows pictures of the mentioned terrain in versions 1.15 and 20w09a:

I'd like to point as well that the picture in the current snapshot shows nether_wastes terrain.

Thus, I treat this as an unintended feature to be reported.

To you workers, a nice day.

The behaviour in your world is exactly as described by Slicedlime. The origin point for the fortress in your seed is at 3395 -4744, give or take 4 blocks. (The origin point for all nether fortresses is in that room with the lava "well")

In 1.15.2, as expected, that entire chunk occurs in minecraft:nether

In 20w06a, and 20w09a that chunk occurs in minecraft:warped_forest

Fortresses cannot generate if their starting points are in warped_forest or crimson_forest, as described by Slicedlime. You will sometimes see those fortresses in those biomes, it is because they began generation in nether_wastes or soulsand_valley and expanded into an adjacent biome.

So this is the behaviour expected of the world generator.

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Do I personally think this behaviour is detrimental and should be considered a bug? Personally, yes. It has the potential of being a severe restriction in how common nether fortresses are. The warped forests and crimson forests are fairly common biomes, and there is not much harm in having fortresses generate inside them. I also think the fortress bounding box should override the spawning restrictions of the biome in the same way that spawners work normally in a mooshroom biome, phantoms spawn in a mooshroom biome, and infested blocks will still generate in a stronghold in a mooshroom biome.

However, I recognize that at this point that this is on the fence between a bug report and a feature request.

Should be fixed in 20w16a

20w16a was just added as an affected version; was this actually tested? Fortresses were added to the generation of every biome this snapshot.

Following up. Nothing in the change log pointed to fortresses being able to start generating in every biome, but now there are other things to consider. 

I rendered the same seed in 20w16a. Fortresses as rare as in 20w15a.....but now there are bastions and ruins which also need space to generate (and can generate everywhere), and so the density/rarity of fortresses seems to make sense now. Attached a render for comparison to previous versions.

Is 20w16a affected? I don't know. It partly depends on how mojang wants the nether to look like, and it partly depends on someone in the community identifying an extreme edge case. I certainly didn't add 20w16 to the list.

I have confirmed this is an issue in 20w16a, but the issue is no longer related to biomes.

As we added new large structures to the nether in the Nether Update, we had to adjust the spacing and separation for fortresses accordingly to make everything fit without constant overlaps 🙂