Using version 3.0.4 I have regularly seen odd chunk generation and sudden cliffs, floating hunks of rock, etc.

Example --

ExtrabiomesXL does not determine biome placement or biome borders. ExtrabiomesXL does not generate base terrain for a chunk. This appears to be a bug in vanilla terrain generation that is related to lag. This bug can be reproduced in vanilla Minecraft by purposefully creating laf during terrain generation.

OK, thanks for the info.

I have the same problem.

I did experiments and discovered that the same seed generates the same biome boundaries, but not the same biomes. The same type of biome (in those borders) are maintained only until the server is stopped.

Example: If the server stops and starts again, the undiscovered chunk is newly placed mountains instead of the sea (with a sharp edge with the sea, the sea generated before stopping).

Reproducible.

Vanilla does not have this error, preserves biome type, even if the server is stopped.

I think this is seen in the screenshot. The sea and the meadow on the left, red mountains and wasteland right. Biome boundaries "sea-meadow" continues "mountain-wasteland."

Thanks for the info, weltar.

My research has not borne this out. But even so ExtrabiomesXL does not change anything about how Minecraft chooses biomes, except to give it more choices.

This still chalks up as a Minecraft bug.

For the record, I can recreate the problem by creating lag.

Weltar, your information has given me an idea. I think I know what is causing this. More later.

I REALLY appreciate your report!

@weltar Since you have a reproducible process, would you mind testing my hunch. I have made a special build of the mod (download). This version logs the biome array to the log...If you would recreate the problem and then see if the order of the biomes has changed in the list. the lists are found in .minecraft/ForgeModLoader-client-0.log and .minecraft/ForgeModLoader-client-1.log

Thanks!

Quick test, to miss more now. Still biome type changes after stop-stard and ... order of the listed biomes allways same :-o

server:
http://pastebin.com/a5BXni6X
http://pastebin.com/NDnYatnv

same, home server test, with forge 204, windows XP

I have a bug somewhere in my behavior, my settings. I will do more tests later.

I did some more testing and I can confirm that this odd chunk generation seems to happen only after a restart. Glad that it's being looked at rather than dismissed.

Some tests. Using ExtrabiomesXL:

• Turn off all additional biomes (xxx.enablegeneration = false), allowed vanilla (vanilla.xxx.enablegeneration = true) ... OK
• Allowed one or more additional biomes ... PROBLEM
• Disabled vanilla biome, one or more (using vanilla.xxx.enablegeneration = false), additional biomes still false ... PROBLEM

Uhm .. FML addNewBiome / removeBiome and related error?

THANK YOU immensely! I have made a jar edit to replace the mechanism FML uses to add and remove biomes. Please download and put in the jar file and test to see if the error persists.

I hope this takes care of the problem.

@weltar Your persistence and professional, concise problem reporting turned me onto the problem and fix. It is apparent that my testing was flawed and would never have led to any solution. I am going to report this to the FML team.

Thank you again.

WOW thank you for the VERY QUICK fix. It seems that now works.

For a given seed generates the same types of biomes, even after switching off and on the server. And even after repair client (for 1.3 predictably), singleplayer has the same layout.

Thanks a lot.

Test environment: win & linux server (with fix} + win client (without and with fix); win "single" (with fix). Forge 274 + va.class. MC (client and server) + extrabiomes-chunk-test.zip, client also with minimap, config deleted before the tests.

I have submitted a bug report and a proposed solution to the cpw/FML project.

THANK YOU immensely! I have made a jar edit to replace the mechanism FML uses to add and remove biomes. Please download and put in the jar file and test to see if the error persists.

Am I correct in thinking that I add this to my server.jar AFTER forge and before anything that uses forge?

yup

I can confirm that replacing the IdentityHashSets with ArrayLists fixes the problem at my end. Thanks for the speedy resolution Scott and weltar.

@keybounce

Correction by the FML team can generate a different biome order than the local repair.

So if you want to put it into full operation server, 'd be better to wait until the FML fix. Or you may eventually appear (just one) cliff line (like with MC version upgrade).

true

grumble grumble waiting then grumble grumble

Ok, now that the official fix is out in FML, is your fix compatible? Do you have a compatible fix?

... mystcraft can't work past 251 ... age generation ...

The fix above is compatible.