"attempt to get length of a number value (local 'sfail')" when parsing wrong syntax

[PhilipRoman]

Error

lua5.3: /usr/local/share/lua/5.3/lua-parser/parser.lua:478: attempt to get length of a number value (local 'sfail')
stack traceback:
    /usr/local/share/lua/5.3/lua-parser/parser.lua:478: in function 'lua-parser.parser.parse'
    <my code>
    [C]: in ?

Steps to reproduce

require 'luarocks.loader'
local parser = require 'lua-parser.parser'

local source = "while true do"
local ast, err = parser.parse(source, "sourcefile.lua")

Seems like this happens with any invalid syntax.

Versions

luarocks 3.0.4
lua-parser 1.0.0-1
LPegLabel 1.5.0-1
Lua 5.3.3

Additional info

This issue does not occur with lua-parser 0.1.1-1. The parse function returns normally and error message is sourcefile.lua:1:13: syntax error, unexpected 'EOF', expecting 'end', 'return', '(', 'Name', 'goto', 'break', '::', 'local', 'function', 'repeat', 'for', 'do', 'while', 'if', ';'

[andremm]

Thanks for the report @PhilipRoman! This issue was introduced by LPegLabel 1.5.0 and it indeed will happen to any invalid syntax, because now LPegLabel is returning the subject position (number) related to the error instead of the subject itself (string) where the failure occurred. I still have to see how to fix this because this change is breaking several tests due to different error positions being reported by LPegLabel. For now, I recommend using either lua-parser 1.0.0 with LPegLab 1.4.0 or lua-parser 0.1.1, which is basically the same parser, but using LPeg instead of LpegLabel.

[andremm]

The solution was really simple. I just needed to use the error position being returned, as it wasn't necessary to calculate it anymore. I generated a new version to make sure the right LPegLabel version is used with the fix, that is, from now on lua-parser 1.0.1 requires at least LPegLabel 1.6.0.