A lot of the events are missing an explanation for when the `player_index` will be empty. As for some it relates to how a script raised the event and what options it passed in (which may not always be apparent).
i.e. https://lua-api.factorio.com/latest/events.html#on_marked_for_deconstruction
on the ...

When you try to run a replay of a save made in an older version the below message is shown. The message lists the current version twice and not the version the replay was made in.
In this example as seen by the saves map version and Mods > base version.

Edit: Moved to right thread

The function LuaPlayer.remove_alert takes a table of fields, including one named "prototype". In the API docs its listed as type "LuaEntityPrototype?", however, if you provide an entity prototype object (LuaEntity.prototype) you get back the error message: 'prototype': string expected, got table

If ...

In the API Docs the function LuaInventory.set_filter has the param filter of type string . However I believe it should be string? based on its description for setting a nil value to clear the filter.

Page: https://lua-api.factorio.com/latest/LuaInventory.html#LuaInventory.set_filter

Param ...

When a prototype has a selection_box (possibly also collision_box ?) set to be non centered, this is placed based on the entities 4 main directions (N, E, S, W) cleanly, but for the extra rotations (NE, SE, SW, NW) in an 8 way rotatable entity the offsets are always as if the rotation is north ...

Yea I hit this as well.
Had to do a whole process to; catch build, review validity, if bad refund and show to player valid placement positions.
Was a bunch of code and added complexity to work around this issue.

At present there is no way to find a placement location for either a non north direction or a non 0 orientated entity.
Also you can't check buildability of a non 0 orientated entity.

My example is trying to teleport a player's car at its current orientation. However, I can see finding a placement ...

The below code snippet is invalid as it doesn't have the `count` field in the table argument.

/c
local player = game.player
if player.crafting_queue_size > 0 then
player.cancel_crafting {index =1}
end

However it gives the error message:
Error: 'index': real number expected got nil.

Tested ...

In 1.1.55 and before you could obtain the the autoplace_specification from a tree LuaEntityPrototype, but in 1.1.56 this isn't obtainable and it isn't listed as an intentional loss in the 1.1.56 changelog. its also still in current documentation.
https://lua-api.factorio.com/latest ...

You can't change an artillery wagons force via Lua API script. It accepts the request, but the force doesn't change.

1: Load save: arty wagon force test.zip
2: script to change the force of the player selected entity:
/c
local carriage = game.player.selected
game.print("pre: " .. carriage.force ...

The time_to_live for a character-corpse is listed as uint32. However if you put a max uint32 value the corpse vanishes instantly.
https://wiki.factorio.com/Prototype/CharacterCorpse#time_to_live
Assume the same issue exists for regular corpse.

In my testing I found that the vanishing is somewhere ...

On the main page (https://lua-api.factorio.com/latest/index.html) the Classes header isn't clickable, but the Events header further down the page is. There is the Classes page that I assume the header should link to: https://lua-api.factorio.com/latest/Classes.html

If you interact with a train carriage that is mid removal and get it to re-connect to another carriage you can crash the game. The on_train_created event gives you access to this mid removal stage.

Logic:
remove a locomotive from a 2 entity train. The game has to disconnect the loco first before ...

thanks Boskid
raised to the Comfy scenario devs in case there is anything odd on their side this flags

reproduction steps from a clean copy of the scenario following the usage path the server hosting player did in my previous error case.
Please note I am not the owner of the scenario, Comfy is.

This looks to be related to downloading a scenario from an MP game is somehow getting in to the weird map ...

Ignore this post - see 3rd post with new simpler reproduction steps.

edit: this occurs with just starting the scenario, no mods required it seems.
scenarios.zip


New Game > User scenarios > Chronosphere

Didn't want to edit original post as I see Boskid has claimed it in title.


factorio ...

Ignore this post - see 3rd post with new simpler reproduction steps.

When I load the below save based on a scenario and mods everything is fine, however, when I click to Restart the map Factorio hard crashes.
30.413 Error RollingStock.cpp:996: Internal error in RollingStock ...

Issue: a player can fast replace an entity over itself with a different rotation, but a ghost placed over an entity with fast replace and a different rotation is set back to the original rotation.
https://gfycat.com/diligentblackandwhitehoiho

1: place steam engine facing north.
2: hold steam ...

The process that a mod makes a request via the API (either function or to get/set a field) would be helpful. I got the below answer via Discord from Bilka that all LuaObject instances returned to my mod from the API have 0 field data. So for UPS optimised mods we should really be caching every field ...