Factorio Forums

Posted: **Thu Jun 06, 2019 1:45 pm**

What?

pcall(some_function) will protect event handlers of other mods than the pcall'ing mod if some_function triggers an event.

Reproduction

Just start a new game and see the error being printed.

: pcall.png (267.72 KiB) Viewed 686 times

Test-mod-AB.7z: (683 Bytes) Downloaded 32 times

Test Mod A:

Code: Select all

script.on_event(defines.events.on_player_created,function(e)
  local A,B = pcall(function() game.players[e.player_index].force = 'neutral' end)
  game.print('A:'..tostring(A))
  game.print('B:'..tostring(B))
  end)

Test Mod B:

Code: Select all

script.on_event(defines.events.on_player_changed_force,function(e)
  error('This should not be protected?.')
  end)

Expected Behavior

I'm not even sure this is really a bug. It just *feels* wrong. I kinda expected pcall to only protect code inside my own mod.

Posted: **Thu Jun 06, 2019 2:58 pm**

Thanks for the report however that's what pcall does: it traps all errors that result from code executed inside of the pcall.

Unless you're parsing input from the player you never want to use pcall as it will just hide bugs in your code. If that 1 scenario didn't exist I would disallow the use of pcall in mods.

Posted: **Thu Jun 06, 2019 3:25 pm**

Rseding91 wrote: Thu Jun 06, 2019 2:58 pm Unless you're parsing input from the player

That is exactly what i was doing. It's my "/sudo" mod. I was just suprised that it catches event handlers in *other* mods. Thanks for confirming it's not a bug.

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[0.17.42] pcall protects other mods event handlers

[0.17.42] pcall protects other mods event handlers

Re: [0.17.42] pcall protects other mods event handlers

Re: [0.17.42] pcall protects other mods event handlers