I have not been able to crash 2.1.9 with FMTK 2.1.4, even doing some debug actions that crashed 2.1.7/2.1.8 right away. So 2.1.9 is a big improvement.

Thank you @justarandomgeek and everyone at Wube for your hard work.

I was editing a migration file that had a breakpoint in it and at some point I renamed the file (from foo.lua to bar.lua). So the foo.lua was gone (and your explanation make sense, if it tried to revalidate the breakpoint in foo.lua, it would fail).

Had the game sitting under the debugger on a breakpoint for a while, editing some of the source code files.

Then moving cursor out of vscode, game crashed immediately.

I resolved this and my takeaway is “don’t add a metatable to a global object”.

I moved everything inside my code to be locals and only expose as globals when I require my code in (by returning a function which can return multiple values) and then do

GlobalA, GlobalB = require(‘my-code’)()

Sure ...

If you don't want to dig into mods but use a smaller reproducer, use the two attached mods.

in inventory sensor data-updates, you do:

require('lib.init')
Framework.post_data_updates_stage()


`lib.init` resolves correctly but is already cached from your earlier call in data, so it does nothing, and you discard the returned reference. You then call into the global var Framework, which ...

This is a change between 2.0 and 2.1.

In a number of my mods, I use a mechanism where I dynamically load files based on the presence of other mods. The relevant code is here: https://github.com/hgschmie/factorio-core-libs/blob/main/framework/other-mods.lua

When I install two of my mods that use ...

It seems that LuaTrain lost get_contents(), get_fluid_contents() and get_schedule() (LuaSchedule being fully unsupported now?) but there was nothing in the release notes about this.

Is the “official way” to get train contents to just enumerate wagons or is there a different/better way? Given that ...

It is not a mod problem. There is nothing in the code that would create those messages; this comes out of the engine.


This looks exactly like the "cidl-drop-near" message from ChangeInserterDropLane .


Yes, you are correct. Sorry for the noise. Turns out that mod snuck into my testing/debug ...

It is not a mod problem. There is nothing in the code that would create those messages; this comes out of the engine.

Copy and pasting settings from an entity to another (the underlying entity is an inserter):
I found no reference what that means. Some left-over debug message?

So I have this hybrid entity, which is stacking a loader and an inserter on top of each other.

Generally it seems to work ok, except when it comes to wire connections. And at this point, I ran out of ideas.

This is what I see in the game:

Screenshot 2026-06-19 at 15.07.40.png

On the right ...

(Followup to my own post)

After having some discussions with @_CodeGreen, I believe that the current behavior of create_entity when fast replacing an entity is a bug. There are valid reasons to not use apply_upgrade() to upgrade an entity but use create_entity with fast replace and in that case ...

according to all documentation (and the interwebs), this used to work in Factorio 1.1:


-- add an anchor to the topmost frame
anchor = {
gui = defines.relative_gui_type.train_gui,
position = defines.relative_gui_position.top,
},


and then attach this to `player.gui.relative` and you can get a ...

I have an entity that is an ElectricEnergyInterface:


{
type = 'electric-energy-interface',
name = 'control-station,

energy_source = {
type = 'electric',
buffer_capacity = '400kJ',
input_flow_limit = '12250kW',
output_flow_limit = '0W',
usage_priority = 'secondary-input',
drain = '250kW ...

Thank you. To close the loop here as well, it is not a bug: https://github.com/hgschmie/factorio-LogisticTrainNetwork/issues/65

Screenshot 2026-05-24 at 21.39.31.png

In the example, you set the depot priority for the provider station. You need to use the provide priority setting on the right ...

Here is what I did

- developed a new mod "B". It depends on version "1.0.1" of an existing mod "A"
- have a local version of the "A that is "1.0.1" and a fallback to "1.0.0" (mod_a_1.0.0.zip while 1.0.1 lives in a directory)
- release "A" 1.0.1 to the mod portal
- remove the directory that contains ...

There are two ways of adding new records to a train schedule: a specific rail (LuaEntity), maybe refined with rail_direction or a train stop name. The former allows to exactly pinpoint where a train should go, the latter tells the train "find any station with that name and go there".

It should be ...

When trying to add a new schedule record to a LuaSchedule for a train, if the AddRecordData refers to a rail, the rail must be on the same surface as the train.

Now, this makes sense for the base game, but it makes scheduling routes that cross surfaces (e.g. LTN + Space Exploration) difficult ...

I would have expected the engine to catch this (and maybe crash the mod) after a certain number of levels (e.g. 100 or so). The "crash straight to MacOS" was surprising.