Spawners randomly stop working

[anonisnap]

Description (Required)

I noticed after having played on a server for around a month, that randomly Electric Spawners would stop spawning for extended periods of time, upwards of minutes at a time, with plenty of power supplying them. Recently this has become a permanent issue, with some spawners refusing to spawn mobs in certain locations.

When a spawner, which refuses to spawn mobs in a location is moved to a new chunk far away, it starts spawning again with no issues. But moving it back to it's former location, it continues to not spawn anything.

In this image, 2 Electric Spawners are visible, a Skeleton on the left, and Cave spider on the right. You can see that a Cave Spider is spawned, and that spawner works without any issues. But the Skeleton spawner on the left has not been spawning for weeks. Both of these are in the same chunk as well.

My thoughts

The only thing I could point to, which could help solve this mystery, would be, that for each Spawner / Block Location, the plugin might think a different block is placed, leaving it to not care about the spawner. Or, that the block gets forgotten by Slimefun 4 itself.

Steps to reproduce the Issue (Required)

I'm unsure of how to reproduce this. Being unsure of what's causing this, it's hard to reproduce

Expected behavior (Required)

Both spawners should spawn mobs

Environment (Required)

Minecraft and Slimefun Version
Addons

[Boomer-1]

this sounds a lot like a block storage issue, where the sf data is lost. if you mine up the spawner and it's a cs-corelib head that may confirm it. or if you are unable to access the gui of the spawner

[James-P-Bennett]

I've observed this happening and after some troubleshooting I have found out the following:

• Electric spawners that quit working can still be picked up.

• No matter what changes placing new electric spawners in that same block doesn't resolve the issue.

Equipping the Slimefun debug fish, spawning a test block then clearing block data, breaking the test block then replacing it with a spawner completely fixes the issue.

So based on this, it's safe to assume that somehow the block state of the spawner or the block that the spawner is in is getting messed up.

EDIT: It was a timings issue. Refer to my PR for the fix.