I am playing on Aternos using vanilla minecraft 1.12.2, and it seems there is a bug where no farmer villagers generate (the kind that give you emeralds for crops).
In one world, I spent hours exploring, visited more than a dozen villages and checked at least 150 villagers and not a single one of them was a farmer village, but there seemed to be an even distribution of the rest of the professions. Given that a single villager has a 1/24 chance of being a farmer, there is a >99% chance I would have found one farmer having checked that many villagers if villager generation was functioning properly. I also went into creative mode and spammed the villager spawn egg at least 50 times and did not get a farmer.
To make sure it was not just an issue with that specific world, I played on another world and found another 50 villagers and not a single one of them was a farmer.
At this point I feel like it's safe to assume that farmer spawning is broken on Aternos generate worlds for vanilla minecraft 12.2, unless I am missing something. Does anyone have any idea what is going on, or has anyone encountered this issue before?