idioty wrote:

I tried with 1.2.0, 1.3.3 and 1.4.0-beta1 version of OpenTTD in Mac OSx 10.9.

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krinn wrote:

I think the doc is fine.
But the DoCommand need a valid railtype pass.

This is how it is fix in RemoveRail :
if (!IsRailTypeAvailable(GetCurrentRailType())) SetCurrentRailType(GetRailType(tile));

So this part is missing in RemoveRailTrack and if someone didn't set a railtype the docommand will fail.

But you should note the doc help for SetCurrentRailType : http://nogo.openttd.org/api/trunk/classGSRail.html# 32966cfb53f523d9bbed7f6b3f281854
"Set the RailType for all further GSRail functions. "
This kinda imply a default precondition for any rail functions, so you should always set a railtype before using any other rail functions, including after loading a game (i suppose this is how you find the bug).

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idioty wrote:

Ok, thx!
But I saw in other documentation of function, example: GSRail::BuildRailDepot.
I think this is necessary in documentation.
I can't use any rail function before this, so I could not!
I searched for about an hour, that does not work....
no matter... :)

This comment was imported from FlySpray: https://bugs.openttd.org/task/5853#comment12910

krinn wrote:

It's documented in build functions, as prior to build something you must know what kind of railtype to use.
While this function is to remove something that exists, so it imply you have create it first (so set a railtype before to create the rail)...

That's why i suppose you got that bug because you are loading a savegame, where you could have rails built already, while still never have set any railtype. I'm not sure if any newGRF can invalidate a railtype itself by date or other usage, and i don't think right now any AI can brought another company.
You might fall into this if you AI have its randomai setting enable, and the ai is use intead of another one and seeing rails built by other ais. But again, that will happen when loading too.
Notice the dead end : if a newGRF add a railtype, you create rails with it, but when loading the savegame without the newGRF, no railtype is avaiable now because of the missing newGRF : so this function will always fail, even rails exists on the map. This is that kind of awkard situation that made devs change openttd to not allow missing newGRF savegame to be loaded without a trick.

So in order to build, you must know the railtype to use, but in order to remove, you need any railtype set to let the docommand works (well, this is how i understand its need, i might be wrong, but i don't think you need the same railtype as the rail to remove, as you pass the railbit to remove, no need to know really the railtype of the rail), and this is why RemoveRailTrack just try to pass the current railtype to the docommand, as you need one, but any.
I don't think the doc need a change, just adding the missing <if (!IsRailTypeAvailable(GetCurrentRailType())) SetCurrentRailType(GetRailType(tile));> will do the job fine.

You should make a better handling at using SetCurrentRailType, maybe the SetCurrentRailType doc could be change to emphasis even more it's really a precondition to any rails functions, anyway, you'll get into trouble at not taking enough care about this one when new railtype appears in game, you'll see how easy you'll be end with mixed railtype in your constructions.

This comment was imported from FlySpray: https://bugs.openttd.org/task/5853#comment12912

idioty wrote:

Yeah, I did not find the GSRail description that is a prerequisite.
I've never made ​​AI, never even brought up rails, so I did not know about it.
I just want to remove rails due to suction. :)

... sorry my bad english, I don't speak english! :)

This comment was imported from FlySpray: https://bugs.openttd.org/task/5853#comment12915

frosch closed the ticket.

Reason for closing: Fixed

in r26279. Setting railtype is no longer required for removing rail. It will remove any railtype anyway.

This comment was imported from FlySpray: https://bugs.openttd.org/task/5853