lua crashes while using luajson

[aisbaa]

To reproduce:

1. bootstrap new lua
2. run code below with lua interpreter

local json = require "json"
local jss = json.decode("")

I get segmentation fault.

$ luadist list

Installed modules:
==================

  lpeg-0.11 (-x86_64)
  lua-5.1.5 (-x86_64)
  lua-git-0.5   (-x86_64)
  luadist-activate-0.3  (-x86_64)
  luadist-git-0.2.5 (-x86_64)
  luafilesystem-1.6.2   (-x86_64)
  luajson-1.2.1 (-x86_64)
  luasocket-2.0.2   (-x86_64)
  penlight-1.1  (-x86_64)
  srlua-5.2 (-x86_64)
  zlib-1.2.6    (-x86_64)

[drahosp]

Thank you for reporting, I will look into it. I see the bootstrap process fails to detect your system name, can you also post uname -a please.

[drahosp]

I failed to reproduce the issue on OSX and Ubuntu Linux. Waiting for details about your os/system.

[aisbaa]

Sure, I use Archlinux, I'll try on ubuntu today.

Linux  3.8.4-1-ARCH #1 SMP PREEMPT Wed Mar 20 22:10:25 CET 2013 x86_64 GNU/Linux

[aisbaa]

Tried Ubuntu 12.04 and Ubuntu 12.10 (both 64-bit) and was unable to reproduce the crash,
but succeeded on Debian-stable (64-bit) and ArchLinux (64-bit). Also I've noticed that lpeg.so has
some internal functions visible which is generally not a good idea. There is an assumption, that
depending on OS environment loader might put wrong address to the function name breaking codeflow
logic.

One more question would be is there any documented way to strip all non-exported symbols
from libraries in LuaDist? CMake should be used in some way to declare libary linking policy.

gdb backtrace and lpeg symbols

[drahosp]

Thank you.
LuaDist compiles the code as is and will strip the final executable unless you build it with debug enabled. Generally default CMake settings make sense in this context for all target platforms and compilers.

I will try to replicate the issue on my end using Debian and investigate possible solutions.

Please can you also try using lpeg-0.10.2 and see if the error persists.

> luadist remove lpeg
> luadist install lpeg-0.10.2

[mnicky]

I have a 32-bit Debian 6.0 so I tried, just out of my curiosity, whether I can reproduce this:

$ bin/luadist install luajson -debug
$ bin/lua
> json = require "json"
> jss = json.decode('')
.../tmp/LuaDist/bin/../lib/lua/json/decode.lua:91: Invalid JSON data
stack traceback:
    [C]: in function 'assert'
    .../tmp/LuaDist/bin/../lib/lua/json/decode.lua:91: in function <.../tmp/LuaDist/bin/../lib/lua/json/decode.lua:89>
    (tail call): ?
    (tail call): ?
    stdin:1: in main chunk
    [C]: ?
> jss = json.decode('{"key": "val"}')
> return jss
table: 0x905c2e8
> for k,v in pairs(jss) do print(k,v) end
key val

...and it seems to be working.

[aisbaa]

Using lpeg-0.10.2 worked for me.

[dhkolf]

This is a problem with LPeg 0.11 and is fixed for LPeg 0.12. Here is a discussion about it: http://lua-users.org/lists/lua-l/2013-04/msg00327.html

[drahosp]

Marking this as wont-fix. The solution is to update to lpeg 0.12 which is now available in the repository. Thank you!