Steps to Replicate:
1) Enter end of 1.8 world in 1,9 - with ender dragon not killed in 1.8.
2) Notice terrain is 1.8, no cages are present, but there is a portal in the middle.
3) /kill @e[type=EnderDragon], ender portal.
4) Remove DIM1 folder,
5) Re-enter end.
There will be the new 1.9 terrain, (obsidian pillars in circle), no bedrock portal or dragon.
Since the creeperface was removed, there is no way to spawn it either.
Comments 5
Not a bug:
Remove DIM1 folder,
Caused the problem.
As stated before, the state machine is set to "Dragon killed, portal spawned", See the relevant tags at http://minecraft.gamepedia.com/Level_format#level.dat_format
When messing around with the game files you'll have to face the consequences.
The majority of the advice on the internet for how to reset the ender dragon fight it "Remove the DIM1 folder".
This will not go away with 1.9 - as many many years of removing that folder has made the SEO favor it.
Therefore, I believe there should be some way via gamerule or otherwise to reset the fight, because I may have been the first, but I will not the be the last to have this happen.
For feature suggestions or changes please see: Minecraft Suggestions on Reddit.
I would be curious to know if/what an NBT editor says is in the level.dat of this world under DimensionData/1/DragonFight