Factorio Forums

I was testing a planet mod i was developing and I ran into a weird issue. A plant I've coded to have negative pollution emissions when harvested does not have this property when harvested by an agricultural tower and not by hand. I do not know what is causing the issue so I am reporting it as a bug.
The pollution caused by this anomalous behavior is also not working quite right, as it is not being absorbed by tiles nor recorded in the pollution graph.
As previously mentioned, harvesting by hand showcases the expected results.

Another weird detail was that by changing a pollution value of another "plant" from the mod, which is grown in a different agricultural tower, to also be negative this weird behavior did not happen. If this is not a bug but an issue with my mod I apologize for the inconvenience.

Here is a showcase of the bug.
https://youtu.be/_D9BFEUCIb0

Welcome on the forums and thanks for the report. Issue is now fixed for 2.1.

This issue is caused by need of agri tower to be seen as the source of pollution for the enemy pathfinding purposes, but it was implemented in a way that does not handle negative emissions: plant would add pollution and then agri tower would "undo" pollution at the plant's chunk and then add pollution to the chunk with agri tower. Issue here is that if pollution is close to 0, it could happen that plant with negative harvest emissions would fail to consume any pollution (since there is not enough of it) but the agri tower when "reverting" the pollution added by the plant would cause the total amount of pollution to increase. For 2.1 i made this logic more robust by having the plant itself to add pollution on the chunk of agricultural tower it is harvested by, thus removing need for the pollution transfer between chunks.

Summary is that for this issue to happen, there has to be a plant with negative harvest emissions, pollution must be already close to 0, plant must be on a different chunk than agricultural tower and it must be harvested by the agricultural tower.