Percentage Encode showing weird behaivor

[x48zhu]

Hello, I'm looking at this percentage encoding, where it does this:

  str = str:gsub("\n", "\r\n")
  str = str:gsub("([^%w ,;=_%%%-%.~])", char_to_hex)
  str = str:gsub(" ", "+")

I noticed a weird encoding issue: it encodes journey into jourrney (double r). My suspicion is the first line causes this, even though it doesn't make sense.

This seems to happen only on certain platforms or Lua versions (I'm not sure what triggers that). For example, it didn't happen on my local while running the unit test, but I noticed this issue while on a machine.

This problem stops to happen after I change the code to this:

  str = string.gsub(str, "\r?\n", "\r\n")
  str = string.gsub (str, "([^%w%-%.%_%~%% ,;=])", char_to_hex)
  str = string.gsub (str, " ", "+")

[yangxikun]

What's the origin str?
What platform and Lua version causes this issue?