I tried adding this to my world because it sounded really helpful. But I had to disable it immediately as it had slowed my game to a crawl. Is this a temporary thing as it's indexing or could this be a bug?

Tested in Factorio v0.16.24

Opening the file control.lua and changing the line 2 to (ignore the square brackets):

[if from.valid_for_read and ((not to.valid_for_read) or (to.name == from.name and to.count < to.prototype.stack_size)) then]

Seems to have fixed the lag in my game.

I am new to lua modding, but my guess to the issue is that when [on_player_inventory_changed] gets called and you have a filtered slot in the quickbar that is partially filled, the function [transfer_stack(from,to)] tries to fill that slot by calling [to.transfer_stack(from)].

[to.transfer_stack(from)] would try to move every item in every nonempty slot in the inventory into the filtered slot, and registers [on_player_quickbar_inventory_changed] and [on_player_main_inventory_changed], both of which calls [on_player_inventory_changed].

But if you have no more of the item in the inventory to fill the filtered slot, [to.transfer_stack(from)] will just keep trying to move item A into the slot filtered with item B, and it would not be successful, and you would be stuck in a loop calling [on_player_inventory_changed] over and over.

I think my fix works by adding a check to stop calling [to.transfer_stack(from)] to try to move item A into a slot filtered with item B, so the game won't fall in the loop.

Also changing line 49 [transfer_stack(providing[i], inventory[j])] to:

if providing[i].valid_for_read then
transfer_stack(providing[i], inventory[j])
else
break
end

Seems to make it run slightly faster by exiting a loop early in some cases, but it might just be placebo effect on me.
Hope Thaui won't be angry at me pasting modified codes here =w= .

There is no problem in helping improving the code, unfortunately I can't update today, but wednesday I can do it.

The fact is that the mod trigger itself an inventory update which makes the mods processing it and triggering itself again in a loop, I need for that to make sure that for each transfer, some conditions are verified so only real transfer (not the null ones) are done

AMCH0507, thanks for the propositions but the first one really help a lot, but the secondary can't be used as proposed since it would make the mod not working properly and since the mod don't run again in a loop, it's like a placebo effect. I've updated the mod with an added debug setting if this problem is still here, you can see every operation the mod does.

Well thank you Thaui for making and updating the mod. I wished to have something like this before, but I am not good enough with lua to make it myself. Your code helped me understanding it a lot.

Well in fact I wish the devs put this in base game.

I think they should =w=