SDIFF is broken

check_sdiff_pipeline.lua

pcall(require, 'luarocks.require')

local sidereal = require 'sidereal' -- sudo luarocks install sidereal --from=http://luarocks.org/repositories/rocks-cvs

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-- Some value printing code
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require 'lua-nucleo.module' -- sudo luarocks install lua-nucleo
require 'lua-nucleo.strict'

local tstr = import 'lua-nucleo/tstr.lua' { 'tstr' } -- Lua value to string

local N = 1
local P = function(...) print(N .. ":", tstr(assert(...))); N = N + 1 end

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-- Connect to Redis
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local R = assert(sidereal.connect("localhost", 6379))

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-- Fill data
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R:sadd("MYSET1", "one")
R:sadd("MYSET1", "two")
R:sadd("MYSET2", "two")
R:sadd("MYSET1", "three")

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-- This works
--------------------------------------------------------------------------------

P (R:sdiff("MYSET1", "MYSET2"))
--> 1: {three=true,one=true}

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-- This does not
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R:pipeline()
P (R:sdiff("MYSET1", "MYSET2"))
--> 2: {}
R:send_pipeline()

P (R:get_response())
--> 3: true

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-- This does not either
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P (R:multi())
--> 4: "OK"
P (R:sdiff("MYSET1", "MYSET2"))
-->
--[[
lua: /usr/local/share/lua/5.1//sidereal.lua:488: bad argument #1 to 'ipairs' (table expected, got string)
stack traceback:
	[C]: in function 'ipairs'
	/usr/local/share/lua/5.1//sidereal.lua:488: in function </usr/local/share/lua/5.1//sidereal.lua:486>
	(tail call): ?
	check_sdiff_pipeline.lua:57: in main chunk
	[C]: ?
--]]

P (R:exec())
--> (not reached)