Factorio Forums

1. What did you do?

[Guessing the events/order here based on end state and knowledge of my circuitry]
0. Be in sandbox mode (hope this doesn't matter).
1. Smart stack INserter, presumably with (whitelist) pipe filter + stack size 2, picks up 2 pipes, to feed Set-Recipe Engine Unit assembler.
2. Assembler Set Recipe from Engine Unit -> Electric Engine Unit. Probably some ingredients moved to trash slots and inserter entered Target Full state.
3. Circuit-changed stack inserter's whitelist filter from Pipe -> Circuit, stack size 2(?) -> 4.
4. Outserter finishes emptying the machine's trash/output slots.

2. What happened?

Stack inserter remains in state Target Full, and does not drop the 2 pipes.

See the bottom-left-most HUB inserter in the "Mall" ship in attached save file, which is still in the stuck state.

3. What did you expect to happen instead?

Inserter drops the 2 pipes into the machine because 1. The machine is no longer full, and 2. The item in its hand does not match its current filter.
AFAIK even stack inserters drop filter-mismatched items immediately, regardless of whether they're ingredients of the machine they're facing.

4. Does it happen always, once, or sometimes?

EDIT: Always, see reprod save in reply.

Save file includes ongoing stuck state. Toggling the inserter's filter off and back on, even while in sandbox pause state, unsticks the inserter, which makes me suspect that I'm *not* missing some reason this is working as intended, and that the inserter is actually in a bad state.

So it has only happened once, but it's ongoing and I suspect it's reproducible with some trial and error. Can attempt to find a reproduce state if the stuck state isn't enough.

Mods: bring-back-space-casino and hazard-concrete-recycling, but these seem unrelated and I assume inserter state-checks shouldn't be breakable by a mod.

It reproduced after letting the same request loop keep churning, this save is paused 10-15 seconds before the same bottom-left inserter gets stuck in the same manner (drive link this time since save is large): https://drive.google.com/file/d/1iPfykq ... sp=sharing

Looks like my guessed steps were pretty much accurate. Machine might've been emptied in the same tick that the inserter set Target Full state?

Thanks for the report. Issue is now fixed for 2.1.13.

Issue was caused by the "Set recipe" having a dump inventory which is only allowed to extend up to 1 item stack through item insertions, and 2 different inserters trying to insert 2 different items at the same time when recipe was already cleared. First wrong item went into dump inventory and second inserter was unable to insert other wrong item and as such the inserter went to sleep, but the assembler never notified that inserter to wake up when dump inventory was emptied making space for other item to go through.

Thank you!