Re: debug.getlocal from within return hook

[Philipp Janda <siffiejoe@...>]

Hi!

Am 19.05.2015 um 10:33 schröbte Philipp Janda:
> Thanks very much! I can confirm that a single explicit return value
> fixes the behavior of the test script on Lua 5.1, 5.2, and 5.3 (an empty
> `return` is insufficient). Unfortunately, in my original code where I
> encountered the problem I already had an explicit return value (and it
> still doesn't work except on LuaJIT). I'll try to come up with an
> updated test case.

As promised here the updated test case. Interestingly, which local 
variables get garbled depends on which local variable I return 
(unfortunately the original code is primarily used on module chunks 
where I often return the first local I define (`local M = {}`)) ...

Output (variable `b` is returned from `func`):

    func	a	10
    func	b	table: 0x11b3da0
    func	c	function: 0x11b4200
    func	d	true
    func	e	string

    HOOK	a	10
    HOOK	b	table: 0x11b3da0
    HOOK	c	table: 0x11af7b0
    HOOK	d	function: 0x11af590
    HOOK	e	5


Philipp


local function func()
  local a = 10
  local b = {}
  local c = function() end
  local d = true
  local e = "string"
  local ii, name, value = 2, debug.getlocal( 1, 1 )
  while name do
    if #name == 1 then
      print( "func", name, value )
    end
    ii, name, value = ii+1, debug.getlocal( 1, ii )
  end
  print()
  return b
end

local function hook()
  if debug.getinfo( 2, "f" ).func == func then
    local i, name, value = 2, debug.getlocal( 2, 1 )
    while name do
      if #name == 1 then
        print( "HOOK", name, value )
      end
      i, name, value = i+1, debug.getlocal( 2, i )
    end
  end
end

debug.sethook( hook, "r" )
func()
debug.sethook()