Locale dependent error in addRangeCheck() function

[michael0710]

The generate validator function generates lua code as string object which is then used to validate JSON data.
If the given JSON schema contains a numeric value with range limitation, the function addRangeCheck(...) is called.
As this function uses string.format to generate if statements, the range limit which is given as type number will convert the number to a string. Depending on he active locale, the number is represented with either a comma or a full stop as a decimal separator. If a comma is used as decimal separator, the generated lua code is invalid.

See:

jsonschema/lib/jsonschema.lua

Line 577 in a55072d

local function addRangeCheck(ctx, op, reference, msg)

A possible fix would be to set a different locale temporarily to make sure a full stop is used as decimal separator, e.g.:

local function addRangeCheck(ctx, op, reference, msg)
  active_locale = os.setlocale(nil)
  os.setlocale("C")
  ctx:stmt(sformat('  if %s %s %s then', ctx:param(1), op, reference))
  ctx:stmt(sformat('    return false, %s("expected %%s to be %s %s", %s)',
                    ctx:libfunc('string.format'), msg, reference, ctx:param(1)))
  ctx:stmt(        '  end')
  os.setlocale(active_locale)
end