Stack Overflow?

[awilliamson]

Using the extends method, and upon calling self:super("init",params) from within my extended class' init function It appears to recursively call.

[ERROR] gamemodes/inpsb/gamemode/classes/../classes/hudpanel.lua:7: stack overflow
  1. super - gamemodes/inpsb/gamemode/classes/../classes/hudpanel.lua:7
   2. super - gamemodes/inpsb/gamemode/classes/../classes/hudpanel.lua:7
    3. super - gamemodes/inpsb/gamemode/classes/../classes/hudpanel.lua:7
     4. super - gamemodes/inpsb/gamemode/classes/../classes/hudpanel.lua:7
      5. super - gamemodes/inpsb/gamemode/classes/../classes/hudpanel.lua:7
       6. super - gamemodes/inpsb/gamemode/classes/../classes/hudpanel.lua:7
        7. super - gamemodes/inpsb/gamemode/classes/../classes/hudpanel.lua:7
         8. super - gamemodes/inpsb/gamemode/classes/../classes/hudpanel.lua:7
          9. super - gamemodes/inpsb/gamemode/classes/../classes/hudpanel.lua:7

HudPanel.lua:

local HudComponent = GM.class.getClass("HudComponent")
local C = HudComponent:extends()

function C:init(x, y, width, height, backgroundColor, autosize)
    self:super("init",x, y, width, height)
        ... etc

HudComponent.lua:

local C = GM.LCS.class()

function C:init(x, y, width, height)
    self.x = x
    self.y = y
        ... etc

I can't see anything wrong with that as a class extension, any help is much appreciated.

NB - Not sure if I've given you enough to diagnose the issue here, but I would have to put the whole system on otherwise, due to the way I integrated the class system into my creation system.

[Yonaba]

Hmm, strange. I can't see what's going on from the sample, you might want to show a bit more. It seems you made LCS module global, and GM.LCS being a reference to this. Class C (in HudComponent.lua) seems to be the root class here, created via GM.LCS.class(). Which is fine.Then, in HudPanel.lua, how come the new class C is get from GM.class.getClass(''HudComponent") ? I am not sure about what's behind that reference, as I was expecting it to be a direct reference to C (in HudComponent.lua) class ?

[awilliamson]

I'm rolling a custom class creation system. GM.class is that system and getClass just retrieves classes which I've saved to it. I use that for getting classes into individual class files, for use in extending. The self:super call was doing a recursive issue with only HudPanel ( which is the most commonly derived class ), for the other classes which are derived very little if at all, the original self:super method worked.

For the HudPanel I had to use self:getClass():init(args) for it to work non-recursively. Is there any limitation onto the number of classes which can extend one class. I have a lot of other classes which extend HudPanel.

[Yonaba]

Hi, sorry for the delay.
Ach...I see what's going on here. Well, it seems there's a recursion issue when the inheritance tree reaches two (or more) levels of depth. This is due to the internals of the library. I'll fix that, when I have the chance.

Anyway, as a very simple workaround, instead of calling super, which can result in a stack overflow problem, you can explicitely call the superclass constructor. See the examples below:

local LCS = require 'lcs'

local A = LCS.class()
function A:init(a)
    self.a = a
end

local AA = A:extends()
function AA:init(a,b)
    A.init(self,a)
    self.b = b
end

local AAA = AA:extends()
function AAA:init(a,b,c)
    AA.init(self, a, b)
    self.c = c
end

local a = AAA(1,2,3)
for k,v in pairs(a) do
        print(k,v)
end

Output:

>lua -e "io.stdout:setvbuf 'no'" "t.lua" 
a   1
c   3
b   2
>Exit code: 0

You can altenaltively dive into 30log, which solves this problem.

[awilliamson]

Yeah had a feeling it was a limit with extension of classes. Currently got your lib running for my class system, got to say It's working well.

The new way which I'm making the classes I need I shouldn't require more than 3 levels, but if you're working on a fix, that's great.

Invoking the class method directly is a little bit bad, I'd prefer not to do it if possible, although I usually only use it during Init and Render and It only ever calls the super method, never another class, so it's not too bad.

Thanks for looking into it.

[csun]

Was just having this exact same problem. Perfect timing for the creation of this issue. Hope you get it fixed, and thanks for the useful library.

[awilliamson]

Hopefully this gets fixed at some point. I don't know at the current time If I'm going to require the use of 3 or so extensions, as the full system I'm working with isn't designed yet.

Can we get a time frame on a fix?