[JASS] Return Bug

[toofless]

Hey, I've had a break from editing and it was conveniently over the period that 1.24 was released.

Release notes talk about false positives (the return bug) and I'm not too sure about this.

I heard somewhere that basicly you can't use 2 returns in one function. Can someone clarify what I need to change in my map to get it working again?

I didn't even know I'd used any return bug and I haven't used any handle functions so I'm at a loss at what I need to fix.

Please?
Thanks :>

 

[Adiktuz]

Hey, I've had a break from editing and it was conveniently over the period that 1.24 was released.

Release notes talk about false positives (the return bug) and I'm not too sure about this.

I heard somewhere that basicly you can't use 2 returns in one function. Can someone clarify what I need to change in my map to get it working again?

I didn't even know I'd used any return bug and I haven't used any handle functions so I'm at a loss at what I need to fix.

Please?
Thanks :>

dont know anything bout this but I read in the 1.24b patch note that this bug is already fixed..

 

[thelifelessone]

(according to what I know...)
The return bug:

function H2I takes handle h returns integer
     return h
     return 0
endfunction

would allow a JASSer to return a unique integer ID from a handle.
It also allowed you to execute Bytecode from the map (don't ask me how. I have no idea...), which allowed a lot of pretty awesome things, but also made bad things (virus maps).

The newest patch has made it so the return bug isn't possible, but we can still get the handle ID with something like:

function H2I takes handle h returns integer
     return GetHandleId(h) // GetHandleId() is a new native, which will take a handle, and return it's integer ID.
endfunction

 

[Vulcano]

I heard somewhere that basicly you can't use 2 returns in one function. Can someone clarify what I need to change in my map to get it working again?

you can use 1+ returns in a function

You said you don't use handle functions, so probably you just have to (re)save your map in the main WE screen (not in object or trigger editor).

 

[Yixx]

The return bug is typecasting in a function to get either an ID of a handle (very commonly used), the handle of an ID, or just bullshit like Location2Real (I have seriously seen that once, for some save/load thing).
Typecasting means you return an other type of variable (integer, real, handle,widget) than is behind the "returns".
Though this shouldnt be possible, it was because only the last 'return' was type-safe.
Because of this, in any return before that one you could return whatever you wanted.
Like this:

 function H2I takes handle h returns integer
    return h
    return 0
endfunction

h is no integer, but still this compiles, for only the last return is type-safe and 0 is an integer. That is how typecasting, A.K.A. the return bug works. Blizzard did some things to solve this, but i am not sure wether it is already fully fixed or if there are still workarounds. Either way, a virus could be generated by returning code (returns code, and do some shit with it, due to this, returning code isnt possible at all anymore. The map will not run if code is returned, or if there is a return bug used.

 

[toofless]

Oh that's hax0r lol

So my problem is definately not to do with typecasting.

I haven't updated JNGP or anything since new patch. Is there an update? Maybe this is what is causing me to get "map not found" when I try to open it in warcraft.

 

[thelifelessone]

There isn't an update to JNGP, but there is an update to JassHelper, and the Optimizer.

 

[HINDYhat]

Release notes talk about false positives (the return bug) and I'm not too sure about this.

All of the return bug fix bugs (lol) have been fixed in 1.24b, so if your code does not include the return bug, it should compile properly.

 

[toofless]

Hmm yes it worked. I updated JassHelper, re-compiled and all is well. Thanks for you help.