The mod LTN Combinator Modernized (2.2.2) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event LTN_Combinator_Modernized::on_pre_build (ID 9)
Record is not a BlueprintRecord.
stack traceback:
[C]: in function 'get_blueprint_entities'
LTN_Combinator_Modernized/script/ltn_combinator.lua:2022: in function 'handler'
core/lualib/event_handler.lua:47: in function <core/lualib/event_handler.lua:45>

I am not able to trivially reproduce this one. Do you have some reproduction steps or details I can use? Perhaps a save game with specific conditions?

Happens when putting down a blueprint from any blueprint book for me, either in the library or in the inventory (error message is slightly different, line 2020 or 2022 depending)

That was it. I read book as library, not an actual book. Reproduced.

I've added a PR to the github that fixes the issue if you want to take a look.
It's pretty awkward as you have to also handle blueprint books that contain blueprint books, such as this.
https://github.com/raynquist/balancer/blob/master/blueprints/balancer_book.txt

Thanks TwistableGolf! Was on a lot of that path in my fix as well. There are some issues there, primarily when dealing with BP books in the library. That get_active_index returns the slot the BP is in the book, not the index in the contents array. I'm putting together a bug / mod interface request to either fix this call or provide a way to get the BP from the slot info. As it stands there is no way to determine which BP a player is putting down if they picked up a book from the library.

Short term workaround is to select the specific BP from inside the book and not the book itself.

I get that is impacts ALL BPs when this mod is loaded. I will be posting an update to try and avoid that part, but it may mean that BPs dealing with the combinator may not work quite right.

Forgive me if it's not relevant, but raiguard posted here recently: https://forums.factorio.com/viewtopic.php?t=88100&start=20

Forgive me if it's not relevant, but raiguard posted here recently: https://forums.factorio.com/viewtopic.php?t=88100&start=20

Related, but there is a bug that makes what he describes here non-functional, which is the curx of the issue. Once this bug is resolved I'll be able to put in a proper fix to the mod.

https://forums.factorio.com/viewtopic.php?t=126868

This is most likely this bug: https://github.com/kryojenik/LTN_Combinator_Modernized/issues/61

and this is the fix: https://github.com/kryojenik/LTN_Combinator_Modernized/pull/62

I run locally with this patch and I blueprint the combinator all the time without problems

[do you prefer bug reports here or on github?]

This is most likely this bug: https://github.com/kryojenik/LTN_Combinator_Modernized/issues/61

and this is the fix: https://github.com/kryojenik/LTN_Combinator_Modernized/pull/62

I run locally with this patch and I blueprint the combinator all the time without problems

[do you prefer bug reports here or on github?]

[do you prefer bug reports here or on github?]

Both are fine. I appreciate the PR! I'm away from my personal systems this week, so I should get to this on Friday.

This is fixed if you are running Factorio 2.0.35 (experimental). Before 2.0.35 placing BPs over existing LTN Combinators may not have the expected signals set. Once a version greater to or equal 2.0.35 goes stable, the dependency will be updated.