lua/testes/cstack.lua

-- $Id: testes/cstack.lua $
-- See Copyright Notice in file all.lua


print"testing C-stack overflow detection"

-- Segmentation faults in these tests probably result from a C-stack
-- overflow. To avoid these errors, you should set a smaller limit for
-- the use of C stack by Lua, by changing the constant 'LUAI_MAXCCALLS'.
-- Alternatively, you can ensure a larger stack for the program.


local function checkerror (msg, f, ...)
  local s, err = pcall(f, ...)
  assert(not s and string.find(err, msg))
end

do  print("testing stack overflow in message handling")
  local count = 0
  local function loop (x, y, z)
    count = count + 1
    return 1 + loop(x, y, z)
  end
  local res, msg = xpcall(loop, loop)
  assert(msg == "error in error handling")
  print("final count: ", count)
end


-- bug since 2.5 (C-stack overflow in recursion inside pattern matching)
do  print("testing recursion inside pattern matching")
  local function f (size)
    local s = string.rep("a", size)
    local p = string.rep(".?", size)
    return string.match(s, p)
  end
  local m = f(80)
  assert(#m == 80)
  checkerror("too complex", f, 2000)
end


do  print("testing stack-overflow in recursive 'gsub'")
  local count = 0
  local function foo ()
    count = count + 1
    string.gsub("a", ".", foo)
  end
  checkerror("stack overflow", foo)
  print("final count: ", count)

  print("testing stack-overflow in recursive 'gsub' with metatables")
  local count = 0
  local t = setmetatable({}, {__index = foo})
  foo = function ()
    count = count + 1
    string.gsub("a", ".", t)
  end
  checkerror("stack overflow", foo)
  print("final count: ", count)
end


do   -- bug in 5.4.0
  print("testing limits in coroutines inside deep calls")
  local count = 0
  local lim = 1000
  local function stack (n)
    if n > 0 then return stack(n - 1) + 1
    else coroutine.wrap(function ()
           count = count + 1
           stack(lim)
         end)()
    end
  end

  local st, msg = xpcall(stack, function () return "ok" end, lim)
  assert(not st and msg == "ok")
  print("final count: ", count)
end


do
  print("nesting of resuming yielded coroutines")
  local count = 0

  local function body ()
    coroutine.yield()
    local f = coroutine.wrap(body)
    f();  -- start new coroutine (will stop in previous yield)
    count = count + 1
    f()   -- call it recursively
  end

  local f = coroutine.wrap(body)
  f()
  assert(not pcall(f))
  print("final count: ", count)
end

print'OK'